. 8
( 9)


nothing greater can be conceived to exist, that it cannot even be conceived
not to exist; and this being thou art, O Lord, our God.3
In his Fifth Meditation, Descartes offers a similar proof for the exis-
tence of God as a supremely perfect being:
it is quite evident that existence can no more be separated from the essence of
God than the fact that its three angles equal two right angles can be separated
from the essence of a triangle, or than the idea of a mountain can be separated
from the idea of a valley. Hence it is just as much of a contradiction to think
of God (that is, a supremely perfect being) lacking existence (that is, lacking
a perfection), as it is to think of a mountain without a valley.4
Both versions argue by reductio ad absurdum that there is a contra-
diction in conceiving the nonexistence of the ens realissimum; the
argument can be schematized as follows:5
1. It is possible to conceive of an ens realissimum (that than which
nothing greater can be conceived or the supremely perfect being).
2. Assume that this being can be conceived not to exist (that the idea
of existence can be separated from its essence).
3. A being that cannot be conceived not to exist is greater than one
that can be conceived not to exist. (Existence is a perfection.)
4. By 3, if the ens realissimum can be conceived not to exist, then
one can conceive of something greater than it. (If existence can be
separated from its essence, then it is possible to conceive a being
more perfect than it.)
3 4 Descartes, Philosophical Writings, 2:46.
Anselm™s Basic Writings, 6“9.
5 As Van Cleve points out, Kant is probably responding directly to Descartes™s version; cf.
A602/B603. Van Cleve also discusses both modal and non-modal versions of the argument,
in Problems from Kant, chapter 12.
Transcendental illusion III 269
5. The concept of something greater than the ens realissimum is self-
6. Therefore, the assumption in 2 is false: the ens realissimum cannot
be conceived not to exist. (Existence cannot be separated from its
7. Therefore, the ens realissimum exists necessarily.

Because both arguments claim that existence is contained in the mere
concept of the ens realissimum, the necessity attributed to God™s being
is absolute or logical necessity.
Kant raises two main objections to the proof: ¬rst, that the idea of
an absolutely or logically necessary being is not a determinate concept
of an object; and second, that the proof errs by treating existence as
a real property or determination of objects. Most of the discussion
focuses on the second point, which Kant defends in a variety of ways.
This criticism has traditionally been taken more seriously, both for
its independence of transcendental idealism, and for anticipating the
analysis of existence in modern logic.
Kant ¬rst attacks the notion of an absolutely necessary being.
Beyond the nominal de¬nition as “something whose non-being is
impossible” (A592/B620), we have no determinate concept of such
a thing. The idea of unconditional or absolute necessity is an idea
of reason and not a concept of the understanding. Moreover, logical
necessity properly applies only to analytic judgments, which presup-
pose the conditional or possible existence of things. For example, from
the logical necessity of the judgment “a triangle has three angles,” one
cannot infer the existence of triangles, but only that if triangles exist,
then they must have three angles. The power of transcendental illu-
sion leads us to think that one is entitled to infer that something exists
necessarily whose concept is arbitrarily de¬ned to include existence
(A594/B622). From this criticism it follows that attempts to prove
that such a being is an ens realissimum are doubly suspect, since the
latter idea is also devoid of objective meaning.
The more fundamental error is treating existence as a real property
of things. Kant argues that although in existential judgments (i.e., “x
exists”), existence functions as a grammatical or “logical” predicate, it
nevertheless is not a real predicate representing a property of objects.
He develops this point in three interrelated arguments: ¬rst, that all
Transcendental illusion III
existential judgments are synthetic, so existence claims can never be
analytic; second, that concepts of objects can contain only possible
existence and never actual existence; and third, that existence claims
“posit” an object rather than determining its concept. As we shall see,
commentators disagree on the success of Kant™s attack.
First Kant claims that although judgments that predicate real prop-
erties of objects are analytic when the property is essential, existential
judgments are always synthetic: “is the proposition, This or that
thing . . . exists . . . an analytic or a synthetic proposition? If it is the
former, then with existence you add nothing to your thought of the
thing” (A597/B625). His point is that whereas analytic judgments are
only ampliative, existential judgments must be synthetic because they
are informative. If one concedes this point, then negative existential
judgments (e.g., “God does not exist”) can never be self-contradictory,
ruling out an a priori proof for the existence of any being.
At A598/B626 Kant says that rather than representing a real pred-
icate, “a concept of something that could add to the concept of a
thing,” the concept of existence “posits” the object represented by
the concept. The (coherent) concept of a thing implies possible but
not actual existence. In general, Kant says, “if I cancel the predicate
in an identical [i.e., analytic] judgment and keep the subject, then a
contradiction arises . . . But if I cancel the subject together with the
predicate, then no contradiction arises” (A594/B622). Thus a con-
tradiction arises if one “posits” God (asserts his existence) but denies
omnipotence, but there is no contradiction in failing to “posit” God.
The judgments “God is omnipotent” and “God exists” have the same
subject concept, but only the latter judgment “posits” the object satis-
fying the concept. Kant reinforces this point with his famous example
of the concept of a hundred dollars:

A hundred actual dollars do not contain the least bit more than a hundred
possible ones. For since the latter signi¬es the concept and the former its
object and its positing in itself, then, in case the former contained more than
the latter, my concept would not express the entire object and thus would
not be the suitable concept of it. But in my ¬nancial condition there is more
with a hundred actual dollars than with the mere concept of them (i.e., their
possibility). (A599/B627)

In other words, the concept of the hundred dollars is the same whether
I judge that I actually have a hundred dollars or merely think that I
Transcendental illusion III 271
might have a hundred dollars. But the two judgments make different
assertions: the world in which I own a hundred dollars is objectively
different from one in which I do not. Therefore, the actual existence
attributed to the hundred dollars cannot be included as a property in
its concept. If it were, then I could improve my ¬nancial condition
simply by including the concept of existence in the concept of large
sums of money.
This echoes a criticism made of both Anselm™s and Descartes™s argu-
ments. In replying to Anselm, Gaunilo argues that one could equally
claim that because one has a concept of a perfect island, such an island
necessarily exists. And in the First Objections to the Meditations, the
Dutch theologian Caterus similarly answers Descartes that although
“the complex ˜existing lion™ includes both ˜lion™ and ˜existence,™ and
it includes them essentially,” it is absurd to conclude that some lion
necessarily exists. These counter-examples illustrate Kant™s point at
A594/B622 that if existence were a real property or determination
of things, it could be arbitrarily added to any concept, with absurd
In the next paragraph Kant makes the stronger claim that existence
cannot be a property of an object. He says,
[a] Even if I think in a thing every reality except one, then the missing reality
does not get added when I say the thing exists, but it exists encumbered
with just the same defect as I have thought in it; otherwise something other
than what I thought would exist. [b] Now if I think of a being as the highest
reality (without defect), the question still remains whether it exists or not.
For although nothing at all is missing in my concept of the possible real
content of a thing in general, something is still missing in the relation to my
entire state of thinking, namely that the cognition should also be possible a
posteriori. (A600/B628; [a] and [b] designations added)

I have divided the passage into two parts, because critics make two
distinct objections to it. The standard response to part [b] is just that
it begs the question. Kant merely presupposes that (actual) existence
is not contained in the concept of the ens realissimum. While it may
be true of all other beings that their essence is distinct from existence,
the question is whether the ens realissimum is an exception to this
6 For Gaunilo see Anselm™s Basic Writings, 149“51. For Caterus see Descartes, Philosophical
Writings, 2:72.
Transcendental illusion III
The criticism of part [a] is more complex. Commentators such as
Allen Wood claim that if this argument were valid, then it would prove
that nothing could be a real predicate.7 They apparently interpret the
argument this way:
1. Suppose I conceive of something having every reality (real predi-
cate) except one under the (complex) concept C.
2. Suppose I predicate existence of this object, “C exists.”
3. If existence were a real predicate, then my assertion would change
the concept of the thing [i.e., to “the existing C”].
4. [Implied] Thus I could never succeed in asserting the existence of
an object C.
According to Wood, this argument works for any real predicate:
1 . Suppose I conceive of something under the concept C having
every reality except F.
2 . Suppose I predicate F of this C.
3 . If F were a real predicate, then my assertion would change the
concept of the thing by adding F to it, and thus the concept of
the thing would become C = {C, F}.
4 . Thus I could never predicate anything outside the concept of C
to the C.
This criticism raises the thorny issues of the nature of predication,
and the meaning of singular terms and de¬nite descriptions. Despite
lacking a theory of language, Kant™s analysis of analytic and synthetic
judgments implies a distinction between what is essentially contained
in the subject-concept, and what is predicated of it synthetically (or
contingently). It is apparent that informative contingent predications
cannot add a property to a thing™s essence. But then Wood™s point
is just that in distinguishing existence from other predicates, this
argument also begs the question.
When all these points are taken together, the question comes down
to whether Kant is right that existential judgments “posit” the object
of the concept rather than predicating a property of it. Modern logic
formalizes this view in analyzing the existential quanti¬er as a second-
order rather than ¬rst-order predicate of things. Here I follow Colin

7 See Wood, Kant™s Rational Theology, 112.
Transcendental illusion III 273
McGinn™s admirably clear summary of the contemporary view and its
weaknesses.8 While disagreeing with Kant™s claim that existence is not
a real or ¬rst-order predicate, McGinn himself rejects the ontological
argument on distinctly Kantian grounds.
The “orthodox” view of existence, championed by Russell and
Frege, consists of three theses. The ontological thesis has two sub-
theses: negatively, that existence is not a property that individuals
instantiate; and positively, that it is a property instantiated by proper-
ties of individuals. The semantic thesis maintains that “statements of
existence are really higher-order statements involving reference to a
property or . . . propositional function. The subject of the statement
is never a term for an individual but always a term for a property.”9
Thus the assertion “Tigers exist” predicates existence of the property
or predicate ˜being a tiger™ rather than of individual tigers.10 This leads
to the de¬nitional thesis that ˜exists™ can always be de¬ned in terms
of the notions of a ¬rst-order predicate or property of individuals and
˜sometimes true™ or ˜possible.™11
McGinn claims that despite its general acceptance, this orthodox
view is riddled with dif¬culties. He outlines four serious problems.
First is what it means for a property F to have instances. He argues
that de¬ning existence in terms of instantiating a property ends up
in circularity, since “it must be existent things that instantiate the
property.”12 Thus the orthodox view gives an inadequate account of
existence. The second objection is stronger, namely that the view is
not coherent. Consider statements attributing existence to properties:
they would themselves have to be interpreted as referring to a prop-
erty instantiated by the property said to exist. Thus this account of
assertions that properties exist presupposes a vicious in¬nite regress of
properties. The third problem concerns existence claims whose sub-
jects are proper names or demonstratives, such as “Venus exists,” as
well as the general claim, “Something exists.” For singular sentences,
the orthodox view pushes one toward a problematic description the-
ory of singular reference. The latter case is worse, since there is no good
candidate for a property to be instantiated. Finally, McGinn claims
that the orthodox view requires every object to have some unique
property, and entails as analytic the substantive claim that there are
8 9 Logical Properties, 20.
See McGinn, Logical Properties, chapter 2.
10 11 Logical Properties, 20. 12 Logical Properties, 22.
Logical Properties, 19.
Transcendental illusion III
no bare existents. For these reasons he prefers the analysis of existence
as a property of objects, universal to existing things. Semantically
the term operates like standard predicates ˜blue™ and ˜man,™ although
he also maintains that the existential quanti¬er can be retained for
general existence claims.13
Although McGinn rejects Kant™s logical criticism of the ontological
argument, he ends up agreeing on the idea of the ens realissimum. First
he points out that even if existence were a second-order predicate,
one could reformulate the argument to claim that the concept of
the supremely perfect being contains the property of (necessarily)
having an instance. The real problem, however, lies in the notion of
the most perfect conceivable being of any type: “We just don™t know
what it would be to be the most perfect conceivable meal or piece of
music. Similarly, the notion of, say, the most powerful conceivable
mouse makes little sense.” The problem is that the argument “trades
on notions of the maximal forms of certain attributes, particularly
perfection, that are inherently ill-de¬ned.”14 This agrees with Kant
that the concept of the ens realissimum is an idea of reason rather than
a determinate concept of the understanding.
We have seen, then, that although Kant may not conclusively refute
the ontological argument, his criticisms pinpoint two key issues that
philosophers continue to debate today: ¬rst, whether existence is a
¬rst-order property, and second, whether the concepts of a necessary
being and an ens realissimum are objectively meaningful. Both issues
touch on complex questions in logic and philosophy of language, and
thus cannot be easily resolved. Like modern logicians, and unlike tra-
ditional defenders of the ontological argument, Kant ¬rmly believes
that logic must have a uni¬ed account of existence: it will not do to
say that the concept of the ens realissimum differs from all others in
containing existence in its essence. Whatever one™s position on the
issues, one has to appreciate the signi¬cance of Kant™s contribution.

3 . t h e cosm olog i ca l a rgu m en t
Kant opens his discussion of the cosmological argument by contrast-
ing it with the ontological argument. The latter, he thinks, “contrives”
an arbitrary concept of an object “ the ens realissimum “ and then pro-
ceeds a priori by extracting existence from this concept. The strategy
13 14
Logical Properties, 50“1. Logical Properties, 50.
Transcendental illusion III 275
of the cosmological proof works in the opposite direction. First it
infers the existence of an absolutely necessary being from the exis-
tence of a contingent world. Then, in a second step, it argues that this
necessary being must be the ens realissimum. This second step, Kant
claims, implicitly assumes the validity of the ontological argument.
The classic versions of the cosmological argument were formulated
by St. Thomas Aquinas (1225“74), the Dominican theologian cred-
ited with synthesizing Aristotelianism with Christian doctrine. In the
Summa Theologiae, Aquinas details “¬ve ways” to prove the existence
of God, the ¬rst three of which are cosmological. The proofs argue
for the existence of God, ¬rst, as a “¬rst mover” at the source of
all motion (change); second, as the “¬rst cause” at the origin of all
ef¬cient causality; and ¬nally, as the necessary being underlying all
contingent existence. This third argument proceeds as follows:
We ¬nd in nature things that are possible to be and not to be, since they are
found to be generated, and to be corrupted . . . But it is impossible for these
always to exist, for that which can not-be at some time is not. Therefore, if
everything can not-be, then at one time there was nothing in existence. Now
if this were true, even now there would be nothing in existence, because that
which does not exist begins to exist only through something already existing.
Now it is impossible to go on to in¬nity in necessary things which have their
necessity caused by another, as has been already proved in regard to ef¬cient
causes. Therefore, not all beings are merely possible, but there must exist
something the existence of which is necessary . . . Therefore we cannot but
admit the existence of some being having of itself its own necessity, and not
receiving it from another, but rather causing in others their necessity. This
all men speak of as God.15
Although the ¬rst two proofs proceed somewhat differently, all three
arguments conclude that God exists as the necessary being at the
source of the contingent world.
As with most arguments, Kant™s own characterization is highly
abstract: “If something exists, then an absolutely necessary being also
has to exist. Now I myself, at least, exist; therefore, an absolutely nec-
essary being exists” (A604/B632). The argument is a posteriori because
it is based on the contingent existence of something; Kant says the
proof is called “cosmological” because “the object of all possible expe-
rience is called ˜world™” (A605/B633). But unlike the argument from

15 Aquinas, The Basic Writings of St. Thomas Aquinas, 25“7.
Transcendental illusion III
design, the particular nature of the world is irrelevant to this proof.
What makes the cosmological proof an argument for the existence
of God, according to Kant, is a second inference, that this absolutely
necessary being is the ens realissimum, or God. Although he later
details several objections to the ¬rst stage, Kant primarily attacks the
second stage. His main point, often misunderstood, is that this step,
if valid, would imply the validity of the ontological proof. Since he
previously rejected that proof, it follows that the second stage of the
cosmological proof must also be invalid.
In an obscure argument at A605/B633 Kant explains the second
stage thus:
The necessary being can be determined only in one single way, i.e., in regard
to all possible predicates, it can be determined by only one of them, so
consequently it must be thoroughly determined through its concept. Now
only one single concept of a thing is possible that thoroughly determines the
thing a priori, namely that of an ens realissimum.

Kant apparently assumes that the necessary being can be determined
only through one a priori concept, because all limited concepts of
reality are logically contingent. This reading is also suggested by Kant™s
gloss at A606“7/B634“5: “What this being might have in the way of
properties, the empirical ground of proof cannot teach; rather here
reason . . . turns its inquiry back to mere concepts: namely, to what
kinds of properties in general an absolutely necessary being would
have to have.” In any case, the only candidate for an a priori concept
determining the absolutely necessary being is the rational ideal of the
ens realissimum. Whether proponents of the cosmological argument
actually reason this way, Kant is certainly correct that the last step of
the argument must connect the absolutely necessary ¬rst cause with a
supremely perfect being. (In fact, Aquinas offers no reason for taking
the absolutely necessary being as God.) Without this inference the
argument would differ from the Fourth Antinomy argument only in
locating the necessary being outside the world.
Kant then argues that this inference implies the validity of the
ontological argument. The conclusion, “Every absolutely necessary
being is at the same time the most real being,” can be converted per
accidens to the claim, “Some most real beings are at the same time
absolutely necessary beings” (A608/B636). But since it is not possible
for more than one ens realissimum to exist, the conversion proceeds to
Transcendental illusion III 277
the universal, “Every most real being is a necessary being.” In other
words, the above reasoning entails that the concept of the most real
being contains the concept of existence, which is the crux of the
ontological argument.
Because Kant concentrates his criticism on this second stage, some
commentators mistakenly assume he considers the ¬rst stage to be
valid. But nothing could be further from the truth. In fact, the ¬rst
three of four objections detailed at A609“10/B637“8 are aimed at
the ¬rst stage. First he objects to the attempt to prove an intelligible
cause outside the world in general, since “the principle of causality
has no signi¬cance at all and no mark of its use except in the world
of sense.” Similarly, he rejects the reasoning to a “¬rst” cause to avoid
an in¬nite series of causes, both within and without experience. As
he argued in the Antinomies, an uncaused cause is neither a possible
object of experience nor a justi¬able postulation of reason. Third,
Kant reiterates the false satisfaction of reason in trying to explain the
conditioned (the contingent) by reference to an absolutely necessary
unconditioned, an idea having no determinate content. And ¬nally,
he attacks the second stage for confusing “the logical possibility of a
concept of all reality . . . with its transcendental possibility.” As we saw
earlier, the idea of all possible reality represents only the “transcen-
dental substratum” for the process of forming determinate concepts
of individuals.
Considered more traditionally, then, Kant rejects the cosmologi-
cal argument for misapplying the principle of causality beyond the
legitimate ¬eld of experience, for illegitimately assuming that an in¬-
nite series of causes is impossible, for mistakenly thinking that the
(unde¬ned) idea of an absolutely necessary being can “explain” the
existence of the contingent universe, and for hypostatizing the logical
idea of a collection of all real properties as an individual, the ens realis-
simum. Clearly Kant accepts no part of the cosmological argument.
As he puts it near the end of this section:

The ideal of the highest being is, according to these considerations, nothing
other than a regulative principle of reason, to regard all combination in the
world as if it arose from an all-suf¬cient necessary cause, so as to ground on
that cause the rule of a unity that is systematic and necessary according to
universal laws; but it is not an assertion of an existence that is necessary in
itself. (A619/B647)
Transcendental illusion III
In the next chapter we shall see how this ideal regulates the search for
empirical knowledge.

4. t he a rg um ent f rom d e si g n
The physico-theological proof, better known as the argument from
design, also makes an a posteriori argument for the existence of God.
Whereas the cosmological proof argues from the fact that something
exists contingently, this argument depends on a “determinate expe-
rience,” namely of order in nature. It concludes that God must exist
as the in¬nite intelligence responsible for such order. This argument
also enjoys a long history: Aquinas™s ¬fth proof represents one ver-
sion. In the modern period, a more familiar version appeared in the
Natural Theology (1802) of William Paley (1743“1805), Archdeacon of
Carlisle. Even before Paley™s work appeared, however, David Hume
presented a concise formulation in his Dialogues Concerning Natural
Religion, published posthumously in 1779. Of course Hume™s pur-
pose was the opposite of Paley™s; rather than accepting the proof, he
set out to refute it. Not only are his criticisms devastating, they are
among the most humorous in the history of philosophy. As we shall
see, although Kant raises many of the same objections he made to the
cosmological argument, he shares Hume™s view of other weaknesses
in the argument.
Hume™s Dialogues concern the possibility of natural theology,
that is, defending the existence of God on grounds available to
humans. They take place between three characters, representing dif-
ferent positions: Cleanthes, who advocates the argument from design,
Demea, an “orthodox” believer who defends the ontological proof,
and Philo, the skeptic. Cleanthes states the argument from design as

Look round the world, contemplate the whole and every part of it: you will
¬nd it to be nothing but one great machine, subdivided into an in¬nite
number of lesser machines, which again admit of subdivisions to a degree
beyond what human senses and faculties can trace and explain . . . The curious
adapting of means to ends, throughout all nature, resembles exactly, though
it much exceeds, the productions of human contrivance “ of human design,
thought, wisdom, and intelligence. Since therefore the effects resemble each
Transcendental illusion III 279
other, we are led to infer, by all the rules of analogy, that the causes also
resemble, and that the Author of nature is somewhat similar to the mind
of man, though possessed of much larger faculties, proportioned to the
grandeur of the work which he has executed.16
The argument compares the order exhibited in nature with that pos-
sessed by machines designed by humans. In standard form it proceeds
this way:
1. Machines created by humans are things whose parts are ordered so
as to produce a result; the whole serves a purpose, and each part is
related to achieve this purpose.
2. The universe as a whole is composed of parts that ¬t together to
achieve results.
3. Therefore, the universe resembles machines.
4. Rule of analogy: whenever two effects resemble each other, their
causes also resemble each other.
5. Therefore, the cause of the universe resembles the cause of
6. Machines are produced by (human) design and intelligence.
7. Therefore, the universe was produced by design or intelligence.
8. This cause is proportionately greater as the effect is proportionately
greater, so that the cause of the universe is much more intelligent
than the cause of machines.
9. Therefore, God exists as the intelligent cause of the universe.
Kant™s version at A625“6/B653“4 consists of four statements, com-
bining the analogy from steps 2 through 6 above into the premise:
“This purposive order is quite foreign to the things of the world, and
pertains to them only contingently, i.e., . . . through a principle of
rational order grounded on ideas” (A625/B653). Although this proof
is “the oldest, clearest and most appropriate to common human rea-
son” (A623/B651), Kant nevertheless rejects it as no more successful
than the other two arguments for the existence of God.
Like the cosmological argument, Kant divides this proof into two
parts: the ¬rst concluding that the cause of the universe is an intelli-
gent being (line 7), and the second identifying this cause with God
or the ens realissimum (line 9). Here too he objects that the second
16 Hume, Dialogues Concerning Natural Religion, part II.
Transcendental illusion III
inference assumes the validity of the ontological argument. Thus
neither a posteriori proof succeeds in avoiding the transcendental
But this is not Kant™s only criticism; like Hume, he raises several
objections to the analogy. Despite their different theories of knowl-
edge, both attack the argument for making indefensible empirical
claims, and question the comparison between human machines and
the universe. In part II of the Dialogues, Philo points out that we have
no experience of the universe as a whole, so in fact premise 2 is ques-
tionable, since we cannot say whether the order we observe in nature
is typical of the whole. Kant echoes this point at A622“3/B650“1: “We
are not acquainted with the world in its whole content, still less do we
know how to estimate its magnitude by comparison with everything
possible.” In other words, we have no basis for making empirical
claims about the degree of order in the universe or its degree of per-
fection, since we have no standard of comparison. He also criticizes
the idea of an ens realissimum for lacking determinate content. At
A628/B656 he rejects the inference to a divine intelligence, since “the
predicates very great, or ˜astonishing™ or ˜immeasurable power™ and
˜excellence™ do not give any determinate concept at all, and really say
nothing about what the thing in itself is, but are rather only relative
representations” based on a comparison to human attributes.
Both philosophers also formulate a dilemma involved in attempt-
ing to use God™s existence or design as an explanation of the universe.
In part IV of the Dialogues, Hume points out that, for any explana-
tory item (in this case God™s design), either that item requires an
explanation or it does not. If it needs an explanation, then something
else must be the cause of it. On the other hand, if it is permissible
to stop the explanation at that item, then it seems just as permis-
sible to stop it at a prior step, for example, postulating an inherent
order in matter. Thus from the explanatory standpoint, the argu-
ment only adds steps to the series, but does not offer an ultimate
explanation. At A621“2/B649“50 Kant constructs a similar dilemma
for attempts to explain the causal series by an intelligible being. As
he puts it, if one stays within the series of natural causes, then one
cannot cut off the explanation at any point. On the other hand, if
one jumps to the intelligible order, then we are outside the realm of
Transcendental illusion III 281
cognition, which is the only domain in which causal connections
have any signi¬cance.
Moreover, both Hume and Kant point out that it is logically possi-
ble that order could arise from the nature of matter itself, so design is
not the only possible explanation. Hume says in fact that experience
shows that there are other sources of order, such as gravitation, mag-
netism, heat, and so on, which all produce effects in a lawlike fashion.
Kant also cites the failure of the analogy to support the view that God
created the world, certainly a principle of natural theology. As he says
at A626“7/B654“5, “the purposiveness and well-adaptedness of so
many natural arrangements would have to prove merely the contin-
gency of the form, but not of the matter.” That is, the best the proof
can show is that God is “the highest architect of the world . . . but
not a creator of the world, to whose idea everything is subject, which
is far from suf¬cient for . . . proving an all-suf¬cient original being.”
The analogy with human creation, then, can establish at best that the
order in nature is caused by a divine plan, but not that God created
the matter so ordered.
Although Kant questions the inference to a divine architect, he
does not push the analogical reasoning as Hume does. In fact, Hume™s
arguments in part V of the Dialogues are among the most entertaining
in the history of philosophy. Since the success of analogical reasoning
is a matter of degree, depending on how similar the compared items
are, any dissimilarity is a weakness in the reasoning. Hume points out
that, based on our experience of the manner in which humans design
and create machines, the conclusion to a single, in¬nitely perfect
architect of the universe is not warranted. First, as we saw above,
our limited experience gives us no basis for judging the perfection of
the order in the universe. Moreover, since human creation proceeds
by trial and error, this universe could be one in a series of universes
that were discarded as failures. It is also true that human machines
generally result from collaborative efforts. Analogical reasoning, then,
gives better support for the conclusion that the universe was planned
by a committee of imperfect, bumbling designers rather than the ens
realissimum of traditional theology.
Kant ends the chapter by brie¬‚y contrasting two types of theology
based on the idea of the absolutely necessary being. Deism conceives
Transcendental illusion III
of this being only as an impersonal cause of the world; Kant calls this
a mere “transcendental theology” (A631/B659). By contrast, the theist
personalizes this original being as a divine intelligence, the author of
the world. This is the basis of natural theology. Although he rejects
both forms of theology as fruitless speculation, Kant foreshadows
his argument in the Canon of Pure Reason and in the Critique of
Practical Reason that the idea of God as the author of nature is a
necessary postulate of practical reason: “In the future we will show
about the moral laws that they not only presuppose the existence of
a highest being, but also . . . they postulate this existence rightfully
but, of course, only practically” (A634/B662). We shall see how he
develops this point in chapter 11.

5 . su mm a ry
In this chapter, Kant completes his discussion of the transcendental
illusion motivating reason™s search for the unconditioned. In rational
theology, reason attempts to prove the existence of God as the abso-
lutely necessary being conditioning all objects in general. As Kant
sees it, the attempt begins with the logical idea of the collection of
all possible predicates. This “transcendental substratum” for thinking
the real becomes hypostatized as an ens realissimum, a being having
the highest degree of reality. The illusion is completed when this abso-
lutely necessary being is identi¬ed with the ens realissimum, or God.
The proofs mistakenly treat the regulative idea of the ens realissimum
as a concept of a determinate object.
Kant criticizes the three traditional proofs “ the ontological, cos-
mological, and physico-theological arguments “ for embodying this
transcendental illusion. Although the latter two make a posteriori
arguments, Kant believes they implicitly presuppose the validity
of the a priori ontological argument. This occurs in the assump-
tion that the only possible candidate for the absolutely necessary
being is a being with the highest reality. Although thinkers before
Kant made some of his objections, his evaluation of the ontological
argument is noteworthy for anticipating developments in modern
logic. In arguing that existence is not a real predicate of individuals,
Kant foreshadows Frege™s and Russell™s treatment of the existential
Transcendental illusion III 283
quanti¬er as a second-order predicate or propositional function. Thus
Kant makes a signi¬cant contribution, independent of the critical
philosophy, to the debate over the ontological argument. Despite
rejecting claims to theoretical knowledge of God, Kant maintains
that the idea of God is signi¬cant for practical reason, as a founda-
tion for moral faith, as well as a regulative idea promoting empirical
c h ap t e r 11

Reason and the critical philosophy

As we saw in chapter 10, Kant believes the transcendental ideas of
reason perform two positive functions: ¬rst, the idea of the uncondi-
tioned generates regulative principles for scienti¬c explanations; sec-
ond, the ideal of the ens realissimum provides a basis of moral faith for
practical reason. The last part of the Critique sketches an account of
both functions. Despite the brevity of his account here, Kant claims
that reason is essential to the operations of the understanding. In
spelling out this relation, Kant completes his revolutionary theory
of the intellect. As we saw earlier in the Analytic, in analyzing con-
cepts as predicates of possible judgments, Kant overturned the tradi-
tional view that judging presupposes conceiving. Here he completes
the reversal by showing how judgment presupposes the higher-order
functions of reason.
The ¬nal section of the Critique is the Transcendental Doctrine of
Method. Although this contains four chapters, only the ¬rst two offer
substantive discussions. In chapter I, the Discipline of Pure Reason,
Kant contrasts the methods of philosophy and mathematics. The sig-
ni¬cant aspects here concern his theory of mathematical construction,
and his views on de¬nitions, axioms, and demonstrations. In chap-
ter II, the Canon of Pure Reason, Kant outlines the moral theology
required by practical reason, sketching his conceptions of the good
and the morally ideal world. Here he argues that the moral law requires
us to postulate the existence of God and the immortality of the soul.

1. the a ppend ix: th e re gu l ati ve use of rea s on
Kant explains the positive role of transcendental ideas in an Appendix
to the critique of speculative theology. First, he says, “Everything
Reason and the critical philosophy 285
grounded in the nature of our powers must be purposive and con-
sistent with their correct use” (A642/B670). Ideas of reason, then,
must have a positive real function, analogous to their logical use.
This function has two aspects. First, the speculative interest of rea-
son to seek the unconditioned provides the understanding a motive
to inquire into nature. Second, reason supplies methodological prin-
ciples guiding the understanding in creating empirical theories. By
now it is clear that transcendental ideas of reason are regulative only
and not constitutive. Because regulative principles function as imper-
atives rather than assertions, they do not make cognitive claims, but
merely give directions for systematizing empirical knowledge. Despite
their “subjective” character, these ideas have a “necessary regulative
use . . . directing the understanding to a certain goal . . . which,
although it is only an idea (focus imaginarius), . . . serves to obtain
for these concepts the greatest unity alongside the greatest exten-
sion” (A644/B672). Regulative ideas transcend experience and conse-
quently represent only ends to strive for in science, rather than features
of objects. But without them, the understanding could not produce
empirical cognitions, since it would lack a motivation to explain the
phenomena, as well as maxims for proceeding.
At A646/B674 Kant describes reason as the faculty of deriving the
particular from the universal. In logical inferences, the use of reason is
“apodictic,” since the universal is certain and given, and the particular
can be subsumed under it. In its real, explanatory use, by contrast,
reason operates “hypothetically,” by proposing problematic ideas to
¬t the given particulars. Because one can never be certain that the idea
applies to all possible instances, these hypotheses can only approxi-
mate universal rules. In general, the task of reason is to supply unity to
the judgments of the understanding. It does this by “projecting” the
idea of an interconnected whole “ a complete explanation of nature “
as a goal. Kant uses the example of the concept of power: experi-
ence shows that substances have diverse powers. He actually cites the
mental powers, “sensation, consciousness, imagination, memory, wit,
the power to distinguish, pleasure, desire, etc.” (A649/B677). Reason
produces the “logical maxim” to combine these powers under gen-
eral headings, and, ultimately, to seek “a fundamental power” at the
origin of all mental abilities.
But reason supplies more than the stimulus to explain natural
phenomena: in fact the understanding could not function without
Reason and the critical philosophy
reason. In a cryptic comment at A647/B675 Kant says, “The hypothet-
ical use of reason is therefore directed at the systematic unity of the
understanding™s cognitions, which, however, is the touchstone of
truth for its rules.” He remarks below that without the law of reason
there would be “no coherent use of the understanding, and, lack-
ing that, no suf¬cient mark of empirical truth; thus in regard to the
latter we simply have to presuppose the systematic unity of nature as
objectively valid and necessary” (A651/B679). Kant™s point is that the
truth values of empirical judgments can be determined only by testing
them for evidence against a system of empirical judgments. In par-
ticular, empirical generalizations can attain the status of laws only by
being subsumed under higher-order laws. Thus empirical cognition
presupposes both the logical (justi¬catory) and the real (explanatory)
functions of reason. Although the ideas of reason are not constitutive,
they are necessary for the understanding to produce cognitive claims.
In addition to motivating the understanding, reason supplies three
methodological principles guiding scienti¬c inquiry, the logical prin-
ciples of genera, species, and the af¬nity or continuity of forms.
Although all three principles were traditionally recognized as presup-
positions of scienti¬c explanation, until Kant no philosopher offered
a systematic justi¬cation.
The ¬rst, logical principle of genera is known as Occam™s razor,
or the law of parsimony. It was expressed in the “scholastic rule that
one should not multiply beginnings (principles) without necessity”
(A652/B680). In other words, the simpler the explanation, the bet-
ter. Scientists apply the principle whenever they seek commonalities
among diverse forms: here Kant adds to his example of mental pow-
ers the attempt to ¬nd common principles for the varieties of salts
and earths. This requires comparing distinct individuals or species
to identify their common characteristics. Rather than representing
merely an aesthetic value, however, the principle has a transcendental
basis. If this law did not obtain, there could be no empirical concepts:
no concept of a genus, nor any other universal concept, indeed no under-
standing at all would obtain . . . The logical principle of genera therefore
presupposes a transcendental one if it is to be applied to nature . . . According
to that principle sameness of kind is necessarily presupposed in the mani-
fold of a possible experience (even though we cannot determine its degree a
priori). (A653“4/B681“2)
Reason and the critical philosophy 287
That is, if we could not presuppose some degree of unity in expe-
rience, concepts of the understanding would have no application.
Thus empirical concept formation presupposes reason™s maxim to
seek unity in the phenomena.
The second principle aims at completeness through speci¬city.
This “law of speci¬cation” balances Occam™s razor by demanding
subspecies for every species. Like the ¬rst law, the second also has a
transcendental ground in the function of the understanding. For the
logical structure of concepts requires that they be not only subsumable
under higher-order concepts, but also subject to partition into lower-
level concepts. These two laws together constitute a tension in reason,
expressing interests both “in the domain (universality) in regard to
genera” and “in content (determinacy) in respect of the manifoldness
of species” (A654/B682).
Finally, Kant derives from these two principles a third, “the law
of the af¬nity of all concepts.” It postulates “a continuous transition
from every species to every other through a graduated increase of vari-
eties” (A657“8/B685“6). That is, the demands for unity and complete-
ness rule out ending the search for both similarities and differences at
any point. Kant says the principle that “there are no different original
and primary genera, which would be, as it were, isolated and separated
from one another” entails that “intervening species are always possi-
ble, whose difference from the ¬rst and second species is smaller than
their difference from each other” (A659“60/B687“8). This idea was
traditionally expressed as the principle that “nature makes no leaps.”
Recognized by Leibniz, it was most fruitfully expressed as the Law
of Least Action by Pierre-Louis Moreau de Maupertuis (1698“1759).
Maupertuis™s version states that whenever changes occur in nature, the
quantity of action is always the smallest possible, where quantity of
action is proportional to the product of a body™s mass and its velocity
and the distance it travels. Kant explains how the law applies to plan-
etary orbits. If we ¬nd that there are variations in the circular orbits of
planets, “we suppose that the movements of the planets that are not
a circle will more or less approximate to its properties, and then we
come upon the ellipse” (A662“3/B690“1). Although Kant does not
say so explicitly, all three principles formally codify his solution to
the Antinomies, namely that the world of appearances is given only
in the empirical regress. For if appearances do not have their nature
Reason and the critical philosophy
independently of the regress, then one cannot presuppose limits to
the search for genera or species.
These principles enable the understanding to produce empirical
theories and laws explaining the phenomena. From the Analytic, we
know that from its functions the understanding supplies only a priori
concepts such as substance and causality, which are too abstract to
yield empirical concepts. For example, the First Analogy requires that
all events be thought as changes of substance, but leaves the nature
of substance undetermined. Similarly, although the Second Analogy
guarantees the existence of empirical causal laws, it cannot provide
them. From Kant™s cryptic examples, empirical concept formation
involves comparing individuals (or species) and abstracting from their
differences to identify their similarities. (In effect this is the process
empiricists such as Locke thought gave rise to all concepts.) These
similar features then are represented by empirical concepts, which the
understanding orders in genus“species relations.
In the Critique of the Power of Judgment of 1790 Kant takes a
more systematic approach to empirical explanations. In this work
he emphasizes two uses of judgment, determining and re¬‚ective. As
the First Introduction explains, in determining judgment one applies
a given concept to an individual, thereby making a cognitive claim.
In re¬‚ection one is given an individual, and seeks a concept under
which to subsume it.1 Kant assigns both empirical concept formation
and aesthetic judgment to re¬‚ective judgment. The factor unifying
these two accounts is the transcendental principle of purposiveness, to
which Kant alludes in the Appendix and the Canon of Pure Reason.
The remainder of the Appendix emphasizes the regulative nature
of the principles of reason. In places Kant appears to contradict him-
self, sometimes calling them “objective,” and at other times “subjec-
tive.” As Grier points out, however, a charitable reading can resolve
the dif¬culties.2 There are two related senses in which the principles
are “subjective.” First, Kant consistently maintains that they do not
provide determinate concepts of objects, but only guide the under-
standing in securing such concepts. In that sense they lack objective
validity. And second, because they function as imperatives rather than

1 See Critique of the Power of Judgment, 15.
2 See Kant™s Doctrine of Transcendental Illusion, 268“79, for her discussion of this issue.
Reason and the critical philosophy 289
assertions, they serve as “subjective maxims” for this activity: “I call all
subjective principles that are taken not from the constitution of the
object but from the interest of reason in regard to . . . the cognition
of this object, maxims of reason. Thus there are maxims of specu-
lative reason . . . even though it may seem as if they were objective
principles” (A666/B694). Here Kant explicitly compares the princi-
ples of reason to the “subjective” practical maxims on which agents
act. He attributes the subjectivity of both types of maxims to their
origin in the interests of reason. Despite their “subjectivity” as max-
ims, as Grier points out, the principles are “objective” insofar as they
project an object for the understanding, namely a complete system
of cognition. More telling is Kant™s view that the coherent function
of the understanding presupposes both logical and real functions of
reason. Thus the regulative principles of reason are “indispensably
necessary”: without them there could be no determinate cognition of
The Appendix ends with remarks “On the ¬nal aim of the natural
dialectic of human reason.” This adds little, primarily emphasizing
the illusion resulting from misusing regulative principles. Of psy-
chological interest is his analysis of two mental failings: “lazy” and
“perverted” reason. Lazy reason occurs when one takes the idea of
God constitutively, thus bypassing the search for natural causes, “so
that instead of seeking them in the universal laws of the mecha-
nism of matter, we appeal right away to the inscrutable decree of the
highest wisdom” (A691/B719). Perverted reason, similarly, takes place
when one reverses the relation between natural phenomena and the
ideal of systematic unity. Here “the concept of such a highest intelli-
gence is determined anthropomorphically, and then one imposes ends
on nature forcibly and dictatorially” (A692/B720). In assuming that
all natural systems are teleological, one effectively destroys the unity
of nature, making it “entirely foreign and contingent in relation to
the nature of things” (A693/B721).
More substantive are Kant™s views of the relation between the ideas
of God and purposive unity in nature. At A686“7/B714“15 he remarks:
“This highest formal unity that alone rests on concepts of reason is
the purposive unity of things, and the speculative interest of reason
makes it necessary to regard every ordinance in the world as if it had
sprouted from the intention of a highest reason.” Such a principle
Reason and the critical philosophy
opens up “entirely new prospects for connecting up things in the
world in accordance with teleological laws, and thereby attaining to
the greatest systematic unity among them.” And he returns to the idea
at A694/B722, asserting that “Complete purposive unity is perfection”
and that “The greatest systematic unity . . . is . . . the ground of the
possibility of the greatest use of human reason.” Because this idea
“is legislative for us, . . . it is very natural to assume a corresponding
legislative reason (intellectus archetypus) from which all systematic
unity of nature, as the object of our reason, is to be derived.” As I
indicated above, this notion becomes the basis for Kant™s theory of
re¬‚ective judgment in the third Critique, as well as the key to Kant™s
moral theology.

2. t he doc trine of m e th od : th e di sci pl in e
of re a son
Although “discipline,” positively, means a form of instruction, Kant™s
concern here is with the negative sense, as a corrective: “The com-
pulsion through which the constant propensity to stray from certain
rules is limited and ¬nally eradicated is called discipline” (A709/B737
and note at A710/B738). His discussion of transcendental illusion so
far has concerned the discipline of the “content” of reason. Here he
addresses the discipline of the method of pure reason (A712/B740).
He divides the chapter into four sections, of which the ¬rst is the
most important. Kant™s strategy is to criticize the traditional “ana-
lytic” methods of philosophy by contrasting them with the “synthetic”
method of mathematics. In particular, he argues that dogmatic meta-
physicians are mistaken to think that philosophy can attain synthetic
a priori truths having the immediate certainty of mathematical cogni-
tion. Here he both develops the theory of mathematical construction
and presents a sophisticated theory of de¬nition. The remaining sec-
tions discuss the polemical use of reason, and its use with regard to
hypotheses and proofs, emphasizing Kant™s enlightenment attitude
toward knowledge.
Kant™s main point is that the formal methods of philosophy and
mathematics differ because of the nature of their concepts. Although
both employ a priori concepts, philosophical concepts originate in
the understanding, whereas mathematical concepts derive from pure
Reason and the critical philosophy 291
intuition. In consequence, the objects of mathematics can be con-
structed a priori, unlike the objects of philosophy. Corresponding
to this distinction are differences in the status and evidence of their
principles. On Kant™s view, only mathematics begins with axioms,
produces demonstrations, and can succeed in de¬ning its concepts.
Philosophy can produce neither complete de¬nitions of concepts nor
axiomatic principles. Although Kant™s original distinction between
analytic and synthetic judgments depends on the notion of “concept
containment,” in fact neither pure concepts of the understanding nor
empirical concepts can, strictly speaking, be de¬ned.
Kant begins by characterizing philosophical cognition as ratio-
nal cognition from concepts, and mathematical cognition as “from
the construction of concepts.” To construct a concept is “to exhibit
a priori the intuition corresponding to it.” Although this requires
a non-empirical intuition of an individual object, the construction
must “express in the representation universal validity for all possible
intuitions that belong under the same concept” (A713/B741). Mathe-
matical construction represents in pure intuition an individual object,
which, in spite of its particularity, has universal validity. Although the
construction may take place empirically, for example on paper, it need
not, since ¬gures can be exhibited a priori “through mere imagination,
in pure intuition” (A714/B742). Even when the ¬gure is represented
empirically, features such as the actual lengths of sides or sizes of angles
are irrelevant to the spatial relations being represented. In either case
it proceeds a priori, and thus exhibits synthetic a priori propositions.3
It is tempting to think mathematics and philosophy concern
different objects, the former quantity, the latter quality. This is a
mistake, however, since philosophy deals with magnitudes such as
totality and in¬nity, and mathematics concerns qualitative features
such as “the continuity of extension” (A715/B743). The difference
is not in the object, but in the manner of representing it: “only
the concept of magnitudes can be constructed, i.e., exhibited a pri-
ori in intuition, while qualities cannot be exhibited in anything
but empirical intuition . . . Thus no one can ever derive an intu-
ition corresponding to the concept of reality from anywhere except
3 Friedman agrees with Thompson, Parsons, and Brittan that empirical intuition is required
to establish the real possibility of mathematical concepts. It is not, however, required for pure
mathematics. See Friedman, Kant and the Exact Sciences, 101“2.
Reason and the critical philosophy
experience” (A714“15/B742“3). Consider the difference between the
shape and the color of a cone: colors are given only in empirical
intuition, whereas the pure intuition of space affords everything
required to describe the region delineated by a cone. Thus colors
cannot be constructed a priori (although their degree of intensity
can be).
The key is the relation between concepts and their objects. At
A719“20/B747“8 he reminds us that all cognition is ultimately related
to possible intuitions: “for through these alone is an object given.”
Mathematics can construct its concepts a priori because the intuition
of space provides the objects of geometry along with their concepts.4
Philosophical concepts make claims about real properties given only
empirically: “I cannot exhibit the concept of a cause in general in
intuition in any way except in an example given to me by experience,
etc.” (A715/B743). Put technically, the synthetic a priori cognition of
the “thing in general . . . can never yield a priori more than the mere
rule of the synthesis of that which perception may give a posteriori,
but never the intuition of the real object, since this must necessar-
ily be empirical” (A720/B749). So although extensive and intensive
measurements of real properties are constructible in intuition, the
properties themselves are not.
So far we have been treating mathematical construction as if there
were only one kind. In fact Kant distinguishes ostensive constructions
of geometry from symbolic constructions of arithmetic and algebra.
Although the latter also contain synthetic a priori judgments, they
are more abstract, lacking their own object:
But mathematics does not merely construct magnitudes (quanta), as in
geometry, but also mere magnitude (quantitas), as in algebra, where it entirely
abstracts from the constitution of the object that is to be thought . . . In
this case it chooses a certain notation for all construction of magnitudes in
general (numbers), as well as addition, subtraction, extraction of roots, etc.,
and . . . it then exhibits all the procedures through which magnitude is gen-
erated and altered in accordance with certain rules in intuition. (A717/B745)
Friedman explains this clearly.5 First he remarks that, based on Kant™s
theory in the Aesthetic, one would expect time to provide an object

4 Emily Carson emphasizes this point in “Kant on the Method of Mathematics,” 645“51.
5 Kant and the Exact Sciences; see especially 104“14.
Reason and the critical philosophy 293
for arithmetic as space does for geometry. But in fact, numbers are
not temporal “objects,” and arithmetic does not have its own object.
Time comes into play in the science of mechanics: at B49 Kant says,
“our concept of time therefore explains the possibility of as much
synthetic a priori cognition as is presented by the general theory of
motion.” The key is Kant™s distinction between a magnitude as an
object (quanta), and a mere magnitude as a quantity (quantitas).
Friedman says quanta refers to “the particular magnitudes there
happen to be. These are given, in the ¬rst instance, by the axioms
of Euclid™s geometry, which postulate the construction (from the
modern point of view, the existence) of all the relevant spatial mag-
nitudes.”6 In other words, geometry is the science of existing mag-
nitudes given in space. The numerical formulas of arithmetic and
algebra, by contrast, are based on quantity, “the concept of a thing
in general through the determination of magnitude.” Arithmetic and
algebra make no existence assumptions. Rather, their formulas express
“the operations and concepts . . . for manipulating, and thereby cal-
culating the speci¬c magnitude of any magnitudes which happen
to exist.”7 As Kant puts it, symbolic construction “entirely abstracts
from the constitution of the object that is to be thought.” Rather than
presenting the object in intuition, “it chooses a certain notation for all
construction of magnitudes in general (numbers),” and “then exhibits
all the procedures through which magnitude is generated and altered
in accordance with certain rules in intuition” (A717/B745). The for-
mulas of arithmetic and algebra are not principles for constructing
objects, then, but rules for operating with whatever magnitudes are
given in experience.8 As we shall see, Kant also denies these formulas
the character of axioms.
At A718/B746 Kant elaborates two types of spatial (geometrical)
construction. An empirical procedure “would yield only an empir-
ical proposition (through measurement of its angles), which would
contain no universality, let alone necessity.” In the second proce-
dure, “I put together in a pure intuition . . . the manifold that
belongs to the schema of a triangle in general and thus to its concept,
6 7 Kant and the Exact Sciences, 114.
Friedman, Kant and the Exact Sciences, 114.
8 Friedman explains that for Kant, arithmetic is concerned with rational magnitudes, whereas
“algebra is also concerned with irrational or incommensurable magnitudes,” produced by the
extraction of roots. See Kant and the Exact Sciences, 108“12.
Reason and the critical philosophy

b c
Figure 11.1

through which general synthetic propositions must be constructed.”
Lisa Shabel explains his point.9 She argues that the empirical pro-
cedure is modeled in Christian Wolff™s “mechanical” demonstration
of the angle-sum theorem (that the sum of the angles of a triangle
equals 180o ), in his Mathematisches Lexicon. There Wolff constructs
the triangle ABC with angles a, b, c. (See Figure 11.1.)
He then uses a compass to “carry” the arcs describing angles a and
b along the line BD, creating angle a equal to a, and angle b equal to
b. He then concludes that the three interior angles equal 180o . As Sha-
bel explains, this “demonstration” amounts to a measurement of the
interior angles by fallible tools, and depends on visual inspection to
determine equality of the angles. The resulting judgment “is an empir-
ical assessment based on the features of the particular constructed
triangle; the skill of the geometer who ˜carries™ the arcs; and the pre-
cision of the tools used to do so.”10 In consequence, the conclusion
that the interior angles sum to two right angles is only a “metric judg-
ment” concerning a particular empirical triangle, lacking the univer-
sality and necessity required for a mathematical demonstration.
Euclid™s own demonstration, by contrast, represents the a priori
method establishing the necessity and universality of the angle-sum
theorem. In it, the geometer
extends one side of his triangle, and obtains two adjacent angles that together
are equal to two right ones. Now he divides the external one of these angles
by drawing a line parallel to the opposite side of the triangle, and sees that
here there arises an external adjacent angle which is equal to an internal one,
etc. (A716/B744)
9 See Shabel, “Kant™s ˜Argument from Geometry™,” 209“13.
10 Shabel, “Kant™s ˜Argument from Geometry™,” 211.
Reason and the critical philosophy 295
That is, Euclid proceeds by ¬rst extending line BC to D, then con-
structing line CE parallel to line AB. Since AC is a transversal, angle
a is equal to angle a, and since BD is a transversal, angle b is equal
to angle b. Thus the demonstration shows that the interior angles
of triangle ABC are equal to the three angles lying on BCD, and
consequently to two right angles or 180o . As Shabel points out, this
proof depends not on visual inspection or empirical procedures, but
only on the judgment of “containments among spatial regions” which
depends on “prior stipulations for constructing spatial regions,” avail-
able only through the pure intuition of space.11 Thus the diagram rep-
resents only the a priori act, which, Kant says, “considers the concept
in concreto, although not empirically” (A715/B743).
Owing to the constructibility of concepts in pure intuition, “Math-
ematics is thoroughly grounded on de¬nitions, axioms, and demon-
strations” (A726/B754). In all three respects it differs from philosophy,
which, as we have seen, cannot exhibit its objects a priori in intuition.
At A722/B750 Kant characterizes a transcendental proposition of phi-
losophy as “a synthetic rational cognition in accordance with mere
concepts, and thus discursive, since . . . no intuition is given by it
a priori.” Not only can philosophy not demonstrate its propositions
from the mere analysis of concepts, it cannot even provide clear def-
initions of its terms.
The most original part of Kant™s analysis is his theory of de¬nition.
At A728/B756 he contrasts real de¬nition, analyzing the concept of
a thing, with nominal de¬nition, de¬ning a word or “designation.”12
Now “to de¬ne properly means just to exhibit originally the exhaus-
tive concept of a thing within its boundaries” (A727/B755). By con-
trast, the “explication” or “exposition” of a concept merely identi¬es
some marks thought in the concept of a thing. It is no surprise to ¬nd
that empirical concepts cannot be de¬ned exhaustively; not only do
different persons think different marks with respect to the concept,
but an exhaustive analysis depends on experience:
Thus in the concept of gold one person might think, besides its weight, color,
and ductility, its property of not rusting, while another might know nothing
about this . . . And in any case what would be the point of de¬ning such a

11 Shabel, “Kant™s ˜Argument from Geometry™,” 212.
12 See Carson for a helpful discussion of real and nominal de¬nition, “Kant on the Method of
Mathematics,” 648.
Reason and the critical philosophy
concept? “ since when, e.g., water and its properties are under discussion,
one will not stop at what is intended by the word “water” but rather advance
to experiments. (A727“8/B755“6)
Despite their a priori origin, philosophical concepts are also not
de¬nable, because pure concepts of the understanding and reason
are “given” rather than made arbitrarily:
Strictly speaking no concept given a priori can be de¬ned, e.g., substance,
cause, right, equity, etc. . . . But since the concept . . . as it is given, can
contain many obscure representations, . . . the exhaustiveness of the analysis
of my concept is always doubtful, and . . . can only be made probably but
never apodictically certain. (A728“9/B756“7)
Pure concepts arise in the activity of judging, and are “given” as
concepts of synthetic functions. The concepts, like these functions,
are too indeterminate to specify their objects.
This leaves only arbitrary concepts that can be de¬ned, since “I
must know what I wanted to think, since I deliberately made it up,
and it was not given to me either through the nature of the under-
standing or through experience” (A729/B757). But even here there are
limitations, for “if the concept depends upon empirical conditions,”
one cannot be certain that it has an object. For example, my ability to
de¬ne the concept of a spiritual substance does not guarantee its exis-
tence. The only arbitrary concepts that guarantee the existence of their
objects are geometric, precisely because they can be constructed a pri-
ori, “and thus only mathematics has de¬nitions. For the object that it
thinks it also exhibits a priori in intuition, and this can surely contain
neither more nor less than the concept, since through the explana-
tion of the concept the object is originally given” (A729“30/B757“8).
Mathematical concepts are de¬nable because they are constructible
a priori in pure intuition. The form of intuition constrains the arbi-
trariness of the concept, while its construction ensures the existence
of the object. As Emily Carson points out, because construction is a
synthetic process, mathematical de¬nitions are synthetic rather than
analytic.13 On Kant™s view, de¬nition is the beginning point in mathe-
matics, whereas in philosophy, de¬nition “must conclude rather than
begin the work” (A730“1/B759“60).

13 See Carson, “Kant on the Method of Mathematics,” 648.
Reason and the critical philosophy 297
The constructibility of mathematical concepts also confers the sta-
tus of axioms on fundamental mathematical propositions. Axioms
“are synthetic a priori principles, insofar as they are immediately cer-
tain” (A732/B760). Now although philosophy has synthetic a priori
principles, these are discursive, i.e., “rational cognition in accordance
with concepts” (A732/B760). But synthetic judgments are always
based on a “third, mediating cognition,” since they cannot be obtained
from mere concepts. The principle that everything that happens has a
cause, for example, can be justi¬ed only in relation to “the condition of
time-determination in an experience” (A733/B761). For mathematics,
construction in pure intuition allows connecting the predicates both
a priori and immediately (A732/B761). The axioms of geometry are
just the fundamental principles of construction, such as “three points
always lie in a plane” (A733/B761). Kant also remarks that the princi-
ples of extensive measurement labeled the Axioms of Intuition are not
themselves axioms, but principles demonstrating the applicability of
mathematical axioms to objects of experience (A733/B761). Although
he does not say so here, Kant also claims in that section of the Analytic
that arithmetic and algebra lack axioms. There, at A163“4/B204, he
says “the self-evident propositions of numerical relation . . . are, to
be sure, synthetic, but not general, like those of geometry, and for
that reason also cannot be called axioms.” This is related to the view
discussed above, that arithmetic and algebraic formulas are rules for
calculating quantities in general.
Finally, only mathematical principles can be demonstrated. A
demonstration is “an apodictic proof, insofar as it is intuitive”
(A734/B762). Because mathematics derives its cognition from the
construction of concepts, “i.e., from the intuition that can be given a
priori corresponding to the concepts” (A734/B762), its non-axiomatic
principles deserve the title of theorems. As we saw above, philosophi-
cal principles such as the principle of causality cannot be presented in
intuition a priori, but require a transcendental deduction which must
appeal to the necessary conditions of experience. In consequence,
Kant says, philosophical principles should be labeled “dogmata” rather
than theorems (A736/B764). Despite this label, there is no room for
dogmatic methods in philosophy, since the attempt to prove spec-
ulative principles directly “merely masks mistakes and errors, and
deceives philosophy” (A737/B765).
Reason and the critical philosophy
This last point becomes the focus of the second section of the Dis-
cipline of Pure Reason, where Kant argues eloquently for the critical
method based on the autonomy of reason. Just as citizens of a free state
legislate for themselves, the “very existence of reason depends upon
this freedom” (A738/B766), since any external constraint effectively
negates the function of reason. Although reason cannot establish its
claims dogmatically, it can use polemics to defend itself against dog-
matic claims to the contrary. Kant brie¬‚y returns to the worry that
reason could be divided against itself, reminding us that even the
antithetical claims of the Antinomies are not genuine contradicto-
ries, since the transcendental distinction between appearances and
things in themselves dissolves the apparent contradiction. Similarly,
the illusory arguments concerning God and the soul violate the con-
clusion that knowledge is only of appearances. Thus the debates of
dogmatic metaphysics are resolved by the critical power of reason
to correct itself. As for skepticism, Kant reiterates many of his crit-
icisms of Hume, and particularly Hume™s failure to recognize the a
priori contributions of the sensibility and the understanding. Any
parent will appreciate Kant™s clever comparison of dogmatism and
skepticism to the psychological stages of childhood and adolescence:
“The ¬rst step in matters of pure reason, which characterizes its
childhood, is dogmatic. The just mentioned second step is skep-
tical, and gives evidence of the caution of the power of judgment
sharpened by experience.” The critical method characterizes mature
reason, which “subjects to evaluation not the facta of reason but rea-
son itself, as concerns its entire capacity and suitability for pure a
priori cognition” (A761/B789). The ¬nal two sections apply Kant™s
conclusions on the power of reason to the use of hypotheses and

3. th e d octrine of me th od : th e ca non
of pu re re a s on
The last section deserving discussion is the Canon, originally intended
as a metaphysics of morals. A canon is “the sum total of the a priori
principles of the correct use” of cognitive faculties (A796/B824). Here
he places his analysis of theoretical reason in the context of reason
in general, emphasizing the primacy of practical reason. Through a
Reason and the critical philosophy 299
discussion of the interests of reason, Kant sketches his conception
of the highest good, explaining the relations between morality, hap-
piness, and the ideas of God and the immortality of the soul. This
account presupposes the role of transcendental idealism in making
the realm of nature compatible with the demands of the moral law.
In the ¬rst section Kant inquires about the origin of the natural
tendency of reason “to venture to the outermost bounds of all cogni-
tion by means of mere ideas in a pure use” (A797/B825). Assuming
a uni¬ed function and purpose of natural faculties, the highest ends
of reason must be practical, and its theoretical use subordinated to
its practical use. The ¬nal aim of speculation, he says “concerns three
objects: the freedom of the will, the immortality of the soul, and the
existence of God” (A798/B826). But as Kant has shown, theoretical
reason cannot achieve cognition of any of these objects. Empirical
investigation must proceed on the assumptions that all phenomena
are caused, that substances are material, and that the only neces-
sities are changes of phenomenal states in accordance with causal
laws. With respect to speculative reason, these three propositions
are transcendent, that is, “considered in themselves, entirely idle”
Only practical reason can produce “pure laws determined com-
pletely a priori,” having more than merely regulative status, “which
do not command under empirical conditions but absolutely”
(A800/B828). These, of course, are the moral laws, which “concern
our conduct in relation to the highest end.” Thus the ultimate aim
of reason concerns “what is to be done if the will is free, if there is a
God, and if there is a future world.” It follows that “the ultimate aim
of nature which provides for us wisely in the disposition of reason
is properly directed only to what is moral” (A801/B829). In the ¬nal
analysis, because reason itself is a unity, and its highest ends are prac-
tical, the value of theoretical reason resides in its service to practical
Kant next sketches the idea of practical freedom as the capacity to
choose independently of necessitation by sensible impulses or desires.
At A802/B830 he contrasts the animal will (arbitrium brutum), whose
power of choice is causally determined by “sensible impulses,” i.e.,
instincts or desires, with the free will (arbitrium liberum), which can
choose based on a concept of the good. Experience proves that humans
Reason and the critical philosophy
have free will, and can exercise practical freedom, since they can
conceive of an objective good, and evaluate their desires accordingly.
In recognizing the necessity of the moral law, in conceiving how one
ought to act, the human will demonstrates its independence from
natural necessitation and thus practical freedom.
Now at A803/B831 Kant makes the claim discussed in chapter 9,
that the existence of practical freedom does not prove the reality of
transcendental freedom, the power to initiate a series spontaneously,
independent of all causal in¬‚uences. This is because the speculative
question remains, “whether in these actions, through which it pre-
scribes laws, reason is not itself determined by further in¬‚uences, and
whether that which with respect to sensory impulses is called freedom
might not in turn with regard to higher and more remote ef¬cient
causes be nature.” Here in the Canon Kant characterizes practical
freedom “as one of the natural causes, namely a causality of reason in
the determination of the will.” So although transcendental freedom
is “contrary to the law of nature,” it is a problem only for theoretical
reason. We saw in the Fourth Antinomy how transcendental idealism
provides the solution.
In the second section Kant lays out his conception of the highest
good, and the relation between morality and happiness. He begins at
A804“5/B832“3 with the three questions addressing the interests of
1. What can I know?
2. What should I do?
3. What may I hope?
The ¬rst question concerns only speculative reason, and is answered
in the critical theory of knowledge. The second is a question for prac-
tical reason; the third, which “is simultaneously practical and theoret-
ical,” introduces the notion of happiness. De¬ning happiness as “the
satisfaction of all our inclinations,” Kant distinguishes between “prag-
matic” laws aiming at happiness and the moral law, which is motivated
by “the worthiness to be happy” (A806/B834). Whereas pragmatic
laws are empirically based, depending on both the agent™s subjec-
tive inclinations and experience of causal connections, the moral law
“abstracts from inclinations and natural means of satisfying them,
and considers only the freedom of a rational being in general and the
Reason and the critical philosophy 301
necessary conditions under which alone it is in agreement with the
distribution of happiness in accordance with principles.” Thus only
the moral law can be known a priori and commands absolutely.
In the remainder of this section Kant introduces the foundation of
a “moral theology” in order to solve two problems. First is the general
problem of systematic unity mentioned in chapter 10: what guarantees
that the world of nature will permit moral action? The other is how
to provide an incentive to the rational agent to act morally: what
guarantees that doing the right thing will result in happiness? The
solution requires postulating the existence of a morally perfect being,
whose divine wisdom and benevolence ensure the ef¬cacy of moral
action as well as a morally just distribution of happiness in a future
In the ideal moral world, free rational agents all act in conformity
to the moral law. Each action has a “thoroughgoing systematic unity
in itself as well as with the freedom of everyone else” (A808/B836).
Although this intelligible notion abstracts entirely from empirical
conditions, it nonetheless has objective reality as a standard for human
action in the sensible world. Thus it answers the question, “What
should I do?” and so provides a model for worthiness to be happy.
But it does not explain what guarantees that moral choices will be
effective or why one should hope to be happy. The solution to these
problems lies in the “ideal of the highest good” (A810/B838). This
is the idea of a divine intelligence, God, who ensures that the natural
order will be consistent with the moral order, and that those who are
worthy attain the happiness they deserve. Kant says that moral ends
would not be attainable unless some ef¬cient cause determined for
moral conduct “an outcome precisely corresponding to our highest
ends, whether in this or in another life. Thus without a God and
a world that is now not visible to us but is hoped for, the majestic
ideas of morality are, to be sure, objects of approbation and admira-
tion but not incentives for resolve and realization” (A812“13/B840“1).
On Kant™s view, the “complete” good for rational agents requires both
moral conduct and the happiness a worthy agent deserves: neither the
happy immoral agent nor the unhappy moral agent satis¬es our con-
ception of a just world. And, obviously, happiness is not distributed
according to moral worth in the world of appearances. But the moral
law is absolutely necessary. Consequently, to avoid regarding moral
Reason and the critical philosophy
laws “as empty ¬gments of the brain” (A811/B839), the rational agent
must presuppose ¬rst, that moral action is ef¬cacious in the present,
and second, that it will be rewarded in a future life, if not in this
In this moral theology, God is the “single, most perfect, and ratio-
nal primordial being” whose supreme will is the source of natural as
well as moral laws. God has the traditional attributes of omnipotence,
omniscience, omnipresence, and is eternal. Because the systematic
unity of ends requires us to regard the laws of nature as if they were
commands of this divine will, we are also justi¬ed in representing
nature as “a system of ends,” having a purposiveness “inseparably
connected a priori to the inner possibility of things” (A816/B844).
Although we must postulate a divine intelligence as the source of
both natural and moral orders, it is a mistake to regard moral obliga-
tion as grounded in God™s commands: “we will not hold actions to be
obligatory because they are God™s commands, but will rather regard
them as divine commands because we are internally obligated to
them” (A819/B847). Effectively responding to the dilemma in Plato™s
Euthyphro, Kant maintains that we must regard the goodness of moral
action as independent of God™s will, based rather in the conception
of a rational agent.
The Canon ends by characterizing the nature of belief in this moral
theology. First Kant classi¬es different ways of believing or “taking
to be true.” Conviction occurs when belief has objectively suf¬cient
grounds, persuasion when the grounds are only subjectively suf¬cient.
Whereas the former has public validity, allowing “the possibility of
communicating it and ¬nding it to be valid for the reason of every
human being,” the latter has only private validity (A820/B849). This
distinction gives rise to three stages in relation to conviction: “having
an opinion, believing, and knowing” (A822/B850). In having an
opinion, one is conscious that its grounds are both “subjectively as
well as objectively insuf¬cient”; i.e., one cannot defend the view.
Believing occurs when one has only subjectively suf¬cient grounds
which one recognizes as objectively insuf¬cient. Knowing, of course,
requires both subjectively and objectively suf¬cient grounds. Kant™s
point is to differentiate moral and theological belief from theoretical
claims to knowledge. Since theoretical claims allow of objectively
suf¬cient grounds, judgments of theoretical reason make claims to
Reason and the critical philosophy 303
knowledge. But despite Kant™s defense of his moral theology, “no one
will be able to boast that he knows that there is a God and a future
life; for if he knows that, then he is precisely the man I have long
sought” (A828“9/B856“7). Nevertheless, “the belief in a God and
another world is so interwoven with my moral disposition that I am
in as little danger of ever surrendering the former as I am worried that
the latter can ever be torn away from me” (A829/B857). In this way
Kant resists the temptation to con¬‚ate practical assumptions with the
cognitive claims of theoretical reason.

4 . su mm a ry
The ¬nal sections of the Critique “ the Appendix to the Critique of
Speculative Theology and the Transcendental Doctrine of Method “
highlight the positive role of the ideas of reason, and the relation
between theoretical and practical reason. Kant also elaborates his the-
ory of mathematics in his critique of philosophical methods. In the
Appendix, Kant explains the regulative function of theoretical rea-
son in providing both a stimulus and methodological guidelines for
empirical inquiry. This analysis completes his revolutionary theory of
the intellect, rejecting the traditional views that conceiving is prior to
judging, and judging prior to reasoning. In contrasting philosophical
and mathematical methods in the Discipline of Pure Reason, Kant
¬lls in the theory of mathematical construction sketched in the Aes-
thetic. Because mathematical concepts originate in pure intuition,
they allow of a priori construction. As a result, mathematics begins
with de¬nitions, contains axioms, and produces demonstrations of its
theorems. Philosophy, by contrast, operates with discursive concepts,
which cannot be constructed or even de¬ned. As a result, philosoph-
ical principles lack the character of axioms and theorems; they can
be justi¬ed only indirectly, through transcendental deductions. Thus
dogmatic metaphysicians who claim immediate certainty for their
principles are mistaken.
Kant originally intended the ¬nal substantive discussion, in part
II of the Canon, as a metaphysics of morals, parallel to the transcen-
dental doctrine of theoretical reason. Here he argues that experience
proves that humans have practical freedom, the ability to choose inde-
pendently of sensuous impulses and desires. Connecting morality
Reason and the critical philosophy
with the transcendental ideas of reason, he argues that practical free-
dom requires us to postulate the existence of God and the immortality
of the soul, to guarantee that moral action will be effective in the sen-
sible world, and that the morally worthy agent will ¬nd happiness
in a future life. Recognizing the shortcomings of this account, Kant
published the Groundwork of the Metaphysics of Morals in 1785, and
the Critique of Practical Reason in 1788, containing his mature theory
of the autonomy of practical freedom.
Conclusion: Kant™s transcendental idealism

To ¬nish, let us return to the questions raised in chapter 3 about
the coherence and defense of Kant™s idealism. Since in section 4 of
chapter 3 I discussed Kant™s justi¬cation for the non-spatiotemporality
thesis (NST) and the unknowability thesis (UT), here I shall focus
on the consistency of his position. I shall not attempt to survey the
literature, which is far too vast, nor to spell out in detail the prevailing
interpretations. My bibliography contains enough references to point
the reader in the right direction.1 Rather, my aim is to indicate brie¬‚y
what I take to be the most charitable interpretation of Kant™s position,
expanding on my remarks on the B edition Preface in chapter 2.
Beginning with F. H. Jacobi in 1787, the most severe critics claimed
that Kant is not justi¬ed in asserting that things in themselves exist,
and that this claim, along with NST, violates UT. The merit of these
charges, of course, depends on how one interprets the distinction
between appearances and things in themselves. Historically, the two
main contenders have been the “two worlds” and “double aspect”
views. From Kant™s time to the early twentieth century, commentators
favored the “two worlds” view, according to which appearances and
things in themselves are ontologically distinct. This view has generally
lost ground, primarily because it is hard to support textually. If the
two worlds are ontologically distinct, then it is dif¬cult to understand
in what sense appearances are of things in themselves, or how things
in themselves could “ground” appearances. From an internal point of
view, I ¬nd nothing to recommend the “two worlds” interpretation.

1 Chapter 8 of Sebastian Gardner™s Guidebook contains a concise discussion of the different
positions and their strengths and weaknesses. Hoke Robinson also explores the issues in detail
in “Two Perspectives on Kant™s Appearances and Things in Themselves.”

The main competitor, the “two aspect” view, has been most force-
fully defended by Henry Allison, following the in¬‚uential work of
Gerold Prauss.2 It takes seriously Kant™s references to appearances as
of things in themselves, and regards the distinction as marking two
ways of considering objects: as they appear to perceivers, and as they
are independently of them. But because of dif¬culties in explaining
how these “two aspects” are related, many philosophers, and espe-
cially Paul Guyer, have rejected this view.3 More recently, in Kantian
Humility, Rae Langton denies that Kant is an idealist, and offers a
third interpretation. Thus there is no clear consensus on how to read
Kant™s distinction between appearances and things in themselves.
My own view developed out of my defense of NST in Space and
Incongruence, where I traced Kant™s idealism to the development of
his critical theory of space. Since then I have found Allison™s read-
ing largely persuasive, and so I classi¬ed my position under the “two
aspect” interpretation. But some recent literature suggests that I may
be mistaken, since my position is similar to alternatives Sebastian
Gardner and Hoke Robinson distinguish from the “two aspects”
view.4 In any case, here I shall simply outline the approach offer-
ing the most charitable account of the critical philosophy.
The Prefaces to the Critique indicate that the distinction between
appearances and things in themselves arises by critical re¬‚ection on
some (pre-re¬‚ective) axioms basic to philosophy. These are:
1. Something exists that has an intrinsic nature of its own.
2. Cognition (representation) is a relation between a subject and an
3. In sensation human subjects are affected by existing things.
As we saw in chapter 8 on the Amphiboly, one pair of concepts
reason employs in transcendental re¬‚ection is the distinction between
the inner and the outer: “In an object of the pure understanding
only that is internal that has no relation (as far as the existence is

2 See Allison™s recently revised Kant™s Transcendental Idealism, chapters 2 and 3, as well as
“Transcendental Idealism: The ˜Two Aspect™ View.”
3 See Kant and the Claims of Knowledge, chapter 15.
4 See Gardner™s discussion of the “indeterminacy” view at Guidebook, 295“8; Robinson also
distinguishes a “two Perspectives” position from the “two aspect” view, “Two Perspectives on
Kant™s Appearances and Things in Themselves,” at 428“32.
Conclusion 307
concerned) to anything that is different from it” (A265/B321). I take
this to be the basis of Kant™s distinction between things in themselves
and appearances. Things in themselves are whatever exists (taken
collectively) considered non-relationally. Appearances are this same
collection in their relation to human subjects. These de¬nitions are
neutral with respect to idealism and realism. Transcendental realists
maintain that perceptual or other cognitive processes give access to
things in themselves, so that, to some extent, appearances represent
things in themselves. Transcendental idealists deny that humans have
such access; although appearances are of things in themselves, they
do not represent them. I agree with Allison and Gardner that Kant™s
idealism results primarily from his doctrine of sensible intuition, and
secondarily from the theory of discursive judgment. These analyses
lead Kant to conclude that objects of human intuition are not things
in themselves, but only appearances.
This explains why at Bxxvi“xxvii Kant says it is absurd to think
there could be appearances without anything that appears (cited in
chapter 2). The absurdity is in maintaining that anything could exist
without an intrinsic, non-relational nature (whether known or not).
In Kant™s critical terms, this is equivalent to the absurdity that the
conditioned (appearance) can exist without its conditions (the thing
in itself ). The view that things in themselves are the non-relational
conditions of existing things as they appear to human perceivers pro-
vides no basis for a “two worlds” interpretation. Kant recognizes,
however, that “there may even be beings of understanding to which
our sensible faculty of intuition has no relation at all” (B308“9). That
is, it is entirely possible that some things in themselves do not appear
to humans, e.g., God.5 But given UT, this possibility lacks cognitive
The next questions are how appearances relate to things in them-
selves, and how to understand the notion of “affection.” Kant™s theory
of intuition depends on axiom 3: sensation arises through outer sense
insofar as external things affect the subject. It is natural to construe
this as a relation between the subject in itself and things in themselves.
In Kant und das Ding an sich, Erich Adickes developed this interpre-
tation as the doctrine of “double affection.” As Gardner explains, on

5 See Gardner, Guidebook, 294“5.
this view “the subject is originally affected transcendentally by things


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