Kant’s Copernican revolution
Kant’s Copernican revolution
Daniel Bonevac
Immanuel Kant’s Critique of Pure Reason was to transform the
philosophical world, at once bringing the Enlightenment to its highest
intellectual development and establishing a new set of problems that would
dominate philosophy in the nineteenth century and beyond. As Richard
Rorty has observed, Kant would turn philosophy into a profession, if for no
other reason than that, after 1781, one could not be called a philosopher
without having mastered Kant’s first Critique—which, in the words of
Kant’s famous commentator, Norman Kemp Smith, “is more obscure and
difficult than even a metaphysical treatise has any right to be.”1
The Critique’s central character is “Human reason,” which, Kant
begins his first edition’s preface by noting,
has this peculiar fate that in one species of its knowledge it is
burdened by questions which, as prescribed by the very nature of
reason itself, it is not able to ignore, but which, as transcending all
its powers, it is also not able to answer.
(A vii)2
Reason develops principles to deal with experience; within the realm of
experience, those principles are well justified. Reason finds itself driven,
however, to ask questions extending beyond that realm. The very
principles it has developed and upon which it properly continues to rely in
dealing with experience there lead it “into darkness and contradictions”
(A viii). Metaphysics, once Queen of the Sciences, now surveys the
battlefield on which these principles clash and mourns. Kant’s aim in the
Critique is to rescue metaphysics, “to secure for human reason complete
satisfaction” (A 856, B 884) by defining its proper sphere of application.
Kant’s means for achieving this end is the critical method. The title of
the work is ambiguous in both English and German: Pure reason may be
the agent or the object of the critique.3 In fact, it is surely both. The
critical method requires reason to critique itself, to determine its own
limits, and then to devise rules for staying within them. This, Kant thinks,
is the key to reason’s “complete satisfaction”: “there is not a single
metaphysical problem which has not been solved, or for the solution of
which the key at least has not been supplied” (A xiii).
Understood in this way, Kant’s critical method hardly seems
revolutionary. It had been exemplified already in Locke’s Essay concerning
Human Understanding and Hume’s Treatise of Human Nature. Both were
attempts to define the limits of human knowledge by employing reason in
a reflective act of self-criticism. Kant’s most important contribution is not
the general idea of the critical method, but the specific form that method
takes, for which he often uses the adjective transcendental rather than
critical. Kant claims that he uses the transcendental method and
establishes the truth of transcendental idealism.
What, then, is the transcendental method? To understand it, we need to
focus on what, in the preface to the second edition of 1787, Kant
considers the key to his advance: his Copernican revolution in philosophy.
“[T]he procedure of metaphysics,” Kant writes, “has hitherto been a
merely random groping, and, what is worst of all, a groping among mere
concepts” (B xv). Kant finds himself capable of setting metaphysics upon
the secure path of a science by advancing a hypothesis analogous to that
of Copernicus.
Hitherto it has been assumed that all our knowledge must conform
to objects. But all attempts to extend our knowledge of objects by
establishing something in regard to them a priori, by means of
concepts, have, on this assumption, ended in failure. We must
therefore make trial whether we may not have more success in the
tasks of metaphysics, if we suppose that objects must conform to our
knowledge.
(B xvi)
Copernicus explained the motions of the heavenly bodies as resulting,
not just from their own motion, but also from the motion of the
observers on earth. Just as he sought “the observed movements, not in
the heavenly bodies, but in the spectator” (B xxii n.), so Kant seeks the
laws governing the realm of experience not in the objects themselves but
in us: “we can know a priori of things only what we ourselves put into
them” (B xviii).
THE PLATONIC HERITAGE
Kant is a rationalist. We might define a concept rationalist as one who
believes in innate concepts—that is, that we have first-order cognitive
abilities that we do not derive from experience—and a judgment
rationalist as one who believes that we can know some synthetic truths a
priori that is, that we can know independently of experience some truths
that are not merely linguistic or verbal, that are not automatically true or
false because of the meanings of the words that constitute them. Kant is
plainly a rationalist in both senses. He argues that we can deduce pure
concepts of the understanding a priori, independently of experience, from
the mere possibility of experience, and moreover that there are synthetic a
priori truths—that is, truths that we can know independently of
experience but that are not merely verbal. Indeed, the establishment of
rationalism in both senses seems to be a major goal of the Critique.
Like many rationalists, Kant understands himself as working within the
Platonic tradition. The central problems he attacks and his solutions to
them stem directly from that tradition. To understand Kant’s Copernican
revolution, therefore, we must consider the framework in which his
thought is embedded.
Consider a judgment of perception, for example, (said pointing to a
figure drawn on a blackboard) ‘This is a triangle.’ According to Plato, at
one very influential stage of his thought, at least, the mind so judging is
Janus-faced. It is turned toward a perceptual object, a triangle, if it judges
correctly. It is also turned toward the abstract form of a triangle. Both the
object and the form have real causal or explanatory power. The object is
causally responsible for our perception of it. But we are able to perceive it
as a triangle because we apprehend the general form of triangularity. The
form of a triangle is exemplified in the triangle itself, which in turn is an
instance of, or, in Plato’s technical language, participates in, the form.
The forms constitute the most distinctive feature of Plato’s philosophy
of mind. They explain our ability to think general thoughts; they account
for regularities as well as changes in experience; they explain how
different people (or the same person at different times) can think the same
thought; and they explain how thoughts can be veridical. We may think
general thoughts, for example, by thinking about the forms and how they
relate. Regularities in experience involve constant relations of forms;
changes occur when an object of sense stops participating in one form and
begins participating in another. Two different people can think the same
thought by attending to the same forms. Finally, thoughts can depict
reality accurately by involving the forms that are actually instantiated.
But the forms also generate a serious epistemological puzzle. By
definition, the forms are not themselves objects of experience; we do not
perceive triangularity as we perceive individual triangles. How, then, do
we know anything about them? How is the realm of forms, which Philo of
Alexandria later termed “the intelligible world,” intelligible? In an
Aristotelian philosophy of mind, we generate our own general concepts
from experience through a process of abstraction. A Platonist may borrow
this account for certain general concepts, but cannot use it for all, because
it is central to Platonism that some forms are ultimately responsible for
our abilities to think the corresponding thoughts. On Plato’s view, we do
not abstract the idea of a pure triangle from triangular objects we
perceive; indeed, we never encounter a pure triangle in experience.
Instead, we recognize objects as triangular because we apprehend the form
of pure triangularity and recognize that the objects approximate that pure
form. In this sense, the forms have causal power; we are able to think of
things as triangular by virtue of our apprehension of the form.
Unfortunately, Plato has no theory that explains our interaction with
the forms. He relies on two metaphors. In the Meno, he speaks of
recollection; we apprehend the forms by recalling a time before birth when
our souls were united with them. In the Republic, he speaks of the form of
the Good as analogous to the sun, shedding light on the realm of forms
and making possible our apprehension of them. Neither metaphor yields a
satisfactory theory within the limits of Platonic metaphysics. Neither,
moreover, seems to explain our apprehension of forms without begging
the question. The Meno metaphor explains the causal efficacy of the forms
now by appealing to their efficacy at some earlier time; the Republic
metaphor, by appealing to the efficacy of the form of the Good. The
Neoplatonic theory of emanation, according to which the entire realm of
forms is ordered, with the causal efficacy of higher levels making lower
levels possible and intelligible, does little to change the central
epistemological difficulty.
Augustine, however, solves Platonism’s epistemological problem by
going beyond the resources of the original theory. To put it crudely, he
adopts the Republic’s solution, but replaces the form of the Good with
God. It is not clear why the form of the Good should be more causally
efficacious than any other form. Causal efficacy, in contrast, is not a
problem for God, who can do anything. Augustine thus follows Philo in
identifying the forms with ideas in the mind of God, and describes the
process by which we apprehend the forms as illumination, an act of
revelation by which God allows us to make use of a portion of divine
mental resources and by which, therefore, God makes our minds resemble
the divine mind. We have innate cognitive capacities that reflect the
principles according to which God created the world.
Platonism remained Augustinian throughout the medieval debates
concerning realism and nominalism arising from the conflict between
Platonic and Aristotelian theories of substance and knowledge. Descartes,
however, advanced a new kind of skeptical argument that forced a change
in Platonism and that brought the theory of knowledge to center stage in
modern philosophy. He added to the traditional arguments of Sextus and
Cicero the possibility of an evil deceiver, who systematically misaligns our
minds to reality. This extends farther than traditional skeptical arguments,
for it raises the possibility that not only sensible knowledge but even logic
and mathematics might be mistaken. It thus challenges the Augustinian
solution to Platonism’s epistemological problem. Why should illumination
produce veridical knowledge? Why should we believe that God reveals the
portion of the divine mind relevant to the construction of the world, and
not some counterfeit of it? Why should our innate ideas, and the a priori
knowledge arising from them, have anything to do with the world?
Kant sees the force of this difficulty, and thinks that, within the Platonic
framework, it is insoluble. He divides previous philosophers into
dogmatists and skeptics (A ix; A 856, B 884). Dogmatists like Descartes
and Leibniz assume that human reason can comprehend ultimate reality.
Their dogmatism involves three factors:
1 Realism. Human thought can discover the nature of objective reality.
2 Transcendence. Real knowledge is capable of extending beyond
experience to the supersensible. (See A 295–6, B 352.)
3 Rationalism.4
Descartes, for example, tries to demonstrate that God guarantees the
veridicality of our a priori judgments by arguing that God exists and is
entirely good. A good God, surely, would not be a deceiver. Granting
Cartesian rationalism, we may see the problem generated by the possibility
of the evil deceiver as precisely that of realism: Why should we believe that
our thinking can discover the nature of objective reality? Descartes’s
solution relies on transcendence. We may take the form of thought implicit
in the cogito, namely, the method of clear and distinct ideas, and apply it
beyond the realm of our own thinking to reality—indeed, to reality that
transcends all possible experience. But this, Kant sees, is just what is at
issue. If realism is false—if our minds cannot discover the nature of
objective reality—then why should we expect our modes of thinking,
applied to the nature of that reality, to be reliable? It will not do to appeal to
transcendence to justify realism, for the only argument for transcendence
presupposes realism. For example, Descartes’s third Meditation, arguing for
the existence and moral excellence of God, appeals to the premise that there
is at least as much reality in the cause as in the effect.5 Why, given only the
certain knowledge that I think and I exist, should I accept this principle as
certain? Descartes derives it by applying the method of clear and distinct
ideas beyond the mental realm of the cogito, which first justified it, to the
realm of external, objective reality. Kant, for this reason, among others,
rejects Descartes’s proof. But his reasoning is broader. Any argument for
realism within the dogmatist’s framework will rely on transcendence and
make a similarly illegitimate move.
Skepticism, as Kant conceives it, also involves three factors:
1 Subjectivism. Knowledge of objects reduces to knowledge of sense.
2 Immanence. Real knowledge is limited to the sphere of sense
experience.
3 Empiricism. (The denial of rationalism in either of its forms.)
Skepticism, too, encounters difficulties. If dogmatism extends our
knowledge too far and too uncritically, skepticism seems unable to
account for the knowledge we do have. Hume’s scandal of induction, for
example, illustrates that we cannot justify any causal knowledge we claim
to have. It would have to reduce to a knowledge of items directly
presented in sensation, but, as Hume shows, it does not.
Kant’s critical philosophy shares the immanence of skepticism, but also
the rationalism of dogmatism. It transcends the distinction between
realism and subjectivism, holding that in a sense each is correct. Kant’s
synthesis of dogmatism and skepticism comes at the cost of distinguishing
between the world of appearance—the phenomenal world—and the world
of things-in-themselves—the noumenal world. The former is essentially
sensible, and human thought can discover its nature. Things-inthemselves,
in contrast, lie beyond our cognitive capacities. The dogmatist
is right about the possibility of knowledge of objects, even a priori
knowledge of them; the skeptic is right about the limitation of knowledge
to the realm of experience.
Both, however, misunderstand the status of objects of experience,
thinking that they are in themselves as they appear to us. The phenomenal
world is both sensible and knowable; the noumenal world is neither. With
respect to phenomena, therefore, the skeptic is vanquished; we can have a
priori knowledge of objects of experience. With respect to noumena,
however, the skeptic triumphs, for we can have no knowledge of things-inthemselves.
Kant’s solution to the epistemological problem of Platonism goes
beyond the distinction between phenomena and noumena. It would be
easy to build that distinction into Descartes’s metaphysics, for example,
without thereby making any headway on the skeptical problem. The key
to Kant’s solution resides in two additional changes to the traditional
framework. First, Kant explains the causal efficacy of the forms by
transforming them into categories, pure concepts of the understanding.
They are innate cognitive capacities of a very general kind, but they are
wholly mental; the question of their correspondence to abstract, mindindependent
forms cannot arise. Without such forms there remains, of
course, the possibility that the categories do not correspond to objective
and concrete reality. So, second, Kant reverses the traditional conception
of the relation between thought and its object, or, as he puts it, between
object and concept. The Platonist traditionally sees the object as causally
responsible for the veridical, perceptual thought of it. Kant’s Copernican
revolution is precisely to reverse this understanding, maintaining instead
that thought is causally responsible for constituting the object. The result
is not anarchy, a circumstance of “thinking making it so,” for the
constitution of objects proceeds according to the categories in a rulegoverned
way. The rule-governed character of the construction makes
knowledge of objects possible. More, it makes a priori knowledge of them
possible, for we can understand what we put into them—we can discover
the rules according to which we constitute them. In this way Kant justifies
his realism with respect to the phenomenal world without any appeal to
transcendence—indeed, in the face of its outright denial.
THE CATEGORIES
Kant’s first change to the traditional Piatonistic framework is to substitute
for the forms the categories, pure concepts of the understanding. These are
innate ideas of the kind smiled upon by every concept rationalist. But
there is no abstract realm of forms to which they must correspond. Their
independence dissolves the epistemological difficulty arising for the aspect
of the mind turned toward the forms in Platonic theories of mind.
All knowledge, Kant observes, involves concepts; all concepts, in turn,
“rest on functions,” “bringing various representations under one common
representation” (A 68, B 93). The representations united in a concept may
be sensible intuitions or other concepts. Kant here makes an important
concession to empiricists such as Hume: the content of concepts traces
ultimately to sensation. Kant makes much of this in the Transcendental
Dialectic to refute the transcendence thesis. In deriving the categories,
however, he focuses on the mediate character of concepts. Concepts of
objects always relate to those objects indirectly:
Since no representation, save when it is an intuition, is in immediate
relation to an object, no concept is ever related to a concept
immediately, but to some other representation of it, be that other
representation an intuition, or itself a concept. Judgment is therefore
the mediate knowledge of an object, that is, a representation of a
representation of it.
(A 68, B 93)
This has the consequence, critical to the Copernican revolution Kant
means to effect, that both judgments and objects are products of synthesis.
Knowledge, Kant contends, always takes the form of judgments. (This is
true at least for discursive knowledge, that is, knowing that, as opposed to
knowing how or knowing to.) Judgments are combinations of concepts,
which, in turn, are rules for synthesis, bringing together various sensations or
concepts. Concepts relate to objects because they are such functions of
synthesis. To discover the pure concepts of the understanding, therefore, we
must find the functions of synthesis with a priori rather than empirical origins.
The content of judgments, we might say, always has an empirical
source, for the content of the concepts that comprise them arises
ultimately from sensation. A concept unites sensible intuitions or other
concepts that themselves unite sensible intuitions or other concepts. The
chain cannot proceed to infinity; at some point, it terminates in intuition.
This may suggest that there are no pure concepts. But not all functions of
synthesis operating in a judgment comprise part of its content. A judgment
has both a content and a form. The content stems from experience, but the
form does not. We can identify the pure concepts of the understanding,
then, by examining the forms of judgment. Fortunately, there is already a
science that abstracts from the content of judgments and examines only
their forms—logic.6
Kant, using Aristotelian logic, derives the following table of judgments
(A 70, B 95):
Every judgment, Kant contends, has a quantity, a quality, a relation, and a
modality. In quantity, it is either universal (‘every metal is a body,’ for
example), particular (‘some metals are yellow’), or singular (‘Socrates is a
philosopher’). In quality, it is either affirmative (‘Socrates is mortal’),
negative (‘Socrates is not mortal’), or infinite (‘Socrates is immortal’). In
relation, judgments may be categorical (‘gold is a metal’), hypothetical (‘if
every metal is a body, gold is a body’), or disjunctive (‘gold is a metal or a
rare earth’). And, in modality, judgments are problematic (‘gold may be a
metal’), assertoric (‘gold is a metal’), or apodeictic (‘gold must be a
metal’). The table of judgments thus gives what Kant takes to be an
exhaustive account of the forms of judgment.
From the perspective of modern logic, the table seems incomplete. It
does not include the quantity of ‘most metals are heavy’ or ‘many metals
oxidize’; it omits the modality of ‘Socrates ought to avoid hemlock.’ It has
no place for judgments with complement clauses, such as ‘Socrates knew
that the hemlock would kill him,’ and makes no provision for the
abstraction relating ‘kind’ and ‘kindness,’ ‘friend’ and ‘friendship.’ It is
silent about verb tense and aspect. (Kant considers time a form of
sensibility, not of judgment, and so considers it beyond the province of
logic.) It omits identity. Kant’s table is not only incomplete from a modern
point of view; it is redundant. Many entries can be derived from others
with the help of forms recognized by contemporary logicians. There is no
consensus on exactly what such a table would need to reflect all the forms
of possible judgment. Kant is surely correct, however, that what we now
call quantifiers, connectives, and modalities are required.
The functions of judgment are not themselves the pure concepts of the
understanding, but they correspond to them one-to-one. Kant lists the
pure concepts of the understanding in his table of categories (A 80, B 106):
Some of these relate directly to a corresponding entry in the table of
judgments—‘Negative’ and ‘Negation,’ for example, or ‘Problematic’ and
‘Possibility—Impossibility.’ Other connections—‘Disjunctive’ and ‘Of
community,’ for instance—seem tenuous. How does Kant derive the table
of categories? His detailed arguments are not terribly important, for, as we
have seen, the entries on the table of judgments reflect an outdated logic.
But it is important to understand what the categories are.
Roughly speaking, what the table of judgments is to judgments, the
table of categories is to objects. Just as the table of judgments outlines the
possible logical forms of judgment, so the table of categories outlines the
possible logical forms of objects. This explains, for example, why,
corresponding to the assertoric modality, we find ‘Existence-nonexistence’
rather than Truth-falsehood.’ Synthesis of the manifold of intuition is
essential to concepts. But synthesis alone does not suffice for knowledge.
Knowledge of objects requires a unification of the pure synthesis of the
sensible manifold. That is, the concept of an object is special: It is the
concept of a unified thing. In different terminology, concepts of objects not
only tell us when a certain predicable or general term applies, but also
when it is being applied to one and the same thing.7 The pure concepts of
the understanding “apply a priori to objects of intuition in general” (A 79,
B 105); they spell out the possible forms of such objects by indicating the
possible kinds of unity.
Kant’s key assumption in deriving the categories in this way is that
“The same function which gives unity to the various representations in a
judgment also gives unity to the mere synthesis of various representations
in an intuition” (A 79, B 105). Each such unity is a pure concept of the
understanding. Why are the unifying functions in judgments and objects
the same? We have seen above that judgments and objects are both
products of synthesis. Moreover, knowledge is always knowledge of
objects through judgments. This suggests that judgments, at least of the
sort appropriate to knowledge, are possible only by virtue of the unifying
activity of the categories. Still, this does not suffice to establish the identity
of function. It shows that the unifying activity in a judgment presupposes
the unifying activity in an intuition, not that they have the same form.
Kant’s argument turns on his notion of a concept. The unity of
judgments and objects alike is a unity in a concept. This not only explains
the link between the table of judgments and the table of categories; it also
explains why the pure concepts of the understanding have a priori validity,
avoiding the challenges of the skeptics.
Concepts of objects in general thus underlie all empirical knowledge
as its a priori conditions. The objective validity of the categories as a
priori concepts rests, therefore, on the fact that, so far as the form of
thought is concerned, through them alone does experience become
possible. They relate of necessity and a priori to objects of
experience, for the reason that only by means of them can any object
whatsoever of experience be thought.
(A 93, B 126)
To understand the role that concepts play in Kant’s theory of mind,
however, we must examine his account of the kinds of synthesis.
THE SUBJECTIVE DEDUCTION
Kant’s argument for the first key to his solution to the problems arising
from the Platonic framework—the pure concepts of the understanding—
also defends and develops the second key, the Copernican revolution. The
argument occupies the portion of the Critique he entitles “The
transcendental deduction of the pure concepts of the understanding.”
There are, however, two very different versions of this argument in the
first and second editions of the Critique. The first edition version presents
a model of how the mind constructs objects from the data of sense,
arguing that the pure concepts of the understanding are essential to the
process. The second version presents no model, but analyzes the
implications of the “I think.” The general strategy, however, remains the
same. The categories are “concepts of an object in general” (B 129); they
are “a priori conditions of the possibility of experience” (A 94, B 126). We
are able to experience objects, that is, only because we have the concept of
an object. We do not derive this concept from experience, for we could not
experience anything as an object without already having the general
concept of an object.
The transcendental deduction of the first edition is notoriously difficult;
Kant apparently pieced it together from four manuscripts composed at
different times and reflecting four different stages of his thinking.8 It
moreover includes two arguments: an “objective” deduction seeking to
establish “the objective validity of a priori concepts,” and a “subjective”
deduction investigating “the faculty of thought” (A x–xi).
The subjective deduction outlines a three-part model of mental
activity—specifically, of the generation of a judgment of experience such
as ‘This is a triangle.’ This model shows, in Kant’s view, how judgments of
experience require the categories. Kant defines a pure concept of the
understanding as a concept without any empirical content, that is, as one
that “universally and adequately expresses…a formal and objective
condition of experience” (A 96). His strategy is to “prove that by their
means alone an object can be thought” (A 97). This, he says, “will justify
their objective validity,” for, if the categories are necessary conditions of
experience, nothing could be an object of experience without complying
with the categories.
Sensation, Kant holds, is a manifold. It bombards us with a plethora of
possible sources of information. Out of this multiplicity we synthesize
representations, concepts, and judgments. The first act of synthesis is that
of apprehension in intuition. All sensations occur in time.9 We bind the
multiplicity sensation offers into unified items of sense. A sensation of a
triangle, for example, may consist of various visual and tactile impressions
received over a short interval of time. We experience it as a single
sensation, usually without being aware of its complex nature. In short, we
organize the data of sense into discrete sensations. This organization is the
synthesis of apprehension in intuition.
The second act is the synthesis of reproduction in imagination. Kant
argues that “experience as such necessarily presupposes the reproducibility
of appearances” (A 101–2). His premises concern pure intuitions of space
and time—drawing a line in thought, for example, or thinking of a
number—which, he maintains, are possible a priori. Kant’s theory of pure
intuitions is controversial and somewhat obscure. But we can argue the
point on other grounds. Sensations, considered individually, are not fullblown
objects of experience. We can have many sensations of the same
object. We might view a triangle, for example, from many different
perspectives. To make any judgment about such an object of experience,
we must relate sensations to each other, being capable of recognizing them
as sensations of the same object. How we do this is of course an empirical
question. But do it we must if we are ever to form concepts of objects of
experience.
That brings us to the third act, the synthesis of recognition in a concept.
Throughout this discussion, Kant seems to operate with two ideas of what
concepts are. The awareness of the unity of various sensations, Kant says,
is a concept—etymologically, a “thinking together.” Having related
sensations in the synthesis of reproduction in imagination, we form a
concept through our consciousness of their unity as an object. But Kant
also speaks of a concept as a rule: “a concept is always, as regards its
form, something universal which serves as a rule” (A 106). Specifically, a
concept is a rule for the synthesis of the manifold of intuition. These two
notions of concepts are intimately connected:
the unity which the object makes necessary can be nothing else than
the formal unity of consciousness in the synthesis of the manifold of
representations. It is only when we have thus produced synthetic
unity in the manifold of intuition that we are in a position to say that
we know the object. But this unity is impossible if the intuition
cannot be generated in accordance with a rule by means of such a
function of synthesis as makes the reproduction of the manifold a
priori necessary, and renders possible a concept in which it is united.
Thus we think of a triangle as an object, in that we are conscious of
the combination of three straight lines according to a rule by which
such an intuition can always be represented. This unity of rule
determines all the manifold, and limits it to conditions which make
unity of apperception possible.
(A 105)
Essential to recognizing something as an object, then, is a consciousness of
its unity. But this consciousness is possible only if the object is constructed
according to a rule. We can recognize a collection of intuitions as
constituting a single object only by having a rule for uniting them into that
object. We take a triangle as a single object rather than three distinct line
segments that happen to intersect because we have a rule for uniting those
segments. Without such a rule, we would be left with a manifold. The two
notions of concept are connected, then, in that we are aware of unity
(concept in sense one) according to a rule (concept in sense two).
The rule-governed character of object construction brings with it a kind
of necessity. To count as a triangle, for example, something must be a
plane figure with three sides and three angles. So, it is a necessary truth
that triangles have three sides and three angles. This, it might seem, is not
the sort of necessity that interests Kant; ‘triangles have three angles’ is
analytic. But when we ask what necessary truths stem, not from the rule
for constructing triangles or any other kind of object, but from the rulegoverned
constructions of objects in general, we obtain a more interesting
answer. All objects must be unified, for example; the concept of an object
is the concept of a single thing.
Necessity, in turn, implies transcendental conclusions about our
contributions to objects.
All necessity, without exception, is grounded in a transcendental
condition. There must, therefore, be a transcendental ground of the
unity of consciousness in the synthesis of the manifold of all our
intuitions, and consequently also of the concepts of objects in
general, and so of all objects of experience, a ground without which
it would be impossible to think any objects for our intuitions.
(A 106)
Kant’s argument begins with the premise that necessity is grounded in a
transcendental condition. He does not argue for it because he takes it as
evident from Hume’s writings. Necessary connections, Hume observes,
cannot be found in experience. We are directly aware of a succession of
things but not of the connections between items of the sequence. (In Frank
O’Malley’s words, “Life is just one damned thing after another.”) Our
concept of necessity, Hume concludes, must come from us, not from what
we experience. So far, Kant agrees. But Hume goes on to attribute the
source of our concept of necessity to the passionate side of our nature, to
a feeling of expectation. Kant, in contrast, finds necessity’s source in the
unity of objects. We experience objects, not just a whirling mass of
sensations. And, as we have seen, it is a necessary truth that all objects are
unified. Kant concludes that there is a transcendental ground of that unity.
The source of the unity of objects, moreover, is also the source of the
concept of an object in general; it thus underlies our experience of any
object.
The transcendental ground of the unity Kant terms transcendental
apperception. When we reflect on the contents of our own consciousness,
as Hume stresses, we are aware only of a succession of mental states; we
do not confront a unified self. The contents of consciousness are always
changing: “No fixed and abiding self can present itself in this flux of inner
appearances” (A 107). Thus, we find no unity in what Kant calls empirical
apperception or inner sense. But there must be a ground of unity in us.
This brings us to Kant’s key contention: The ground of the consciousness
of unity is the unity of consciousness. The source of our consciousness of
the unity of objects is the underlying unity of our consciousness itself. This
unity of apperception is “the a priori ground of all concepts” (A 107), for
all concepts unify the manifold of sensibility into objects. The most
general concepts, relating to the form of an object in general, are the
categories. The unity of apperception and with it the categories underlie
the lawlike connections we find among objects of experience and the
synthetic a priori knowledge we have of them.
The subjective deduction, then, means to spell out Kant’s Copernican
revolution in subjective detail. We can know certain truths about objects
independently of experience, for we can uncover the pure concepts of the
understanding relating to the form of an object in general. These concepts
do not arise from experience; they underlie the possibility of experience.
So, we can know a priori that any experience will conform to them. This
establishes realism, the view that we can attain knowledge of objective
reality, within the realm of objects of experience. It also establishes
concept rationalism. Most importantly, it solves the traditional Platonic
problem of the conformity of the world to our innate ideas without
invoking God, ex caelo or ex machina.
THE OBJECTIVE DEDUCTION
Kant nevertheless views the subjective deduction as inessential to the success
of the critical enterprise. He needs to establish the objective validity of the
categories; he does not need to spell out the subjective details of the faculty
of thought. Kant is trying to show that the categories underlie our
judgments about objects. Judgments, however, are the products of the threestage
model of mental activity outlined in the subjective deduction, and the
categories enter the model only in the third stage. The first two stages are
thus inessential to the argument. The subjective deduction, moreover, treats
the crucial third stage cursorily, leaving the role of the categories unclear. So,
Kant begins another argument, the objective deduction, to treat only the
relation between judgments and the categories. In the second edition, Kant
omits the subjective deduction entirely and elaborates the objective
deduction of the first edition.
Kant begins, not by considering the process of transforming the data of
sense into judgments, but by reflecting on the form of sensibility itself.
“We must begin with pure apperception,” he says. “Intuitions are nothing
to us, and do not in the least concern us if they cannot be taken up into
consciousness” (A 116). That is, the model of mental activity presented in
the subjective deduction presupposes, even at its earliest stage, the unity of
consciousness. It relates the data of sense to a single consciousness or mind
in which reside the faculties of sensibility, imagination, and understanding.
For the manifold representations, which are given in an intuition,
would not be one and all my representations, if they did not all
belong to one self-consciousness. As my representations (even if I am
not conscious of them as such) they must conform to the condition
under which alone they can stand together in one universal selfconsciousness,
because otherwise they would not all without
exception belong to me.
(B 132–3)
The unity of consciousness thus underlies the possibility of sensation and
thought. Kant obtains “the transcendental principle of the unity of all that
is manifold in our representations, and consequently also in intuition” (A
116), which he terms “the highest principle in the whole sphere of human
knowledge” (B 135). All representations are representations precisely
because they can be represented in empirical consciousness. But an
empirical consciousness requires a transcendental consciousness, for it is
unified without containing its unity as an element. All representations
therefore presuppose the transcendental unity of apperception.
To put Kant’s argument differently: Empirical consciousness, as far as
its contents are concerned, is a mixed bag. We cannot discover its unity
from its contents. Nor can we determine that a given succession of mental
states is unified into a single empirical consciousness by examining the
contents of those states: “the combination (conjunctio) of a manifold in
general can never come to us through the senses, and cannot, therefore, be
already contained in the pure form of sensible intuition” (B 129). That a
given representation is Jones’s representation, therefore, we cannot
analyze by appeal to monadic properties of that representation. We cannot
analyze it by appeal to relations among representations. We must instead
analyze it by appeal to a relation between the representation and
something else. Whatever is responsible for the unity of consciousness is
not to be found in empirical consciousness but in the relation between its
contents and something else, outside and underlying empirical
consciousness. That is the transcendental unity, “that which itself contains
the ground of the unity of diverse concepts in judgment, and therefore of
the possibility of the understanding, even as regards its logical
employment” (B 131). At one point Kant even identifies the
transcendental unity with the understanding (B 134 n.). The
transcendental unity of apperception manifests itself in the ‘I think’ that
we can append to all our judgments and representations:
It must be possible for the ‘I think’ to accompany all my
representations; for otherwise something would be represented in me
which could not be thought at all, and that is equivalent to saying
that the representation would be impossible, or at least would be
nothing to me.
(B 132)
This argument for the transcendental unity of consciousness allows Kant
to speak of a transcendental principle: “a principle of the synthetic unity
of the manifold in all possible intuition” (A 117). The principle of the
unity of consciousness itself is analytic, roughly of the form ‘I am I’ (B
135). But the transcendental principle Kant obtains from it is nonetheless
synthetic. We have seen that a sensation is part of Jones’s empirical
consciousness if and only if it stands in the appropriate relation to Jones’s
transcendental unity of apperception. This, Kant insists, is a necessary
truth about our kind of consciousness, one which permits a priori
knowledge of the unity of consciousness without manifesting that unity
explicitly in its contents. It follows that Jones can receive a sensation only
if it stands in relation to Jones’s transcendental unity. We can know a
priori, then, that any sensation must relate to the transcendental unity:
“all the manifold of intuition should be subject to conditions of the
original synthetic unity of apperception” (B 136). This proposition,
furthermore, is synthetic. We derive it, not by analyzing the concept of
sensation or even the concept of the transcendental unity, but by
connecting the two by way of the transcendental argument just reviewed.
As we might expect concerning the argument for any synthetic truth, it
rests on experience. But it permits a priori knowledge, knowledge that can
be derived independently of experience and that holds necessarily, because
it concerns the form of any possible experience.
Kant is driving toward the conclusion that “appearances have a
necessary relation to the understanding” (A 119). Appearances, he says,
are “data for a possible experience”; they therefore have to relate to the
understanding. The transcendental unity of apperception is responsible for
what Kant calls the affinity of our representation—that is, their being our
representations, their constituting a single empirical consciousness—and
also the rule-governed character of the synthesis of the manifold of
intuition. If that synthesis were not rule-governed, the combination of the
data of sense would not yield knowledge but random and “accidental
collocations” (A 121) such as the products of imagination in the usual
sense. We may freely combine concepts, to form the notion of a threeheaded
dragon or a golden mountain, but we gain no knowledge of what
is actual from exercising that freedom. We attain knowledge of objects
because the construction of objects actually presented in experience is rulegoverned.
Sensibility presents us with the data of experience, giving it the form of
space and time; the understanding formulates judgments. The rulegoverned
synthesis linking the two is a product of the imagination and is
unified by pure apperception. Our perception of a triangle, for example, is
rule-governed; we cannot connect any sensations we like, label them a
triangle, and obtain knowledge. The rule, in this case, is quite specific
about geometrical form. Underlying such specific rules, Kant points out, is
a general set of rules for generating concepts of objects. We can call
something a triangle only if it has three sides and three angles. More
broadly, we can call something an object only if it meets certain
conditions, that is, satisfies certain rules. Those rules are specified by the
categories. Kant therefore characterizes the understanding as the faculty of
rules.
The objective deduction, Kant maintains, shows that we can know
objects because we construct them: “Thus the order and regularity in the
appearances, which we entitle nature, we ourselves introduce. We could
never find them in appearances, had not we ourselves, or the nature of our
mind, originally set them there” (A 125). The understanding,
consequently, is nothing less than “the lawgiver of nature” (A 126). This
follows from Kant’s argument, for it has shown that the transcendental
unity is “an objective condition of all knowledge. It is not merely a condition
that I myself require in knowing an object, but is a condition under which
every intuition must stand in order to become an object for me” (B 138).
THE DIALECTIC
The Transcendental Analytic and related portions of the Critique attempt
to justify Kant’s rationalism. The Transcendental Dialectic, which
comprises most of the second half of the book, tries to justify Kant’s thesis
of immanence. As Kant puts it, the topic of the Dialectic is illusion.
Certainly, he means to show that the hope of extending knowledge beyond
the realm of sense experience is illusory. But he uses the term ‘illusion’ in a
more specific sense: “an illusion may be said to consist in treating the
subjective condition of thinking as being knowledge of the object” (A 396;
see A 297, B 353–4). The key to the Analytic is the Copernican revolution,
the idea that the faculty of thinking constitutes objects. This should not
tempt us to conclude, however, that subjectivity and objectivity—thinking
and knowing—match effortlessly. Clearly we may think of things that are
not objectively real through imagination. We may also make mistakes.
Most seriously, our thinking extends easily beyond the realm of sense
experience. We may engage in metaphysical contemplation, arguing about
the freedom of the will, the existence of God, and the mortality or
immortality of the soul. But Kant denies that we can attain any real
knowledge of these matters.
Kant differentiates thinking and knowing, subjectivity and objectivity,
by distinguishing the transcendental unity of apperception from the
subjective unity of consciousness. To understand the distinction, we must
return to the argument of the Transcendental Deduction, which uses the
subjective unity to argue for the transcendental unity. The subjective unity
of consciousness is a determination of inner sense. The manifold of
intuition is given to us in experience, and our experience constitutes a
single experience; this is the subjective unity. The manifold of intuition is
united in the concept of an object through the transcendental unity. The
subjective unity of consciousness is a condition of all thinking; the
transcendental unity is a condition of all knowing.
This distinction is extremely important for Kant; transcendent
metaphysics results from its confusion. We may think whatever we like in
imagination. We may connect concepts and intuitions freely without
concern for their presence in experience. The transcendental unity,
however, directs our thought toward an object and toward reality. We can
know a synthetic judgment only by some connection with experience. This
is why we cannot have knowledge that transcends experience: “The
possibility of experience is, then, what gives objective reality to all our a
priori modes of knowledge” (A 156, B 195). Indeed, it explains Kant’s first
example of a synthetic a priori principle: “every object stands under the
necessary conditions of synthetic unity of the manifold of intuition in a
possible experience” (A 158, B 197).
Kant’s distinction between the transcendental and subjective unities has
two important consequences. First, a rational psychology—a discipline
taking the ‘I think’ as its sole text (A 343, B 401) and amounting to a
theory of the soul—is impossible. One might suppose, given the account of
the transcendental unity, that the “I,” or, to use Kant’s term, the soul, is a
simple, unified substance, and that we can discover this a priori. This,
however, is a confusion. One can argue that the representation of the “I”
is a representation of a substance, of something simple and unified. But to
deduce that the “I” is a substance, simple and unified, is to commit a
fallacy.10 In fact, it is to invite the skeptic’s objections all over again.
Nothing here guarantees the veridicality of our representations. From the
perspective of transcendental (rather than rational, that is, rationalist and
transcendent) psychology, the “I” is “completely empty”: “it is a bare
consciousness which accompanies all concepts. Through this I or he or it
(the thing) which thinks, nothing further is represented than a
transcendental subject of the thoughts=X” (A 346, B 404).
As with the self, so with things-in-themselves. The second consequence
of Kant’s distinction is thus that knowledge of things-in-them-selves is
impossible; knowledge is limited to the sphere of experience. The limits of
knowledge become clear in thinking about the role of the categories. The
pure concepts of the understanding are conditions of the possibility of
experience. They have a priori validity, against the claims of the skeptic,
because “all empirical knowledge of objects would necessarily conform to
such concepts, because only as thus presupposing them is anything
possible as an object of experience” (A 93, B 126). Objects of experience
must conform to the categories. Objects beyond the realm of experience,
however, face no such constraint. In fact, we have no reason to believe
that the categories apply to them at all. The categories conform to objects
of possible experience because we synthesize those objects from the data
of sensibility. What lies beyond sensibility lies beyond the categories, for
we have no reason to believe that it results from such a process of
synthesis.
This means that transcendent metaphysics is impossible. Metaphysical
knowledge, to be interesting, must be knowledge of the world; it cannot be
merely verbal. So, it must consist of synthetic propositions. Moreover, it
cannot rely on experience; to be necessary and nonempirical, it must be a
priori. Kant, as a rationalist, is committed to the possibility of synthetic a
priori knowledge. But such knowledge is possible only transcendentally,
that is, through the contemplation of what makes experience possible. We
secure the possibility of synthetic a priori knowledge by arguing for the
categories. They apply, however, only to objects of possible experience.
Kant derives rationalism, therefore, only by undercutting transcendence.
No other objects, besides those of the senses, can, as a matter of fact,
be given to us, and nowhere save in the context of a possible
experience; and consequently nothing is an object for us, unless it
presupposes the sum of all empirical reality as the condition of its
possibility.
(A 582, B 610)
We can witness Kant’s application of his principle of immanence in his
refutation of the cosmological argument for the existence of God. That
argument appears in Aquinas, for example, as follows:
In the observable world causes are to be found ordered in series; we
never observe, or even could observe, something causing itself, for
this would mean that it preceded itself, and this is impossible. Such a
series of causes, however, must stop somewhere. For in all series of
causes, an earlier member causes an intermediate, and the
intermediate a last (whether the intermediate be one or many). If you
eliminate a cause, you also eliminate its effects. Therefore, there can
be neither a last nor an intermediate cause unless there is a first. But
if the series of causes goes on to infinity, and there is no first cause,
there would be neither intermediate causes nor a final effect, which is
patently false. It is therefore necessary to posit a first cause, which all
call “God.”11
Kant’s transcendental critique of this argument alleges “a whole nest of
dialectical assumptions,” of which he points out several: (a) The argument
assumes that each event in the observable world has a cause. Kant agrees;
he regards it as a synthetic a priori truth. But, as such, “This principle is
applicable only in the sensible world; outside that world it has no meaning
whatsoever” (A 609, B 637). (b) Why can’t a series of causes go on to
infinity? Kant finds nothing to justify this assumption even in the sensible
world, (c) Is it true that, if you eliminate a cause, you eliminate its effects?
Even if this holds in experience, we have no justification for extending it
beyond experience, (d) Finally, why should we identify the first cause as
God? Philosophers have understood God as the perfect being, “that, the
greater than which cannot be conceived,” the being more real than any
other, and the necessarily existent being. To conclude that the first cause is
God, we must show at least that the first cause is perfect and necessary.
Nothing in the proof accomplishes this. Consequently, Kant maintains
that “the so-called cosmological proof really owes any cogency which it
may have to the ontological proof from mere concepts” (A 607, B 635),
for it assumes that perfection, necessity, and being the first cause all hold
of the same thing.
The ontological proof appears in Anselm in the following form:
Certainly, this being exists so truly that one cannot even think that it
does not exist. For whatever must be thought to exist is greater than
whatever can be thought not to exist. Hence, if that greatest
conceivable being can be thought not to exist, then it is not the
greatest conceivable being, which is absurd. Therefore, something so
great that a greater cannot be conceived exists so truly that it cannot
even be thought not to exist.12
The argument means to show that perfection entails necessity. That God is
perfect Anselm takes as an analytic truth, as following from a definition of
‘God.’ He concludes that God exists necessarily.
Kant’s assault on this argument is more complicated than his attack on
the cosmological proof, but also more illuminating. This proof is a
paradigm example of illusion, the mistaking of the subjective for the
objective. It tries to establish the necessary existence of God from the mere
concept of God. Kant is willing to grant that the argument shows that the
concept of God, so defined, includes the concept of existence. But he
denies that this implies anything at all about the existence of God in
reality.
The key to Kant’s attack on the ontological argument is his
contention that ‘being’ is not a real predicate. Kant defines a
determining predicate as “a predicate which is added to the concept of
the subject and enlarges it” (A 598, B 626). It follows that a judgment
with a determining predicate must be synthetic, for the predicate must
enlarge the subject; it cannot already be contained in it. “‘Being’,”
Kant insists, “is obviously not a real predicate; that is, it is not a
concept of something which could be added to the concept of a thing”
(A 598, B 626). A real predicate is capable of serving as a determining
predicate. ‘Being,’ evidently, is not.
We might be tempted to conclude that existential judgments such as
‘God is’ or ‘God exists’ are analytic, for ‘being’ cannot serve as a
determining predicate. But Kant clearly maintains that all existential
judgments are synthetic. He argues specifically that ‘God exists’ is not
analytic, and concludes, “as every reasonable person must, that all
existential propositions are synthetic” (A 598, B 626). It follows that
‘being’ cannot be contained in the concept of a thing. But how can
existential judgments be synthetic if they lack determining predicates?13
A synthetic judgment is not merely verbal; its predicate, according to
Kant, must add something not already included in its subject. ‘Being,’
then, must add something to every subject concept. Yet it is not
determining; it does not add to and enlarge the subject concept. ‘Being’
adds something that does not enlarge the concept of the subject.
To understand how this is possible, we must return to Kant’s theory
of concepts. Concepts are functions of synthesis that organize and
unify the material of sense. They mold the data of sense into
perceptions of objects (A 68, B 93, B 95). Consequently, their content
relates essentially to the manifold of sense. In language and in thought,
we can manipulate items however we like. Only through links to
intuition, actual or possible, can we move from thinking to knowledge,
activating the transcendental unity and giving our thoughts objective
validity. (See A 155, B 194–5, B 146, B 165–6.) In short, concepts have
content by virtue of the patterns of possible intuitions falling under
them. This entails that ‘being’ is not a real predicate, for it lacks this
sort of content. It cannot enlarge a subject concept; any intuition
falling under the concept of a dollar falls under the concept of an
existing dollar, and vice versa (A 599–600, B 627–8). It follows,
moreover, that existential judgments are synthetic, for existence cannot
be part of the content of a subject concept (A 225, B 272).
If ‘being’ lacks content definable in terms of the manifold of sense, what
does it contribute to a judgment? Existential judgments do not enlarge or
alter a rule for the synthesis of the manifold of intuition, but express the
relation of the rule to the understanding. For Kant, then, ‘being’ is
relational. The same holds of possibility and necessity, which share the
fourth, “Modality” portion of the table of categories.14 Kant maintains
that the modality of a judgment adds nothing to the judgment’s content.
Instead, it determines the judgment’s relation to the understanding: “The
principles of modality thus predicate of a concept nothing but the action
of the faculty of knowledge through which it is generated” (A 234, B 286–
7). Existence and the other modalities contribute “a relation to my
understanding” (A 231, B 284), determining “only how the object,
together with all its determinations, is related to understanding and its
empirical employment, to empirical judgment, and to reason in its
application to experience” (A 219, B 266).
Kant compares the ‘being’ at stake in existential judgments to the
‘being’ of the copula (A 74, B 100; A 598–9, B 626–7). Both “distinguish
the objective unity of given representations from the subjective” (B 141–
2). Only by relating the terms of a judgment to the transcendental unity of
apperception
does there arise from this relation a judgment, that is, a relation
which is objectively valid, and so can be adequately distinguished
from a relation of the same representations that would have only
subjective validity—as when they are connected according to the
laws of association.
(B 142)
‘Being’ in both roles distinguishes the subjective from the objective.
This is why the ontological proof is Kant’s paradigm case of dialectical
illusion. The advocate of the proof mistakes the subjective for the
objective, failing to recognize that God’s existence or necessity cannot be
established analytically, from the definition of ‘God’ alone. In saying that
something exists, we assert a relation to the understanding; we assert that
we may experience the object, or stand in relation to it by way of
empirical laws (A 219, B 266–7; A. 234 n., B 287 n.; A 616, B 644). And
this cannot be derived from concepts alone. It follows that nothing exists
with analytic or logical necessity:
If I take the concept of anything, no matter what, I find the existence
of this thing can never be represented by me as absolutely necessary,
and that, whatever it may be that exists, nothing prevents me from
thinking its nonexistence.
(A 615, B 643)
We can now see how Kant can practice the transcendental method while
rejecting transcendent metaphysics. The latter confuses the subjective and
the objective, failing to recognize that concepts have content only in
relation to experience. The transcendental method, however, focuses
directly on the relation to the understanding at stake in questions of
modality. Kant deduces the categories by reflecting on the sort of relation
that must hold if experience of objects is to be possible.
HUMANISM
Kant carefully distinguishes his view from the idealism of Berkeley, which
assails the notion of a reality beyond the realm of ideas. Kant’s solution to
Platonism’s problems relies on distinguishing phenomena from noumena.
Kant thus insists on the need to recognize nonmental objects, things-inthemselves,
of which our appearances are appearances.
Kant nevertheless realizes that his theory is a form of idealism—
transcendental idealism, he calls it—for truth, objectivity, and existence,
within the theory, become fundamentally epistemic notions. The same
holds of all the modalities—possibility, truth or existence, and necessity —
for all have the same function of relating a judgment to the understanding.
Metaphysics is inseparable from epistemology; the root notions of
metaphysics are all, in the end, epistemological notions.
Kant’s epistemic conception of modality underlies his identification of a
priori and necessary judgments. Saul Kripke has attacked this identification,
pointing out that a prioricity is a matter of epistemology—can something be
known independently of experience?—while necessity is a matter of
metaphysics. Kripke has alleged, against Kant, that there can be contingent a
priori and necessary a posteriori truths.15 This seems plausible on the
metaphysical view of necessity that Leibniz and Kripke share, namely, that
necessity is truth in all possible worlds. But Kant rejects that view. A
judgment is a priori if it can be known independently of all experience; if, that
is, it holds no matter what experience might yield, or, to put it differently, if it
holds no matter what the world looks like. A judgment is necessary, on the
Leibniz-Kripke view, if it holds no matter what the world is like. Kant does
not confuse these notions; he rejects the latter precisely because it is
metaphysical in a transcendent sense. The truth of skepticism is that we
cannot know what the world is like. The only notion of modality we can use
is epistemic, in which we consider possible experiences rather than possible
worlds. On this conception, of course, the a priori and the necessary are not
only equivalent, but obviously so.
Moreover, it becomes possible to attain knowledge of necessary truths
about objects of experience. Reason gets itself into trouble when it tries to
leave the realm of possible experience. Kant is able to defend our
knowledge of necessary truths against skeptics such as Hume because, for
him, the a priori and necessary extend to the immanent sphere only, not to
the transcendent. They are limited to the realm of possible experience. If a
priori judgments were necessary in a strong metaphysical sense, then
Kant’s immanence thesis would be hard to understand.
The epistemic character of the basic notions of metaphysics—when
these notions and, correspondingly, metaphysics are properly construed—
is the central consequence of Kant’s Copernican revolution. It would
become fundamental to virtually all nineteenth-century approaches to
philosophy. Skepticism, perhaps the chief philosophical puzzle since
Descartes, would give way to puzzles arising from Kant’s uniquely
humanistic idealism. For Kant, as for the ancient Sophist Protagoras, man
is the measure of all things. Kant, of course, takes the definite article here
seriously. There is one and only one measure: the categories underlie all
possible experience. Not everyone would agree. The nature and especially
the uniqueness of the measure would define the chief battleground for
philosophers during the next two centuries.
NOTES
1 R.Rorty, Philosophy and the Mirror of Nature (Princeton: Princeton University
Press, 1979), p. 149; N.Kemp Smith, A Commentary to Kant’s Critique of Pure
Reason (Atlantic Highlands, NJ: Humanities Press, 1962), p. vii.
2 This and other citations from the Critique of Pure Reason are from the
translation of N.Kemp Smith (London: Macmillan, 1929; New York: St
Martin’s Press, 1965). Throughout, any emphasis in the quotations is Kant’s;
the pagination is that of the original first (A) and second (B) editions.
3 H.Vaihinger, Commentar zu Kant’s Kritik der Reinen Vernunft, Vol. I
(Stuttgart: Spemann, 1881), pp. 117–20.
4 The analysis is Vaihinger’s. See ibid., p. 50; Kemp Smith, op. cit., pp. 13–14.
5 Descartes, Meditations, III.
6 Kant often speaks of the content and form of judgments in just this way.
Introducing the table of judgments, he writes, “If we abstract from all content
of a judgment, and consider only the mere form of understanding,” we derive
the table (A 70, B 95). At other times, however, he treats the form and content
very differently. Modality, for example, differs from the other aspects of
judgment in the table in that “it contributes nothing to the content of a
judgment (for, besides quantity, quality, and relation, there is nothing that
constitutes the content of a judgment)” (A 74, B 100). These are plainly
inconsistent. In the former passage, Kant speaks of empirical content or, more
precisely, the content of the impure concepts in a judgment; in the latter, he
speaks of logical content. It is tempting to identify the form of a judgment
with its logical content, but Kant’s theory of the modalities makes that
impossible. See my “Kant on Existence and Modality,” Archiv für Geschichte
der Philosophie, 64, 3 (1982): 289–300.
7 That is, concepts of objects are rules of individuation as well as application.
For a sophisticated modern treatment of this distinction, see A.Gupta, The
Logic of Common Nouns (New Haven: Yale University Press, 1984).
8 See H.Vaihinger, “Die transcendentale Deduktion der Kategorien,”
Gedenkschrift für Rudolf Haym (1902); Kemp Smith, op. cit., pp. 202ff.
9 Kant’s theory of time occupies part of the Transcendental Aesthetic. In brief,
time is the form of inner sense, the progression of sensations, thoughts, and, in
general, representations that constitutes empirical consciousness. Space and
time, Kant argues, are a priori forms of intuition, for they are necessary
conditions of sensation. We cannot sense anything without sensing it in space
and time, that is, as spatially and temporally located. Time is moreover the
form of inner sense because we cannot think anything without thinking it in
time, that is, without our thought being part of a temporal sequence.
10 See W.Sellars, “Some Remarks on Kant’s Theory of Experience” and “…this I
or he or it (the thing) which thinks…,” in his Essays on Philosophy and its
History (Dordrecht: Reidel, 1974), pp. 44–61, 62–92.
11 St Thomas Aquinas, Summa Theologiae, la. 2; my translation.
12 St Anselm of Canterbury, Proslogion, III; my translation.
13 For more on this apparent contradiction, see J.Shaffer, “Existence,
Predication, and the Ontological Argument,” Mind, 71 (1962): 307–25;
W.H.Walsh, Kant’s Criticism of Metaphysics (Edinburgh: Edinburgh
University Press, 1975), p. 7; G.Vick, “Existence was a Predicate for Kant,”
Kant-Studien, 61 (1970): 357–71, esp. 363–4; R.Coburn, “Animadversions
on Plantinga’s Kant,” Ratio, 13 (1971): 19–29, esp. 21–2; R.Campbell, “Real
Predicates and ‘Exists’,” Mind, 83 (1974): 96ff.; and my “Kant on Existence
and Modality,” op. cit., pp. 291–5.
14 One of the few commentators to observe this is H.Heimsoeth, Transzendentale
Dialektik (Berlin: de Gruyter, 1969), Vol. III, p. 480.
15 See S.Kripke, Naming and Necessity (Cambridge, Mass.: Harvard University
Press, 1972, 1980), pp. 34–9.
SELECT BIBLIOGRAPHY
Original language editions
2.1 Kant, I. Critik der reinen Vernunft, Riga: J.F.Hartknoch, 1781.
2.2 Kants gesammelte Schriften, 29 vols, ed. Deutschen (formerly Königlich
Preussische) Akademie der Wissenschaften, Berlin: de Gruyter (and
predecessors), 1902–.
2.3 Kant, I. Werke, Academie Textausgahe: Anmerkungen der Bande I-IX,
Berlin: de Gruyter, 1977.
English translations
2.4 Kant, I. Critik of Pure Reason, trans. F.Haywood, London: W.Pickering, 1838.
2.5 Kant, I. Critique of Pure Reason, trans. J.M.D.Meiklejohn, New York:
Colonial Press, 1899; London: J.M.Dent, 1934, 1940.
2.6 Kant, I. Critique of Pure Reason, trans. N.Kemp Smith, London: Macmillan,
1929; New York: St Martin’s Press, 1965.
2.7 Kant, I. Critique of Pure Reason, trans. W.Schwarz, Aalen: Scientia, 1982.
Books on Kant (in English)
2.8 Beck, L.W. Early German Philosophy: Kant and his Predecessors,
Cambridge, Mass.: Belknap Press of Harvard University Press, 1969.
2.9 Beck, L.W. Essays on Kant and Hume, New Haven: Yale University
Press, 1978.
2.10 Beck, L.W. (ed.) Kant Studies Today, La Salle, Ill.: Open Court, 1969.
2.11 Beck, L.W. (ed.) Kant’s Theory of Knowledge, Dordrecht: Reidel, 1974.
2.12 Broad, C.D. Kant: An Introduction, Cambridge: Cambridge University Press,
1978.
2.13 Cassirer, E. Kant’s Life and Thought, trans. J.Haden, New Haven and
London: Yale University Press, 1981.
2.14 den Ouden B.D., and Moen, M. (eds) New Essays on Kant, New York: Peter
Lang, 1987.
2.15 Guyer, P. (ed.) The Cambridge Companion to Kant, Cambridge: Cambridge
University Press, 1992.
2.16 Korner, S. Kant, Harmondsworth: Penguin, 1955.
2.17 Scruton, R. Kant, Oxford: Oxford University Press, 1982.
2.18 Walker, R.C.S. Kant, London: Routledge & Kegan Paul, 1978.
2.19 Werkmeister, W.H. Kant, the Archetectonic and Development of his
Philosophy, La Salle, 111.: Open Court, 1980.
2.20 Wolff, R.P. (ed.) Kant: A Collection of Critical Essays, Notre Dame:
University of Notre Dame Press, 1968.
2.21 Wood, A.W. (ed.) Self and Nature in Kant’s Philosophy, Ithaca: Cornell
University Press, 1984.
Books on the Critique of Pare Reason (in English)
2.22 Allison, H.E. Kant’s Transcendental Idealism: An Interpretation and
Defense, New Haven: Yale University Press, 1983.
2.23 Ameriks, K. Kant’s Theory of Mind, Oxford: Clarendon Press, 1982.
2.24 Aquila, R.E. Representational Mind: A Study of Kant’s Theory of
Knowledge, Bloomington: Indiana University Press, 1983.
2.25 Bennett, J. Kant’s Analytic, Cambridge: Cambridge University Press, 1966.
2.26 Bennett, J. Kant’s Dialectic, Cambridge: Cambridge University Press,
1974.
2.27 Brittan, G.G. Kant’s Theory of Science, Princeton: Princeton University
Press, 1978.
2.28 Ewing, A.C. A Short Commentary to Kant’s Critique of Pure Reason,
Chicago: University of Chicago Press, 1938.
2.29 Forster, E. (ed.) Kant’s Transcendental Deductions: The Three Critiques and
the Opus Postumum, Stanford: Stanford University Press, 1989.
2.30 Kemp Smith, N. A Commentary to Kant’s Critique of Pure Reason, Atlantic
Highlands, NJ: Humanities Press, 1962.
2.31 Paton, W.E. Kant’s Metaphysic of Experience, London: Allen & Unwin,
1970.
2.32 Prichard, H.A. Kant’s Theory of Knowledge, Oxford: Oxford University
Press, 1909.
2.33 Rescher, N. Kant’s Theory of Knowledge and Reality: A Group of Essays,
Washington: University Press of America, 1983.
2.34 Schaper, E., and Vossenkuhl, W. (eds) Reading Kant: New Perspectives on
Transcendental Arguments and Critical Philosophy, Oxford:
Blackwell, 1989.
2.35 Sellars, W. Science and Metaphysics: Variations on Kantian Themes, London:
Routledge & Kegan Paul, 1968.
2.36 Seung, T.K. Kant’s Transcendental Logic, New Haven: Yale University
Press, 1969.
2.37 Strawson, P.F. The Bounds of Sense: An Essay on Kant’s Critique of Pure
Reason, London: Methuen, 1966.
2.38 Walsh, W.H. Kant’s Criticism of Metaphysics, Edinburgh: Edinburgh
University Press, 1975.
2.39 Wilkerson, T.E. Kant’s Critique of Pure Reason, Oxford: Oxford University
Press, 1976.
2.40 Winterbourne, A. The Ideal and the Real: An Outline of Kant’s Theory
of Space, Time, and Mathematical Construction, Dordrecht:
Kluwer, 1988.
2.41 Wolff, R.P. Kant’s Theory of Mental Activity, Cambridge, Mass.: Harvard
University Press, 1963.
Routledge History of Philosophy.
Taylor & Francis e-Library.
2005.