Lecture on Kant I: The Copernican Revolution in Philosophy
Phil 212
I. Introduction
1. The young Kant, scientist and metaphysician.
2. What is “metaphysics” for Kant?
Two definitions:
1. “Metaphysics—a wholly isolated speculative cognition of reason that elevates itself entirely
above all instruction from experience, and that through mere concepts (not, like mathematics,
through the application of concepts to intuition)…” (Bxiv).
2. Later, however, Kant says that metaphysics is the science that “claims a priori insight (as it
pretends) into those laws confirmed by the commonest experience” (Bxiv). A “metaphysics of
experience.”
Very generally: metaphysics in 18th century thought is the purported a priori science of “first
principles” or the “most universal properties of things.” (cf. Beiser, p.27)
Christian Wolff (a Leibnizean and dominant intellectual figure in 18 th century Germany):
“Ontology, general cosmology and pneumatics are designated by the common name
‘metaphysics.’ Hence metaphysics is the science of being, of the world in general, and of spirits”
(Discursus praeliminaris de philosophia in genere (1728), section 79).
3. The sad state of metaphysics. Dogmatism-Skepticism-Commonsensism.
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One of the contending parties—the one by which Kant is most influenced—is rationalism:
Descartes, Spinoza, Malebranche, Leibniz, and Wolff. Insoluble controversies among these
thinkers ushers in skepticism (Hume) which makes ‘short work of all metaphysics” (Bxxxvi). We
are left with “a mere groping, and what is the worst, a groping among mere concepts” (Bxv).
Hume, says Kant, woke him from his “dogmatic slumbers” (4:260).
Unlike the common sense theorists, Kant thinks the resulting weariness and apathy is unstable.
First, it can’t be maintained. The natural disposition to metaphysics “would remain even if all
[other sciences] were swallowed up by an all-consuming barbarism” (Bxiv).
Furthermore, common sense philosophy often tends towards dogmatic positions regarding
ultimate principles: “These so-called indifferentists, to the extent that they think anything at all,
always unavoidably fall back into metaphysical assertions, which they yet profess so much to
despise” (Ax).
Why does all of this happen? In other words, “Why has nature afflicted our reason with the
restless striving for such a path [of science in metaphysics], as if it were one of reason’s most
important occupations?” (Bxv)
A “natural disposition to such a science” (4:280).
“Human reason is so keen on building that more than once it has previously erected a
tower, but has afterwards torn it down again in order to see how well constituted its
foundation may have been” (4:256).
“For that which necessarily drives us to go beyond the boundaries of experience
and all appearances is the unconditioned, which reason necessarily and with
every right demands in things in themselves for everything that is conditioned, thereby
demanding the series of conditions as something completed” (Bxx).
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This drive for knowledge of particular constituents of the unconditioned will be ruled out as
illegitimate by the critical philosophy, although Kant will explicitly leave room for “belief” or
“faith” (Glaube) about it, at least for practical purposes (4:278). But as it turns out, Kant himself
thinks we are in possession of some substantive a priori knowledge, not about supersensible
unconditioned things, but rather about the fundamental principles governing all our experience.
For Kant, such knowledge requires an explanation. In this explanation lies a way forward for at
least some kinds of metaphysics.
4. Pure Reason.
“Now reason is the faculty that provides the principles of knowledge a priori. Hence pure reason is that
which contains the principles for knowing something absolutely a priori … We can regard a science of the
mere estimation of pure reason, of its sources and boundaries, as … a critique of pure reason” (A10-11).
5. The CPR, and the Prolegomena to it, is a “treatise on method” (Bxxii), which will investigate whether
metaphysics can be led onto “the secure path of a science” (Bvii). So what makes for a successful science?
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Consider logic: “That from the earliest times logic has traveled this secure course [as opposed to
merely groping around] can be seen from the fact that since the time of Aristotle it has not had to
go a single step backwards” (Bviii).
Logic is limited however in that it is “the science that exhaustively presents and strictly proves
nothing but the formal rules of thinking” (Bix).
Logicians know what their boundaries are (Bviii-ix).
Logic “seems to all appearance to be finished and complete” (Bviii).
However “for the advantage that has made it so successful logic has solely its own limitation to
thank” (Bix). Logic abstracts from all objects of knowledge, and relies only on the purely formal
Principle of Contradiction. The Principle of Contradiction itself provides no source of
metaphysical cognition (as Hume showed) and the logical consistency of a metaphysical system is
insufficient for its truth (4:257-8).
Consider mathematics: Kant thinks it was born out of a “revolution” of thought:
*An isosceles triangle is not something that we “find” and then inductively discover its
properties. Rather, it is something that we construct through concepts, and then we know
a priori what those properties will be—i.e., what every isosceles triangle will be like.
* Kant thinks he can draw the conclusion: “in order to know something securely a priori
[the person doing mathematics] had to ascribe to the thing nothing except what followed
necessarily from what he himself had put into it in accordance with its concept” (Bxi-xii).
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Consider also natural philosophy: And in particular the Principle of Causation on which it is
based.
*Hume noted that this is not a principle that can be deduced analytically from some
“relation of ideas,” and that it cannot be grounded in “matters of fact,” since it is
supposed to be a necessary truth (4:257-58).
*Hume’s solution was skepticism plus an appeal to habit/custom.
*Kant thinks that we need to do better, but that it will require figuring out a way in which
the very general principle of causation can be known synthetic a priori.
*This will have to involve something analogous to the “revolution” in mathematics,
where by we actually put into the subject something which allows us to then know a
priori what it will be like.
6. The Copernican Revolution in metaphysics.
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Two parts: (1) “The object (as an object of the senses) conforms to the constitution of our
faculty of intuition” (Bxvii). (2) “The objects [of experience], or – what is the same – the
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experience in which alone they can be cognized (as given objects), conforms to [certain]
concepts” (ibid.). [these concepts = Kant’s ‘categories’]
Succinctly put: “We can cognize of things a priori only what we ourselves have put into
them” (Bxviii).
The benefits of the revolution
The costs: “our rational cognition a priori … reaches appearances only, leaving the THING
IN ITSELF (Ding an sich) as something actual for itself but uncognized by us” (Bxx).
*The revolution produces “a very strange result, and one that appears very
disadvantageous to the whole purpose with which the second part of metaphysics
concerns itself, namely that with this faculty we can never get beyond the boundaries of
possible experience, which is nevertheless precisely the most essential occupation of this
science” (Bxix). There can be no theoretical knowledge of God, soul, world as a whole.
No special metaphysics as traditionally conceived.
*But note: Kant doesn’t merely want to make room for a priori knowledge of experience.
Famous passage: “I have … found it necessary to deny knowledge [of things in
themselves!], in order to make room [not only for a priori knowledge of appearances,
but] for faith [about things in themselves].” (Bxxx) This is the so-called “primacy of
practical reason.” So the knowledge that traditional metaphysicians took themselves to
have about supersensibles is done away with, in order to leave room for a different kind
of propositional attitude, which Kant calls “belief” or “faith” (Glaube) (again, see 4:278)
II. Preamble
I. Kant clarifies: The difference between analytic and synthetic judgments
A. Analytic: A is b, where b in some sense “belongs to” or “is contained in” the concept of A.
1. Example: All bodies are extended.
2. Another example: All bachelors are male.
3. The principle here is the principle of non-contradiction.
B. Synthetic: A is b, where b “lies entirely outside the concept of A” while still standing in some sort of
connection with it.
1. Example: All bodies are heavy
2. Another example: All water is H20.
3. The principle here must be something more than the principle of non-contradiction.
C. Judgments of experience (i.e. a posteriori judgments) are all synthetic.
1. The experience is what provides for the “connection” between A and b.
2. These judgments, Kant thinks, are always “contingent” and the connection between the
concepts will not be strictly universal or necessary.
D. What about synthetic a priori judgments?
1. What provides for the connection between A and b?
2. Example: “Everything that happens has its cause.”
Here “everything that happens” = A, and “has its cause” = b
II. Kant argues: Synthetic a priori judgments are contained as principles in all theoretical sciences of
Reason.
A. Arithmetic judgments are all synthetic a priori (4:267ff)
1. Many have thought that they are analytic, but they were wrong.
2. Kant’s example: 7 + 5 = 12
a. In this proposition, “12” involves an amplification of the concept of “7 + 5”—
it is not contained in the latter concept.
b. What kind of argument can Kant provide for this?
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B. Many geometrical judgments are synthetic a priori (4:269)
1. “The straight line between two points is the shortest.”
2. The concept of the straight contains within itself “nothing about magnitude,” but rather
only quality. So “shortest” is something “entirely additional to it, and cannot be extracted
out of the concept of the straight line by any analysis. Help here must be gotten from
intuition” (B17; cf. 4:269).
C. Natural science contains some synthetic a priori judgments as principles (B17-18)
1. “In all alterations of the corporeal world the quantity of matter remains unaltered.”
2. For in the concept of matter I do not think persistence of quantity, but just extension in
space.
D. What about metaphysics?
1. It is clearly not just analysis—we want to amplify our cognitions.
2. “The world must have a first beginning,” for instance.
III. Kant presents: The general problem of pure reason
A. The problem: “How are synthetic judgments a priori possible?”
1. This assumes, of course, that they are not just possible but actual. And K thinks he has
shown this by appealing to math and physics.
2. Re metaphysics, K says it is not yet in the form of a science but is at least present as a
“natural predisposition” and “need.”
B. Re metaphysics, then, all we can ask at the moment is “How is this natural predisposition
possible?”
1. The problem with this is that left to its own devices, the natural predisposition always
leads us into contradictions, which are a sure sign of error.
2. The key to getting it into shape as a science, then, is to “bring it to certainty regarding
either the knowledge or ignorance of objects, i.e., to come to a decision either about the
objects of its questions or about the capacity and incapacity of reason for judging
something about them, thus either reliably to extend our pure reason or else to set
determinate and secure limits for it” (B22).
3. This leads to the key question: “How is metaphysics possible as a science?”
IV. The idea and division of a special science under the name of a critique of pure reason
A. Now the “critique of pure reason” is specified as the science in question, namely that of discerning
whether and how metaphysics is possible. A critique that is both of and by pure reason.
B. Critique: “A science of the mere estimation of pure reason, of its sources and boundaries” (B25).
C. Another important definition: “I call cognition transcendental that is occupied not so much with objects
but rather with our mode of cognition of objects insofar as this is to be possible a priori.” (B25). Nothing
empirical is allowed.
D. Transcendental philosophy could contain more than a critique: it could be a system of all the synthetic a
priori principles of pure reason. Kant tries to go beyond mere critique in his later works.
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