INTRODUCTION [to the second edition]

I. Although all thinking starts with experience, not all of it arises from experience (p. 764).

A. This is because our thinking may be composite and contain:

1. A component contributed by experience.

2. And a component contributed by thinking itself.

3. These may be very difficult to separate.

B. Another way of putting (A.1) and (A.2) is to say that the source of (A.1) is a posteriori and (A.2) are a priori cognitions.

1. By 'a priori cognitions' Kant will mean pure a priori cognitions, i.e., those in which there is no empirical content.

II. Kant seeks a mark of a priori cognitions (p. 764).

A. Note that experience teaches us things, but cannot teach us that things are necessary.

1. So, when we think things are necessarily true, we make an a priori judgment.

B. Note that experience teaches us things, but cannot teach us that things are universal.

1. So, when we think things are universally true, we make an a priori judgment.

C. Hence, necessity and universality are indicators of the a priori.

D. Kant insists that there actually are such judgments.

1. Mathematics

2. Cause (contra what Hume says).

3. The certainty that comes from having experience itself: "For where might even experience get its certainty if all the rules by which it proceeds were always in turn empirical and hence contingent, so they could hardly be considered first principles?" (p. 765).

III. Philosophy needs a method to uncover a priori cognitions.

A. This project is especially pressing because, if we are to go beyond experience, it must be through a priori cognitions.

1. So, the topics of God, Freedom and Morality (to name just three) can only be resolved by this kind of inquiry.

IV. There are two ways for a subject to be related to a predicate (p. 767).

A. The predicate may be covertly contained in the subject (or concept of the subject).

1. E.g., all bodies are extended.

B. Or the predicate may be connected to the subject (or concept of the subject) but lie outside of it.

1. E.g., all bodies are heavy.

C. Kant will call (A) an analytic judgment (or "eluciditory") and call (B) a synthetic judgment (or "expansive").

D. Experiential judgments are synthetic. (What Hume calls "Matters of Fact").

E. Synthetic a priori judgments do not use experience, so their expansiveness must come from somewhere.

1. E.g., everything that happens has a cause is a judgment that goes beyond cause, but it cannot go beyond cause by relying on experience.

V. There are synthetic a priori judgments (p. 768).

Here is a famous matrix that you have to memorize in order to be a Learned Philosopher:

A. Mathematical judgments are synthetic a priori.

1. First note that mathematical judgments are a priori.

2. It might then be thought that they are analytic, but they are not. This is because when I think:

a. 7+5=, I have not already thought the concept '12'.

i. We must go beyond the concept to our intuition (by counting on our fingers or employing dots).

b. A straight line between any two points, I have not already thought the concept 'shortest'.

i. 'Straight' does not contain anything about magnitude.

B. Science contains judgments that are synthetic a priori.

1. In changes in the corporeal world, the quantity of matter stays the same.

2. Some laws of physics.

C. Metaphysics contains judgments that are synthetic a priori.

1. The goal of metaphysics is to expand our a priori cognition, so it must be synthetic.

VI. The general problem of pure reason is, how can any judgments be synthetic a priori (p. 769)?

A. A specific version of this problem is, how is pure mathematics possible?

B. Another is, how is pure natural science possible?

C. We also face, how does metaphysical reasoning work?

1. Any answer to this question should tell us how metaphysical reasoning can answer the questions it poses.

D. And, how is metaphysics possible?

VII. Thus we have the project of The Critique of Pure Reason (p. 771).

A. The goal is to arrive at the sum of the principles by which synthetic a priori judgments can be brought about.

1. This would allow a system of pure reason.

a. But it would not be a system of pure reason. Therefore, Kant here offers a propaedeutic to the system of pure reason.

i. It is thus not a doctrine, but a critique.

B. By 'transcendental', Kant means all thinking that deals with objects a priori.

C. A system of such concepts (of thinking) would be 'transcendental philosophy'.