Julius Sensat / Philosophy 453: Kant / Fall 2004 / Notes / Installment 6: Refutation of idealism; Phenomena and noumena

The following notes deal exclusively with the Refutation of Idealism, though I hope we will discuss the chapter on noumena and phenomena. I think that Gardner, pp. 198-206, provides a helpful entry into the relevant issues. For our purposes, the second edition version of the chapter (B294-315, pp. 354-365 in our text) is more important to get clear about (I also think it is easier to understand).

The Refutation of Idealism

This short section (pp. 326-329) was added in the second edition. It is supposed to contribute to Kant's campaign against "material" or "empirical" (A 369) idealism. In contrast with Kant's own idealism, transcendental idealism, material idealism claims that the "matter" of appearance, that which corresponds to sensation, derives from the subject; for this reason, these idealisms are forms of skepticism about the existence of an external, physical world. Kant was shocked that reviewers of the first edition assimilated his view to this one. In the preface to the second edition he remarks that it

remains a scandal of philosophy and universal human reason that the existence of things outside us (from which we after all get the whole matter for our cognitions, even for our inner sense) should have to be assumed merely on faith, and that if it occurs to anyone to doubt it, we should be unable to answer him with a satisfatory proof [Bxxxix n].

Kant takes material idealism to come in two forms:

Berkeley's "dogmatic" idealism, which Kant takes to imply that the world of physical objects is illusory or imaginary.
Descartes's "skeptical" or "problematic" idealism, which treats the existence of physical objects as less certain than the fact of one's own existence as a thinking being, to which each person has privileged access and which each person can ascertain with certainty simply by reflection on his own act of thinking.

As Gardner points out (pp. 180-181), Kant groups these two doctrines together as material or empirical idealism for two reasons:

Both assume that the immediate and primary objects of knowledge are subjective, private, mental entities rather than empirically real objects, and therefore they treat knowledge of physical objects as resting on inference from knowledge of inner states.
For this reason, neither can defend commonsense belief in empirical reality (regardless of their intentions).

Against both these views, Kant wants to reverse the traditional epistemic order and establish that our empirical knowledge of ourselves is itself dependent on our knowledge of physical objects. Kant seems to direct the Refutation against problematic idealism alone, since he delares in a prefatory comment (B274) that Berkeley's idealism has already been undercut by the arguments of the Aesthetic.

Kant presents the Refutation in the form of a proof of the following "theorem":

The mere, but empirically determined, consciousness of my own existence proves the existence of objects in space outside me [B275].

The proof is contained in the following paragraph:

I am conscious of my existence as determined in time. All time-determination presupposes something persistent in perception. This persistent thing, however, cannot be something in me, since my own existence in time can first be determined only through this persistent thing. Thus the perception of this persistent thing is possible only through a thing outside me and not through the mere representation of a thing outside me. Consequently, the determination of my existence in time is possible only by means of the existence of actual things that I perceive outside myself. Now consciousness in time is necessarily combined with the consciousness of the possibility of this time-determination: Therefore it is also necessarily combined with the existence of the things outside me, as the condition of time-determination; i.e., the consciousness of my own existence is at the same time an immediate consciousness of the existence of other things, outside me [B 275-276].

In the preface to the second edition (Bxxxix), Kant says that the third sentence should be replaced with the following one:

But this persisting element cannot be an intuition in me. For all the determining grounds of my existence that can be encountered in me are representations, and as such they themselves need something persisting distinct from them, in relation to which their change, and thus my existence in the time in which they change, can be determined.

In what follows I make the substitution and then break down the argument into five steps (my analysis is roughly similar to Allison's).

1. I am conscious of my existence as determined in time.

This is an assumption of empirical self-consciousness or inner experience which, Kant says, is "undoubted by Descartes" [B275]. The assumption is that I am conscious of my own representations as "phenomenal" or "subjective" objects succeeding one another in an objective time order. Kant hopes to show that this starting point has as a necessary presupposition knowledge of outer objects.

2. All time-determination presupposes something persistentin perception.

This premise is based on the First Analogy (concerning substance as persisting). Kant argues there that since time itself cannot be perceived, there must be something in perception that endures, in order for the representation of objects to be in a unitary time.

3. But this persisting element cannot be an intuition in me. For all the determining grounds of my existence that can be encountered in me are representations, and as such they themselves need something persisting distinct from them, in relation to which their change, and thus my existence in the time in which they change, can be determined.

This is the passage that replaces the third statement in the original statement of the argument. Kant is using "intuition" here in the sense of "intuited object." Kant apparently made the substitution in order to make clear that the Cartesian res cogitans (thinking being) could not serve as the required persisting element. Kant of course has stated, in his doctrine of apperception, that it is possible for us to be aware of our spontaneity as thinking subjects, but for him that is of no consequence because this awareness is a mere thought and not an intuition, so it cannot serve to determine an empirical consciousness of ourselves and the succession of our mental states in time (on this, see B 277-278). The second part of the passage makes clear that for Kant, our inner experience is that of a succession of representations. There is no purely inner empirical awareness or intuition of an enduring self.

4. Thus the perception of this persistent thing is possible only through a thing outside me and not through the mere representation of a thing outside me. Consequently, the determination of my existence in time is possible only by means of the existence of actual things that I perceive outside myself.

This step concludes that I could arrive at a warranted determination of my existence in time, that is, an account of the specific temporal relations holding among my representations, only if there are actually existing things outside me that could provide the necessary persisting backdrop. Now the first premise does not assert that I have such a warranted determination. I think we should read it as saying that I have inner experience of myself as in time (I have empirical inner perception of an objective succession of my representations). That is, we cannot yet use step 4 to assert the actual existence of objects outside ourselves. To do so, we have to link the objective awareness of succession to the possibility of arriving at a full temporal determination. This is just what Kant does in the next step.

5. Now consciousness [of my existence] in time is necessarily combined with the consciousness of the possibility of this time-determination: Therefore it is also necessarily combined with the existence of the things outside me, as the condition of time-determination; i.e., the consciousness of my own existence is at the same time an immediate consciousness of the existence of other things, outside me.

In the note beginning on Bxxxix, where Kant proposes the substitution in step 3, Kant puts forward a possible objection to step 4 as a non sequitur:

Against this proof one will perhaps say: I am immediately conscious to myself only of what is in me, i.e. of my representation of external things; consequently it still remains undecided whether there is something outside me corresponding to it or not.

However, Kant does not think the objection is valid, because the argument turns "the game that idealism plays" against it (B276). This "game" that the idealist plays is to use the indubitability of inner experience as a model of perfect certainty in order to cast doubt on the reality of outer experience. Kant claims that his argument shows that inner experience presupposes, in a very intimate way, the reality of outer experience. Thus, the dubitability of outer experience would cast doubt on inner experience.

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