Refutation Of Idealism

Material idealism is the theory which declares the existence of objects in space without us to be either:

1. Doubtful and indemonstrable, or

This is the problematical idealism of Descartes who admits the undoubted certainty of only one empirical assertion (assertio), to wit, “I am.”

2. False and impossible

This is the dogmatical idealism of Berkeley. He believes that space, together with all the objects in it, is an impossible thing.

Consequently, objects in space are mere products of the imagination.

This happens if space is thought of as a property of things in themselves. In this case, space is a condition, a nonentity.

My transcendental aesthetic has already destroyed this dogmatical idealism.

Problematical idealism makes no such assertion. But it only alleges our incapacity to prove the existence of anything besides ourselves through immediate experience is a rational theory.

The desired proof must therefore demonstrate that we have experience of external things, and not mere fancies.

Our internal experience is the same as the indubitable experience of Descartes.

• These are only possible under the previous assumption of external experience.

THEOREM: My sense-based consciousness of my own existence proves the existence of external objects in space.

PROOF

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

All determination in regard to time presupposes the existence of something permanent in perception.

This permanent something cannot be something in me because my existence in time is itself determined by this permanent something.

It follows that the perception of this permanent existence is possible only through a thing outside of me and not through the mere representation of a thing outside of me.

Consequently, the determination of my existence in time is possible only through the existence of real things external to me.

Consciousness in time is necessarily connected with the consciousness of the possibility of this determination in time.

It follows that consciousness in time is necessarily connected also with the existence of things outside of me, inasmuch as the existence of these things is the condition of determination in time.

The consciousness of my own existence is at the same time an immediate consciousness of the existence of other things outside of me.

Remark I. In the foregoing proof, the game which idealism plays is retorted on itself, and with more justice.

It assumed that the only immediate experience is internal and that from this we can only infer the existence of external things.

But, as always happens, when we reason from given effects to determined causes, idealism has reasoned with too much haste and uncertainty, for it is quite possible that the cause of our representations may lie in ourselves, and that we ascribe it falsely to external things.

But our proof shows that external experience is properly immediate,* that only by virtue of it—not, indeed, the consciousness of our own existence, but certainly the determination of our existence in time, that is, internal experience—is possible.

The representation “I am” is the expression of the consciousness which can accompany all my thoughts, is that which immediately includes the existence of a subject.

But in this representation we cannot find any knowledge of the subject. Therefore, also no empirical knowledge, that is, experience.

Experience contains passive-knowing in addition to the thought of something existing.

In this case, it is internal passive-knowing. It means that time, in relation to which the subject must be determined.

But the existence of external things is absolutely needed for this purpose.

It follows that internal experience is itself possible only mediately and through external experience.

The immediate consciousness of the existence of external things is proved by the possibility of this consciousness understood by us or not.

“Have we an internal sense, but no external sense, and is our belief in external perception a mere delusion?”

In order to fancy to ourselves anything as external, that is, to present it to the sense in intuition we must already possess an external sense, and must thereby distinguish immediately the mere receptivity of an external intuition from the spontaneity which characterizes every act of imagination.

For merely to imagine also an external sense, would annihilate the faculty of intuition itself which is to be determined by the imagination.

Remark II. Now with this view all empirical use of our faculty of cognition in the determination of time is in perfect accordance.

Its truth is supported by the fact that it is possible to perceive a determination of time only by means of a change in external relations (motion) to the permanent in space (for example, we become aware of the sun’s motion by observing the changes of his relation to the objects of this earth).

We possess nothing permanent that can correspond and be submitted to the conception of a substance as intuition, except matter.

This idea of permanence is not itself derived from external experience. It is a within-the-mind necessary condition of all determination of time, consequently also of the internal sense in reference to our own existence, and that through the existence of external things.

In the representation “I”, the consciousness of myself is not an intuition, but a merely intellectual representation produced by the spontaneous activity of a thinking subject.

It follows, that this “I” has not any predicate of intuition, which, in its character of permanence, could serve as correlate to the determination of time in the internal sense—in the same way as impenetrability is the correlate of matter as an empirical intuition.