Chapter 1

Concerning External Perception

: All our external perception presupposes, firstly, an activity of the mind which is checked and which we call sensation; secondly, an activity of the mind which gives to this felt sensation an infinitely divisible extension and which we call contemplation; and, thirdly, an activity of the mind which objectivates the thus extended sensation and asserts it to be an external thing, and which we call thinking.

The essence of all science consists in this: that we proceed from something sensuously perceived to its supersensuous ground. It is precisely so with philosophy. Philosophy starts from the perception of knowledge through the inner sense and proceeds to its ground. In the present series of lectures we shall be busied with the first part of this science, with the phenomenon. It is this phenomenon which we propose systematically to observe, and it will be my duty to guide your observation.

It is true that to observe knowledge means also to represent it not in its immediate living Being, but in only the picture of this Being. It will be my duty to guide you in the sketching of this picture, to separate what is to be separated, and call your attention to what is important. It will be necessary very often to appeal to a special artistical arrangement in order that consciousness should reply to the very same question we propose to it; and thus the merely natural observation will change into an artificially constructed experiment.

The general and major parts, into which this our observation may separate, cannot be fixed at the very beginning, but can be determined only by continued investigation. Until then it will be sufficient to imagine our course of lectures divided firstly into a chapter: Concerning the Facts of Consciousness in the Perception of External Objects. The expression, external objects, is used here just as common sense uses it, that is, objects, which are perceived by us as external to us, in space.

Our problem now is, to analyze the to us all well-known fact of this perception in general and according to its several components. I maintain—and request you all to look into your own consciousness and see whether you do not find it likewise—that in this fact are contained.

A.

An Affection of the External Sense;characterized by the following terms of language: red, clear-sounding, bitter, cold, &c.

The possibility of such an affection presupposes an external sense. It is, for instance, impossible that a blind man should be affected by colors. But it is also to be observed, that this affection itself is a limitation of the general sense to be affected in this particular manner. For instance: “I perceive this flower to be red” means simply, that my seeing in general, and particularly my seeing of this color, is limited by that particular seeing of a color which the habit of language designates as red.

B.

An Extension in Space.—And I maintain, and request you to verify and recognize, that these two parts, the Sensible and Extension, completely exhaust the essence of an external object.

1. I assert that extension is by no means a sensation, but utterly different from it. To perceive this clearly, I beg you to undertake the following consideration. Red, for instance, is an altogether simple sensation, and to objectivate it, as it were, from out of our mind, a mere mathematical point would be sufficient.

Now, what is it that impels and justifies you to spread out this simple and self-same remaining sensation of red over a large space, which is precisely so large and no larger, and upon which this red color is perhaps closely limited by an adjoining other color?

2. What, then, is extension, since it is evidently not sensation? It cannot be easy to answer this question, since it has been answered wrongly and in the most various manner until the present age, and since it was chiefly the correct answering of this question (through Kant) which led philosophy upon the right track.^[1]

In order to find the right answer in your own self, please assist me in the following artificial experiment, this being the first place where we need one: I ask you, whether that body perceived by you is divisible infinitely, or whether such an attempted and continued divisibility would finally find somewhere a limit where it could not be pursued any further? I foresee that you will not be able to reply otherwise than that the body is most truly divisible infinitely.

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