This remark is useful only in showing our natural incapacity for experiencing a sensation, of whatever kind, without connecting it with an external object possessing corresponding attributes to the sensation, and which was its cause.
In any case the truism is not to be ignored, since Aristotle, great philosopher as he was, did not consider it beneath his dignity to employ it. He said: “I think of a stone; the stone is not in my mind, but its form is.”
To prove to common-sense that its remark has no connection with the thesis recently laid down, would serve no good purpose. A personal mental act, if it be lawful to personate a quality, would alone convince common-sense of its error; but when once convinced common-sense would then have changed to something higher than it had previously been. It will have mounted up one stage towards reason, and in following this route under the guidance of increasing reason, it will end by understanding this truth as demonstrated by Kant: he who cannot distinguish a real object from its representation will never understand the working of the human mind.
The importance of this truth must excuse my digression.
Metaphysics.
The name of Kant will always be intimately connected with the word metaphysics, not because he buried himself in it, as some have supposed who only know his system of philosophy by hearsay; but because his labours consisted in forbidding reason to approach this science which is constantly threatening to invade it, and to get the upper hand by putting itself in its place.
Kant was the first to trace with decision the line of demarcation between the knowledge of which our reason is capable, and that of which it is incapable. No one has drawn so sharp a line between the knowable and the unknowable; this was to explain metaphysics. Alfred Fouillée has defined them as “the critical study of problems which the mind seeks to unravel from a necessity of its nature, although another necessity of its nature renders it incapable of solving them”—such is metaphysics.
This definition is excellent, but for those who make no preparatory studies in philosophy it would present itself rather in this form. If certain questions are of necessity presented to the mind which it finds it impossible to solve, it follows that the mind would necessarily contradict itself. Thus this succinct definition of Fouillée requires to be itself defined.
Noiré, whilst giving more details, is also more exact. “Metaphysics is only explained on the condition that we understand the nature of our power of understanding, in so far as, on the one part, this power is actively manifested in experience, and secondly, in so far as it possesses anteriorly to any experience, and to anything observed, certain ideas without which there could not possibly or even conceivably, be any impression made in the human mind.” I am afraid that this explanation of Noiré will also be lost upon those who are not experienced in the subject.
The explanation of Schopenhauer is not less definite, and is more concise than the two preceding. The foundation upon which all our knowledge and all our science rests, is the incomprehensible—I fancy that the uninitiated will be equally unable to understand this.