FUNDAMENTAL EXPLANATION OF THE ORIGIN OF THE OBSCURITY OF IDEAS IN WHAT RELATES TO CAUSALITY.
116. It may be asked, of what nature is this connection of the terms of the series;howone communicates with another;whatit is which is communicated; by virtueof what qualitythey are placed in relation. All these questions arise from a confusion of ideas which has been the occasionof interminable disputes. In order to avoid them we must remember the difference between intuitive and discursive knowledge, and between determinate and indeterminate, intuitive and not-intuitive ideas, as explained in its proper place.[82]
117. I there said[83]that the pure intellect may exercise its functions by indeterminate ideas, or those representing general relations which are not applied to any real or possible object, until a determination furnished by experience is added to them.[84]The idea of cause is indeterminate;[85]and, consequently, taken in general, it cannot be presented to us without the relation of being and not-being, or of beings united among themselves by a certain necessity, but in an absolute indeterminate manner.[86]Therefore the idea of cause is not enough to determine the character of this activity and its means of communication; this idea by itself can tell us nothing of the particular; it can only teach us certain truthsa priori; the application of these truths to beings rests on experience.
118. I said[87]that our intuition is confined to passive sensibility, active sensibility, intelligence, and will; whatever lies outside of this sphere we can know only by indeterminate conceptions, and, consequently, it is impossible for us to expose to the intuition of another that which we feel to be wanting to our own. We may develop this doctrine farther by applying it to the philosophical questions on causality.
119. There have been great disputes as to whether bodies exercise a true action on each other; and those who hold the negative are always asking,howone body can causeany thing in another?whatthat is which is transmitted, and what is thecharacterof its active quality? Various replies have been made; but I greatly doubt if it is possible to make any which is satisfactory, without considering the doctrine which I have just explained,—what answer, then, can be made? It is this: we know nothing intuitively of bodies except passive sensibility, which, in the last result, is only extension with its various modifications.[88]Now these modifications are reduced to figure and motion; whatever would make us depart from these two intuitions, requiring an explanation with characteristic determinations, would ask for that which is beyond the power of man. The limits of our intuition on this point are confined to extension and motion, and their relations to our sensibility; we must, therefore, be contented with observing the phenomena of bodies, and subjecting them to calculation within the circle of this intuition: all beyond this is impossible. We know that the body A moves with a certain velocity, which we measure by the relation of space to time; when it arrives at the place where it meets B, B moves in a corresponding direction and with a corresponding velocity. Here there is a succession of phenomena in time and space; the phenomena are subject to constant laws, which are known by experience. Our intuitive cognitions go no farther; when we attempt to go beyond this we find the general relations of being and not-being, of beingbeforeand beingafter, of condition and conditioned, which present nothing determinate by which we can explain the true character of secondary causality.
120. Philosophy, when treating of bodies, is limited to what is strictly called physics; when it attempts to rise to the region of metaphysics bodies disappear, in so far as theyare phenomena subject to sensible observation, and there remains only the general and indeterminate ideas of them.
121. As regards the sensitive faculty, we are in some sort passive, inasmuch as we receive the impressions which we call sensations. Whatever activity we possess in sensation does not depend on our free will, supposing that we are subject to the conditions of sensibility. If you put your hand in the fire it is impossible for you not to experience the sensation of heat. In what regards the causality which we have as to the reproduction of past sensations or the production of new sensible sensations, it is vain to ask us themannerin which we exercise this activity: its exercise is a part of consciousness; all we know about it is that it exists in such or such a manner in our consciousness.
122. The same may be said of the elaboration of ideas. None of the philosophers can explain themannerof this immanent production; ideological investigations go no farther than the characterizing and classifying these phenomena and showing the order of their succession; they can tell us nothing concerning the manner in which they are produced.
123. The exercise of the will presents to our intuition, or if you please, to our consciousness, another series of phenomena, of the manner of the production of which we know nothing. Consciousness testifies that the free principle which exercises this activity is within us: this is all that we know about it. These phenomena are found at times connected with motions of our bodies, which a constant experience presents as depending on our will, but how things so different are connected, we know not: philosophy will never know.