The World as Will and Idea, Vol. I — Arthur Schopenhauer, trans. Haldane & Kemp

1 call a cause, in the narrowest sense of the word, that state of matter, which, while it introduces another state with necessity, yet suffers just as great a change itself as that which it causes ; which is expressed in the rule, “ action and reaction are equal.” Furtlier, in the case of what is properly speaking a cause, the effect increases directly in proportion to the cause, and therefore also the reaction. So that, if once the mode of operation be known, the degree of the effect may be measured and calculated from the degree of the intensity of the cause ; and conversely the degree of the intensity of the cause may be calculated from the degree of the effect. Such causes, properly so called, operate in all the phenomena of mechanics, cheniistry, and so forth ; in short, in all the changes of unorganised bodies. On the other hand, I call a stimulus, sucli a cause as sustains no reaction proportional to its effect, and the intensity of which does not vary directly in proportion to the intensity of its effect, so that the effect cannot be measured by it. On the contrary, a small increase of the stimulus may cause a very great increase of the effect, or conversely, it may eliminate the previous effect altogether, and so forth, f All effects upon organised bodies as such are of this kind. All properly organic and vegetative changes of the animal body must therefore be referred to stimuli, not to mere causes. But the stimulus, like every cause and motive generally, nevei determines more than the point of time and space at

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which the manifestation of every force is to take place, and does not determine the inner nature of the i'orce itself which is manifested. This inner nature we know, from our previous investigation, is will, to which tlierefore we ascribe botli the unconscious and the conscious changes of the body.

The stimulus holds the mean, forms the transition between the motive, wliich is causality accompanied throughout by knowledge, and the cause in the narrowest sense. In particular cases it is sometimes nearer a motive, sometimes nearer a cause, but yet it can always be distinguished from both.

Thus, for example, the rising of the sap in a plant follows upon stimuli, and cannot be explained from mere causes, according to the laws of hydraulics or capillary attraction ; yet it is certainly assisted by these, and altogether approaches very near to a purely causal change.

On the other hand, the movements of the Hedysarum gyrans and the Mimosa pudica, although still following upon mere stimuli, are yet very like movements which follow upon motives, and seem almost to wish to make the transition.

The contraction of the pupils of the eyes as the light is increased is due to stimuli, but it passes into movement which is due to motive ; for it takes place, becatise too strong lights would affect the retina painfully, and to avoid this we contract the pupils.

The occasion of an erection is a motive, because it is an idea, yet it operates with the necessity of a stimulus, i.e., it cannot be resisted, hut we must put the idea away in order to make it cease to affect .us. This is also the case with disgusting things, which excite the desire to vomit.

Thus we have treated the instinct of animals as an actual link, of quite a distinct kind, between movement following upon stimuli, and action following upon a known motive. Now we might be asked to regard breathing as another link of this kind. It has been disputed whether it belongs to the voluntary or the involuntary movements, that is to say, whether it follows upon motive or stimuTHE OBJECTIFICATION OF THE WILL.

lus, and perhaps it may be explained as something which is between the two. Marshall Hall (“ On the Diseases of the Nervous System,” § 293 sq.) explains it as a mixed function, for it is partly under the influence of the cerebral (voluntary), and partly under that of the spinal (non-voluntary) nerves. However, we are finally obliged to number it with the expressions of will which result from motives.

For other motives, i.e., mere ideas, can determine the will to check it or accelerate it, and, as is the case with every other voluntary action, it seems to us that we could give up breathing altogether and voluntarily suffocate. And in fact we could do so if any other motive influenced the will sufficiently strongly to overcome the pressing desire for air. According to some accounts Diogenes actua,lly put an end to his life in this way (Diog.

Laert VI. 76). Certain negroes also are said to have done this (F. B. Osiander “ On Suicide ” [ 1 8 1 3] pp. 170-180). If this be true, it affords us a good example of the influence of abstract motives, i.e., of the victory of distinctively rational over merely animal will.

For, that breathing is at least partially conditioned by cerebral activity is shown by the fact that the primary cause of death from prussic acid is that it paralyses the brain, and so, indirectly, restricts the breathing; but if the breathing be artificially maintained till the stupefaction of the brain has passed away, death will not ensue.

We may also observe in passing that breathing affords us the most obvious example of the fact that motives act with just as much necessity as stimuli, or as causes in the narrowest sense of the word, and their operation can only be neutralised by antagonistic motives, as action is neutralised by re-action.

For, in the case of breathing, the illusion that we can stop when we like is much weaker than in the case of other movements which follow upon motives ; because in breathing the motive is very powerful, very near to us, and its satisfaction is very easy, for the muscles which accomplish it are never tired, nothing.