242 THE WILL IN NATURE.
actions that follow upon external motives, and thus receiving impressions from inside upon which they react correspondingly, just as the brain receives representations on the strength of which it forms resolutions; only each of these minor centres is confined to a narrower sphere of action. Upon this rests the vita propria [proper life] of each system, in referring to which Van Helmont said that each organ has, as it were, its own ego. It accounts also for life continuing in parts which have been cut off the bodies of insects, reptiles, and other inferior animals, whose brain has no marked preponderance over the ganglia of single parts; and it likewise explains how many reptiles are able to live for weeks, nay even months, after their brain has been removed. Now, if our surest experience teaches us that the will, which is known to us in most immediate consciousness and in a totally different way from the outer world, is the real agent in actions attended by consciousness and directed by the chief centre of the nervous system; how can we help admitting that those other actions which, proceeding from that nervous system but obeying the direction of its subordinate centres, keep the vital processes constantly going, must also be manifestations of the will? Especially as we know perfectly well the cause because of which they are not, like the others, attended by consciousness: we know, that is to say, that all consciousness resides in the brain and therefore is limited to such parts as have nerves which communicate directly with the brain; and we know also that, even in these, consciousness ceases when those nerves are severed. By this the difference between all that is conscious and unconscious and together with it the difference between all that is voluntary and involuntary in the movements of the body is perfectly explained, and no reason remains for assuming two entirely different primary sources of movement: especially as principia praeter necessitatem non sunt multiplicanda [principles are not to be increased unnecessarily]. All this is
