Page:On the Fourfold Root, and On the Will in Nature.djvu/267

 PHYSIOLOGY AND PATHOLOGY. 235

The three assumptions which are criticised by Kant in his Transcendental Dialectic under the names of Ideas of Reason, and have in consequence since been set aside in theoretical philosophy, had always stood in the way of a deeper insight into Nature, until that great thinker brought about a complete transformation in philosophy. That supposed Idea of Reason, the soul: that metaphysical being, in whose absolute singleness knowing and willing were knit and blended together to eternal, inseparable unity, was an impediment of this sort for the subject-matter of this chapter. As long as it lasted, no philosophical Physiology was possible: the less so, as its correlate, real, purely passive Matter, had necessarily also to be assumed together with it, as the substance of the body. 1 It was this Idea of Reason, the soul, therefore, that caused the celebrated chemist and physiologist, Stahl, at the beginning of the last century to miss the discovery of the truth he so nearly approached and would have quite reached, had he been able to put that which is alone metaphysical, the bare will as yet without intellect, in the place of the anima rationalis [rational soul]. Under the influence of this Idea of Reason however, he could not teach anything but that it is this simple, rational soul which builds itself a body, all whose inner organic functions it directs and performs, yet has no knowledge or consciousness of all this, although knowledge is the fundamental destination and, as it were, the substance, of its being. There was something absurd in this doctrine which made it utterly untenable. It was super seded by Haller's Irritability and Sensibility, which, to be sure, are taken in a purely empircial sense, but, to make up for this, are also two qualitates occultae [occult qualities], at which all explanation ceases. The movement of the heart and of the intestines was now attributed to Irritability. But the anima rationalis still remained in undiminished honour

1 As a being existing by itself, a thing–in–itself. [Add. to 3rd ed.]