40 GENERAL PHYSIOLOGY 



that science cannot exist without metaphysics. This fact cannot 

 be banished by the well-known method of the ostrich. 



It this appears to be a contradiction to contrast nature ((^vo-t?) 

 with something " beyond " nature {fiera rrjv (f>v(n.v). There is but 

 one world, whether this be termed nature, mind, reality, or anything 

 else. It follows also that there is but one kind of knowledge, and 

 not two. As soon, therefore, as the question arises of principles 

 and bases of knowledge, all artificial boundaries disappear. We 

 should not be deceived. The goal toward which the human mind 

 is striving in its theoretical investigations is not simply a 

 knowledge of the lifeless physical world or of living bodies, or of 

 this or that psychical phenomenon, but it is a knowledge of the 

 world. A division of labour among investigators, however, should 

 not only not be deprecated, but, because of the excessive multitude 

 of phenomena, should be encouraged ; nevertheless, the purely 

 supplementary purpose of such a division must be kept in mind, 

 and the artificial boundaries between the various fields of labour 

 must not be confounded with the natural boundaries. A severe 

 blow will be inflicted upon the coming centuries, if the gulf 

 between philosophy and science widens constantly from both sides ; 

 if, upon the one side, confused speculation, and, upon the other, 

 narrow specialisation constantly prevail and prevent a mutual 

 approach toward a beneficent common labouring-ground. Science 

 cannot make salutary advances without a philosophical working- 

 plan, and we see in the history of science that great discoveries 

 have been made, not by restricted specialisation, but by investi- 

 gators working philosophically, i.e., systematically, methodically, 

 and cognisant of their aim. But philosophy can obtain really 

 important results just as little by a purely speculative method, hy 

 not keeping close to established facts and not submitting its 

 speculations to the severe criticism of experience. The history of 

 science proves that true advance comes only by thoughtful 

 investigation. The above theoretical considerations regarding 

 knowledge ought to give us a basis for investigation such as every 

 thinking investigator sooner or later must make for himself, and 

 upon which he must build broadly and freely in order that his 

 labours may be fruitful. 



The most important result afforded by the above considerations 

 is the monistic standpoint, in accordance with which the world 

 appears as unitary, and the dualism of the physical world and mind 

 as an illusion. The fact, which appears so remarkable from other 

 standpoints, is, therefore, not surprising, that the laws that 

 control the physical world and those that control mental 

 phenomena are completely identical. This appears necessarily so 

 when we find that the phenomena of the physical world are 

 arranged according to space, time and causality, and when we 

 recognise therein the logical principles of our own thought ; the 



