THE CAUSATION OF DISEASE. 3 



little to us, so long- as the conclusions deducible from this 

 assumption shall aid us in the practical concerns of life. The 

 physician can have nothing to say to any portion of philosophy 

 which cannot be reconciled with utilitarianism ; but, although 

 I would gladly escape the psychological aspect of the question, 

 it is advisable to state — very briefly — wherein the a,bove defini- 

 tion of cause is psychologically deficient. 



First, the definition assumes a material world, but it is 

 utterly impossible to prove the existence of such material 

 world, since we have no knowledge of anything but our own 

 mental states. Of anything outside of or apart from mind, we 

 can know nothing. Inasmuch, however, as the assumption of 

 a material world and of material conditions, as above defined, 

 by no means interferes with the conclusions based thereon, so 

 far as they affect the practical conduct of daily life, we are at 

 perfect liberty to assume the existence of a material world. I, 

 therefore, unhesitatingly speak of material conditions, although 

 it would be psychologically more correct to speak of phenomena 

 — of that which seems to be (= the phenomenal) as dis- 

 tinguished from that which is (= the noumenal). 



A second point which, from the psychological point of view, 

 deserves notice, is that no mention is made of " Force " among 

 the material conditions. Our conception of force is the mental 

 ingredient out of which our conceptions of matter, space, 

 time, and motion are built.* It will only be necessary to refer 

 to the first two of these. Matter is ultimately known to us 

 through its manifestations of force, through the resistance, 

 namely, which it opposes to our muscular energies. This 

 resistance is twofold ; for, first, matter resists our efforts to 

 push it out of position, and is capable of pushing us out of 

 position — whence arises the idea of repulsion ; and, secondly, 

 it resists our efforts to rend its several parts asunder 

 (= cohesion), and hence arises the idea of attractive force. 

 We conceive of force, therefore, as something which attracts 

 and repels. A little thought will show that matter can only 

 be known to us through its manifestation of force (= resist- 

 ance), for '-abstract this, and nothing but empty extension 

 remains." But, on the other hand, we cannot think of force 



* Vide Herbert Spencer's " First Principles," § 50. 



B 2 



