72 THE FOUNDATIONS OF ZOOLOGY 



lead one to expect, we have no reason to expect these things to take 

 place in the absence of these stimuli or some equivalent. 



If the believer in innate ideas tells us all this is quite con- 

 sistent with his principles; if, while admitting that he knows no 

 mental act or state without physical concomitants, he assert that 

 the subjective or mental aspects of our responsive actions arise 

 in us because of our inherent nature ; if he tell us that the physi- 

 cal concomitants are only the " occasion " of the mental states, or 

 the stimulus under which they arise in our minds, — I do not see 

 why the zoologist should not agree, and admit that he is, to this 

 extent, an intuitionist after the ancient school of Plato ; for, so 

 far as science tells us, what we call the "causes" of physical 

 events are no more than "occasions." In physical science all 

 we mean, when we say we understand a thing, is that, certain 

 conditions or occasions being given, it may be counted on with 

 confidence, while we cannot judiciously expect it in their absence. 



The question at issue between the Lamarckian and the Dar- 

 winian is not whether knowledge arises in the mind in the 

 absence of experience, but whether experience is anything more 

 than the " physical cause," or occasion, or stimulus, in the pres- 

 ence of which knowledge may be expected to arise in the mind, 

 and in the absence of which it cannot reasonably be looked for. 

 If this latter is the case, is it not hard to see how experience 

 can be either the efficient or the physical cause of the mind in 

 which it arises } 



It is hard to calmly ask whether training and education and 

 experience add anything to our nature, for we know that a man 

 educated is different from the same man uneducated. If, at first 

 thought, the question seems repugnant to common sense, we 

 must remember that it is also hard, when looking through a bit 

 of colored glass at a neutral wall, to believe that no color is 

 added, and that the effect is due to negative and passive ex- 

 clusion by selection or sifting. 



The assertion that there is no more redness on the wall, or 

 on the retin^., than there was before the red glass was interposed, 

 seems, at first, to be contradicted by our sensations, and repug- 

 nant to common sense. 



Who can imagine more color outside the limits of a rainbow 



