348 MIND IN EVOLUTION CHAP. 



justify those assumptions in an incomplete manner. A 

 chicken avoids a caterpillar because he dislikes the taste. 

 We perhaps refuse to allow that the chicken reasons be- 

 cause he does not know what it is that makes the cater- 

 pillar taste bad. After the chicken follows the chemist, 

 who finds that the caterpillar secretes a certain acid. We 

 clap our hands and applaud him as a reasoner who has ex- 

 plained everything. But will the chemist explain why a 

 given acid should have an acrid taste, or show how the 

 experience of unpleasantness should modify subsequent 

 action ? A horse learns to lift a latch. We do not think 

 he reasons. He merely has found out how it is done, and 

 does it. A man explains to a child the action of the latch, 

 and shows how by pressing it at one point you lift it out 

 of a catch at another. He, we say, reasons because he 

 analyses the process and how it is done. But a physicist 

 might point out that the man knows nothing whatever 

 about it unless he sees that the principle of the lever is 

 involved in a simple form, and a metaphysician might add 

 that the physicist cannot be said to understand the prin- 

 ciple of the lever unless he is prepared to decide whether 

 it is a principle which holds true of reality, and if so, on 

 what epistemological grounds. 



If we allow reason to the human species in general, and 

 yet restrict it to that species, it must be by identifying the 

 term reason arbitrarily with a certain grade in the develop- 

 ment of analysis. It would be true to say that abstract or 

 explicitly general reasoning emerges in the level of intelli- 

 gence under consideration, but we have seen that abstract- 

 ness is only one side of generality, and that the generality 

 of human as opposed to animal reasoning is once more 

 primarily a matter of explicitness. At bottom the function 

 of mind in this as in the lower stages is to organise life by 

 the correlation of experiences. As in every stage of mental 

 growth what is new is that the work of the mind becomes 

 on the one hand more explicit or articulate, on the other, 

 more comprehensive in scope. That these two move- 

 ments, if not at bottom identical, are closely interwoven, 

 is seen in the relations of analysis to comparison. We 

 clear up our experiences by bringing them into relation, 



