486 The American Naturalist. [j une , 



threefold definition of ideas to which he gives several names. 

 It will make the question clearer if we take three of these 

 names and speak of simple, complex and abstract ideas ; or of 

 percepts, recepts and concepts. 



This definition can be illustrated by taking the word "star." 

 The recognition of one particular star is a simple idea or 

 precept ; the recognition of a number of stars, or of bright 

 twinkling objects resembling the shining of stars, is a complex 

 idea or recept. So far the mind of the higher brutes keeps 

 pace with the developing mind of man. But the next step 

 carries us beyond the mental powers both of infants and of 

 animals : neither can conceive the idea of a star as present to 

 the mind of an astronomer. This is an abstract idea or con- 

 cept, and is unattainable except through the medium of articu- 

 late language. Where the child sees a twinkling spark, the 

 astronomer is conscious of a naming sun ; where, until lately, 

 men recognized the symbol of unchangeableness, the 

 astronomer knows he beholds stupendous worlds rushing 

 through space at unimaginable speed ; where the Hebrew seer 

 beheld " lesser lights " stuck in a solid firmament solely for the 

 service of man, the astronomer knows that his eye beholds 

 objects at a distance of millions upon millions of miles, objects 

 whose grandeur throws our whole solar system into insignifi- 

 cance. An abstract idea is in itself capable of containing a 

 volume of knowledge ; its capacities have hardly any limits 

 but that of the mind itself. Think only of the world of con- 

 cepts contained in the words "political economy," "verte- 

 brata," " liberty," " Aryan Race," " mythology," " ethics," and 

 we see how far civilized man has outstripped, not only the 

 lower animals, but the young of his own race and the savage ; 

 but the break is not at the minds of the lower animals. Rather 

 there is no break, but a gradual evolution. 



We may take as another instance of simple, complex and 

 abstract ideas the idea of one particular dog in the mind of 

 the child; the idea of dogs in general, extended to figures or 

 pictures of dogs ; and the ideas of the genus " Canis " as pres- 

 ent to the mind of the zoologist. The first and second con- 

 to the young child and the lower ani- 



