Mr. Wallace has pointed out very clearly and conclusively the fallacious character of the evidence on which the old theory of instinct was founded. Starting with the notion that wild animals had none of that docility and versatility which man possesses through his reasoning powers, yet seeing them produce effects like those which man produces by the help of teachers or his own choice of means, we inferred the existence of as many separate faculties as there are kinds of animals. Each of these faculties was thought to resemble reason about as much as a jack-in-the-box resembles a man. The faculty came into exercise in one invariable way without any choice on its owner’s part, just as the jack starts up, whether he will or no, when his lid is taken off. We wondered at the admirable contrivance and design by which these very limited faculties were adapted in each case to the wants and preservation of the species to which they belonged. At times, it is true, with some inconsistency, we permitted ourselves to upbraid the goose with its stupidity; to speak of the sheep as silly, and the ostrich as wanting intelligence; we even expunged the dodo, with its self-preserving instinct, from the face of the earth; but in spite of these slips and mischances, we still kept gaping and wondering at our own explanation of things, and calling it an excessively wise and ingenious contrivance that every species of animal should have a separate faculty to itself, when one and the same faculty for them all would not only do just as well, but a great deal better. We were far from perceiving how strong a support to Materialism our theory involved, since if the lower animals without reason produce effects like those of reason, then effects like those of reason in a number of cases beyond calculation must be the result of bodily structure. It might not follow that the effects of reason itself were the results of bodily structure, but it would become startlingly probable.