“The Limits of Animal Intelligence”

Abstract

CLOSELY in connection with an observation I made the other day with respect to an argument of Prof. Pearson's, I should like to say a few words about a paper read by Prof. Lloyd Morgan before the International Congress of Experimental Psychology, on “The limits of animal intelligence.” The first proposition he advanced, “That human psychology is the only key to animal psychology,” and the deductions he subsequently drew, all implied that our knowledge of human psychology differed not only in degree, but in kind, from our knowledge of that of animals. Of course it is true that my knowledge of my own psychology does differ in kind from my knowledge of that of animals, but it differs in exactly the same way from my knowledge of that of all other men. If in no case is “an animal activity to be interpreted as the outcome of the exercise of a higher psychical faculty, if it can be fairly interpreted as the outcome of one which stands lower on the psychological scale,” the same rule should be applied to the interpretation of human activities, for the only reason for distinguishing between human and animal psychology is that their activities do, as a matter of fact, differ. Human beings are of course distinguished from animals in other ways; in the structure of their limbs, for example; but there is no a priori ground for inferring from such differences any, and certainly not any particular, difference in psychological powers. And so far from its being permissible to infer such a difference from greater or less complexity of brain-structure, it is only because animals which when alive displayed great activities proved, on dissection, to have possessed complex brain structure, that we can infer any connection whatever between the two phenomena. As no man has ever dissected his own brain he cannot say that any particular structure is associated with those psychological powers of which alone he has any more direct knowledge. If, for example, I say “Morality involves a perception of the relation between the actual and ideal, and is based on introspection,” I say this in consequence of my personal experience. I can only infer morality, introspection, and so on, in other beings, whether animals or men, by judging from their activities. And if “most cases of so-called morality in the dog can be otherwise interpreted,” so also can most cases in other men. A fundamental distinction between the psychological powers of animals and men could only be established by showing a fundamental distinction between animal and human activities, as observed from outside by a third person. And though it is easy to show that there is a difference in degree, Prof. Morgan did not adduce any cases which even tended to show that there is any difference in kind. The cases he did adduce all tended the other way; and though this was doubtless because he only adduced difficult cases in order to show that his theory was capable of explaining them away, his explanations seemed to me, for the reasons I have given, insufficient.