236 THE PRINCIPLES OF HEREDITY 



If a bird, for instance, attacked by a man, escaped, and sub- 

 sequently fled on sight of the man without waiting to be 

 attacked, it must draw a real inference. It must conclude, 

 in a dim way at least, that the man is dangerous. If reason 

 is used with this meaning it is certainly incorrect to say that 

 men alone possess it. If, however, we limit the term to 

 some particular manifestation, or phase of the faculty of 

 drawing inferences, it may be correct to say that man is the 

 only rational animal. Owing to his immense memory and 

 his vast powers of using the contents of his memory, he is, 

 of course, able to perform feats of thinking, abstraction, for 

 example, far beyond the powers of lower animals. But even 

 in its highest manifestations the faculty differs in degree, not 

 in kind, from that displayed by the oyster, which learns 

 by experience to close its shell when uncovered by water. 

 The oyster draws a kind of inference, however dimly and 

 unconsciously ; in it, as in a baby lately born, is present the 

 beginnings of that faculty which attains to such splendour in 

 adult man. The baby is as incapable as the oyster of the 

 higher phases of reasoning, but as he grows, as he recapitu- 

 lates the life-history of his race, the development of the 

 faculty in him proceeds without stop or break, from the 

 lowest phases of perceptual inference to the highest flights of 

 conceptual or abstract thought, and thus affords a represent- 

 ation of the manner of its evolution. 1 



1 Many writers, especially when animated by theological zeal, have 

 declared that the possession of reason fixes an impassable gulf be- 

 tween man and the lower animals. Thus Father Mayer (Fortnightly 

 Review, Feb. 1902, p. 222), who defines reason as "the faculty, the 

 essential character of which consists in the apprehension of the uni- 

 versal," insists that "the lower animals do not show that individual 

 free variation in method and plan of action, and that intellectual pro- 

 gress which ought to mark the presence of personal intelligence. Thus, 

 animals of the same species when in similar circumstances exhibit a 

 striking uniformity in their operations. They will seek their prey, 

 build their nests, and foster their young in the same way. Amongst 

 rational beings, on the contrary, we find in everything the signs of 

 individual personality. The ants and bees in the time of Moses or of 

 Aristotle worked as perfectly as their descendants of to-day, and geese 

 and sheep acted not more awkwardly. There is no evidence that during 

 all the time brutes existed upon the earth they have invented a single 

 mechanical instrument, lit a fire, or intelligently transmitted a useful 

 piece of information from one generation to another. . . . The differ- 

 ence which separates the simplest exercises of reason from the highest 

 forms of animal intelligence is thus found to be impassable." 



But, as we see, reason, even as defined by Father Mayer, is plainly 

 nothing more than a particular development of the faculty for making 

 and using mental acquirements. In man alone this faculty has grown 

 so great that he is able to apprehend universals. It would be as reason- 



