THE UNIQUE MAMMAL 23 



quite unsound biology. But up to a point he paints a true pic- 

 ture of the difficulties that inhere in the concept of personal 

 identity of a living organism. As he says (pp. 84-5): "Surely 

 all reasonable people will feel that an infant an hour before 

 birth, when in the eye of the law he has no existence, and could 

 not be called a peer for another sixty minutes, though his father 

 were a peer, and already dead, — surely such an embryo is more 

 personally identical with the baby into which he develops with- 

 in an hour's time than the born baby is so with itself (if the 

 expression may be pardoned), one, twenty, or it may be eighty 

 years after birth. There is more sameness of matter; there are 

 fewer differences of any kind perceptible by a third person; 

 there is more sense of continuity on the part of the person him- 

 self, and far more of all that goes to make up our sense of same- 

 ness of personality between an embryo an hour before birth 

 and the child on being born, than there is between the child 

 just born and the man of twenty. Yet there is no hesitation 

 about admitting sameness of personality between these two last. 



"On the other hand, if that hazy contradiction in terms, 'per- 

 sonal identity,' be once allowed to retreat behind the threshold 

 of the womb, it has eluded us once for all. What is true of one 

 hour before birth is true of two, and so on till we get back to 

 the impregnate ovum, which may fairly claim to have been 

 personally identical with the man of eighty into which it ulti- 

 mately developed, in spite of the fact that there is no particle 

 of same matter nor sense of continuity between them, nor recog- 

 nised community of instinct, nor indeed of anything which goes 

 to the making up of that which we call identity." 



Now keeping up the flow of matter and energy through the 

 organism means getting a living, in the literal and complete 

 sense of the words. Nearly all living things other than man get 

 their livings in one or the other of two ways, or by some com- 

 bination of them. These two methods are: 



A. By preying upon other organisms, plant or animal in na- 

 ture as the case may be. In general this is the animal way of 

 getting a living. 



