The Ascent of Man 167 



It may be urged that we are attaching too much importance 

 to the arboreal apprenticeship, since many tree-loving animals 

 remain to-day very innocent creatures. To this reasonable objec- 

 tion there are two answers, first that in its many acquisitions the 

 arboreal evolution of the humanoid precursors of man prepared 

 the way for the survival of a human type marked by a great step 

 in brain-development; and second that the passage from the 

 humanoid to the human was probably associated with a return to 

 mother earth. 



According to Professor Lull, to whose fine textbook, 

 Organic Evolution (1917), we are much indebted, "climatic con- 

 ditions in Asia in the Miocene or early Pliocene were such as to 

 compel the descent of the prehuman ancestor from the trees, a 

 step which was absolutely essential to further human develop- 

 ment." Continental elevation and consequent aridity led to a 

 dwindling of the forests, and forced the ape-man to come to earth. 

 "And at the last arose the man." 



According to Lull, the descent from the trees was associated 

 with the assumption of a more erect posture, with increased libera- 

 tion and plasticity of the hand, with becoming a hunter, with ex- 

 periments towards clothing and shelter, with an exploring habit, 

 and with the beginning of communal life. 



It is a plausible view that the transition from the humanoid 

 to the human was effected by a discontinuous variation of con- 

 siderable magnitude, what. is nowadays called a mutation, and 

 that it had mainly to do with the brain and the vocal organs. But 

 given the gains of the arboreal apprenticeship, the stimulus of an 

 enforced descent to terra firma, and an evolving brain and voice, 

 we can recognise accessory factors which helped success to suc- 

 ceed. Perhaps the absence of great physical strength prompted 

 reliance on wits; the prolongation of infancy would help to edu- 

 cate the parents in gentleness; the strengthening of the feeling of 

 kinship would favour the evolution of family and social life of 

 which there are many anticipations at lower levels. There is 



