THE EVOLUTION OF SOCIAL BEHAVIOUR 233 
entirely superseded, plays a subordinate part ; alongside the 
organic continuity which is due to physical heredity, there runs 
a continuity of tradition through social inheritance. 
Human civilization is an embodiment of reason, a product 
of reflection, a realization of ideals conceived by the leaders of 
mankind. All this forms the environment of each one of us. 
And it is this environment which is undergoing progressive 
evolution and playing on the rational faculties of those which 
are submitted to its moulding influence. There is no sufficient 
evidence of anything of the kind in the social communities of 
animals. This, of course, must be accepted merely as an 
expression of opinion. But on the hypothesis that animals 
are rational beings, capable of reflection, it is difficult to 
understand why they should remain at so low a level of social 
achievement. The absence of powers of descriptive intercom- 
munication is often assigned as the cause of their comparatively 
unprogressive condition ; but it may be regarded as the sign, 
rather than the cause, of their lack of reason in the more re- 
stricted sense of the term. We cannot, however, enter into 
the much-disputed question whether reason is the product of 
language, or language the outcome of reason. Perhaps the 
safest position is to assume that rationality and true speech are 
in large measure different aspects of one evolutionary move- 
ment—speech arising out of such preceding modes of communi- 
cation as were considered in the second section of this chapter ; 
reason developing out of intelligence which supplies its neces- 
sary data. It is sometimes said that, notwithstanding their 
powers of speech, savages in their social relations show little 
advance on animal communities. But surely such statements 
must be made in forgetfulness of the fact that savage customs 
almost invariably indicate the presence and sway of ideals which 
puzzle us from their quaintness, and from the fact that they 
seem contrary to the dictates of intelligence and due to motives 
and conceptions the nature and force of which we find it diffi- 
cult to estimate. The passage from intelligent social behaviour 
to the rationality which has assumed such strange aspects among 
existing savages took place somewhere at some time in the past ; 
