20 Presidential Address.
closely related to the problem of the influence of the relative shares taken in the production of mental events by heredity and social heritage. If we find that certain symbols are really universal, there would be at least a prima facie case for the influence of heredity. If, on the other hand, no such universality is found, we shall have to look to social heritage for our explanation of the prevalence of the same mode of symbolism among different peoples or among the dift"erent members of one people.
Closely connected with this problem is another, which is now prominent in the thoughts of students of human custom, concerning the part taken by diffusion. If we should succeed in finding the universal distribution of a symbol there would remain the further question whether it was universal because through heredity it had become part of the inherent equipment of the human mind, or whether the use of the symbol has been carried about the world by the movements of some body or bodies of men in whose system of thought the symbol was prominent. As has been pointed out by those who hold the former view, if it were found that the use of a symbol is indeed universal, the question whether it has been diffused or not is of no great importance, for we could hardly expect the use of a symbol to receive universal acceptation unless there was some disposition universally present in the human mind which made the use of the symbol fitting and natural. If, however, we find that the use of a symbol is not universal, and still more if we find that the peoples who use it show other clear evidence of influence from without, the fact of diffusion becomes of great significance, and the probability greatly in favour of the view that, wherever it is found, it is part of the social heritage.
I can now turn to the special instance which I have chosen to illustrate this subject, and shall examine the distribution of the symbolism of rebirth in ceremonial to see how far it is universal, and whether its distribution has
