For these and other reasons, ancestor worship is not often found in its pure and simple form, but is usually complicated and modified in at least two important ways:--(1) a single ancestor is selected as the originator and founder of the family, the high patriarchal attributes being for the most part reserved for him alone; (2) this same ancestor is regarded as the founder, not merely of a single family, but of the whole clan, tribe, nation or other social unit, or, by a further extension, of the whole human race, of all living beings or, ultimately, of the whole Universe. There is thus created the notion of a single All-Father, who serves at once as the supreme and most satisfying embodiment of the father-ideal for the individual and as a potent means of strengthening and uniting the community through the sense of brotherhood and loyalty that attaches to a common worship and a common origin from a divine ancestor. The satisfying character of the religious concept that is here reached is apt to be still further increased by a complete or partial fusion of the notion of the divine father with that of the kingly father which we have already discussed. The mythical divine ancestor, the founder of the race, is frequently supposed to have been originally a king also, and it is usual for the reigning line of sovereigns to trace their descent more especially from him. Very often too the kings, or at any rate the greater ones among them, receive divine honours at their death, being then worshipped along with the other illustrious ancestors of the tribe, having but exchanged their earthly power for a more exalted throne in heaven.
It is in the early stages of tribal ancestor worship of the kind we have been here considering that we come across a widespread social and religious system so curious in nature that it may undoubtedly rank as one of the most remarkable discoveries brought about by the study of primitive man. I refer, of course, to Totemism. In Totemism the mythical ancestor takes on a non-human form, being as a rule some animal, but sometimes also a plant or even an inanimate object. All examples of the totem class are, as a rule, held sacred by those who belong to the respective totem, and must be treated with care and reverence, but (in the case of animal totems at any rate) are sometimes killed and eaten at a solemn sacrificial feast. Combined with these religious or quasi-religious manifestations of Totemism there are usually to be found certain well marked features of social organization. A single totem is not, as a rule, common to a whole tribe, but each tribe consists of two or more (most often four, but sometimes as many as eight) totem clans, which are all strictly exogamous, no man being allowed to take a wife from his own clan; the field of choice being indeed sometimes still further restricted, in such a way that the women of only one small section of the total tribe are available for this purpose. The sociological and psychological influences that led to the creation of the totemic system in a number of widely separated parts of the world are still to a large extent a matter of dispute. A number of theories have been propounded on the subject, and although many of them are suggestive, there is perhaps no single one as that fully and satisfactorily accounts for all the facts[166]. Among the few points that emerge clearly from the investigations and discussions to which the matter has given rise is the connection of the totem with the father. It has been shown that the totem spirit regularly, either to a complete or to a partial extent, plays the father's part in the creation of the child; the substitution of totem for father being rendered easier by the existence of a confused and ignorant state of mind on the subject of paternity; which makes it conceivable that the spirit of an animal or other object should enter into the mother's womb and thus produce conception[167].