It is not surprising therefore that religion, capable of creating in modern times those moral societies called "Churches," should, in all ages, have been the strongest bond of natural societies, primitive families, savage tribes, great empires, civilised peoples. The first stone of every hearth was a sacred stone. The first tombstone was a monument of piety, and burial is an essentially religious ceremony. Before they were regarded as protectors without, tribal gods were the internal bonds of the tribe itself. All the individuals of the tribe saw in the god a father and an ever present head, so that religion came to double by this moral kinship their blood relationship. In this matter the great civilisations do not differ from the rest. All have a religious soul that differentiates and explains them. It is not merely morals and philosophy that are affected by religion, but literature, art, politics, social economy, and in a general way the whole destiny of men. The secret of a race is hidden in its religion. It is there that the forces of life and resistance to the causes of dissolution are concentrated.... Let us enter with deep piety therefore on the history of religion on the earth.... That history is still in embryo. The comparative study of religions has arisen within our time; it is still at its beginnings.... The idea of religious progress is a great and luminous idea, but it is not possible to apply it to all the details of history. Progress has not taken place along a single or continuous line.... On four or five points the progress is undeniable; it must suffice to point them out and mark their direction in order that we may foresee the supreme end to which this faltering and laborious march is tending. In religions there are differences of degree and differences of kind: the one mark in the scale of evolution the successive movements of the religious consciousness in time; the others express the diversity and simultaneity of religions in space. The first are explained by inequalities of moral development; the second by variety of races, climates, civilisations. Take, for example, the Hebrew tradition; follow it in broad outline, and you will note religious forms which give birth one to another and constitute an historical development--the religion of the ancient Beni-Israel, prophetism, rabbinical pharisaism, Christianity, Mohammedanism: there, in a continuous evolution, you have what may be called differences of degree. But, on the other hand, consider the Mongolian or Chinese religions, those of ancient Mexico, of India, Egypt, or Greece: you have differences of kind which you cannot classify in a single scale. And, as some of these peoples have disappeared, and others been arrested in their growth, and as they have never marched abreast, it is impossible to compare them or to put into one category the religious forms which their history presents. But some attempt must be made to trace them out.