Nature, therefore, we shall presume, having given to every animal its mode of existence, its dispositions and manner of life, has dealt equally with the human race; and the natural historian who would collect the properties of this species, may fill up every article now as well as he could have done in any former age. The attainments of the parent do not descend in the blood of his children, nor is the progress of man to be considered as a physical mutation of the species. The individual, in every age, has the same race to run from infancy to manhood, and every infant, or ignorant person, now, is a model of what man was in his original state. He enters on his career with advantages peculiar to his age; but his natural talent is probably the same. The use and application of this talent is changing, and men continue their works in progression through many ages together: they build on foundations laid by their ancestors; and in a succession of years, tend to a perfection in the application of their faculties, to which the aid of long experience is required, and to which many generations must have combined their endeavours. We observe the progress they have made; we distinctly enumerate many of its steps; we can trace them back to a distant antiquity, of which no record remains, nor any monument is preserved, to inform us what were the openings of this wonderful scene. The consequence is, that instead of attending to the character of our species, where the particulars are vouched by the surest authority, we endeavour to trace it through ages and scenes unknown; and, instead of supposing that the beginning of our story was nearly of a piece with the sequel, we think ourselves warranted to reject every circumstance of our present condition and frame, as adventitious, and foreign to our nature. The progress of mankind, from a supposed state of animal sensibility, to the attainment of reason, to the use of language, and to the habit of society, has been accordingly painted with a force of imagination, and its steps have been marked with a boldness of invention, that would tempt us to admit, among the materials of history, the suggestions of fancy, and to receive, perhaps, as the model of our nature in its original state, some of the animals whose shape has the greatest resemblance to ours. [Footnote: _Rousseau_ sur l'origine de l'inegalité parmi les hommes.]