The Yncas had attained very little knowledge in astronomy and natural philosophy, for, not being acquainted with letters, although there were men of considerable talent among them, whom they called Amautas, who conceived philosophical subtleties such as were taught among that people, yet, being unable to write and thus hand down their learning to their successors, their discoveries perished with them, and thus they made little progress in all sciences, and were without any knowledge in some, only possessing general principles drawn from the light of nature, and even these were denoted by gross and unpolished symbols, that the people might see and take note of them. We will give an account of what they knew on each subject. Moral philosophy was well understood, and it was left written in their laws, mode of life, and customs, as we shall see in the course of this history. They were aided in their knowledge by the natural law which they desired to observe, and by the experience they acquired in the practice of good customs, which were cultivated from day to day in their commonwealth.

But they knew little or nothing of natural philosophy; for, leading a simple and natural life, they had no need for making researches, or for snatching the secrets from nature. They passed them by without examination or knowledge, and thus had no necessity for investigating them, nor for studying the qualities of the elements.