Sage: this word may not often be used in our time, but it is the most ancient word that has to do with knowledge. Until the end of the seventeenth century, also known as the enlightenment, sages were regarded as the people who possessed all kinds of knowledge about thought, science, and art. There are no longer sages of this kind in our day. Scientists today are only knowledgeable about one of more than 20 fundamental sciences (and often only a branch of a particular fundamental science), let alone possessing knowledge about art and philosophy in their entireties. There are a great many scientists who devote their lives to only a single subject. For example, a surgeon who studies thyroid surgery would likely tell you candidly that the knowledge he has about the trachea, which is adjacent to the thyroid, is less than that of a medical school freshman.