“One species of knowledge does not differ from another in being ‘two-footed.’”
Aristotle, Kategorai (1B19)
While Xenophon is both detailed and systematic he applies his rigor to practical tasks, Tekne. Aristotle takes Xenophon’s self-help manuals to the next level by applying them to our most basic tools of understanding and communication—our use of language itself. His Kategorai provide detailed and elaborate descriptions of the seemingly obvious. But this nomenclature of the commonplace has a clear purpose. He frees us from the paradox and sophistry of the previous generations of Greek philosophers and allows for a more clear and rigorous rapprochement to Physis, an understanding of the natural world. This understanding was so useful that Kant would appropriate these same Categories, almost unchanged, as an important part of his Critique of Pure Reason more than two thousand years later. Which leads one to wonder—do these ideas seem to be obvious because they truly are self-evident to everyone always, or is it merely because we have accepted them as part our culture for such a long time?