Gnothi Seauton

Lucius Annaeus Seneca s.d. C.L.

Inscribed over the door of the Delphic shrine to Apollo was the phrase "Gnothi Seauton," know thyself. This little aphorism has inspired countless poetry, drama, and philosophy. It seems an essential idea for anyone seeking to pursue a good life. After all, how can I know what the good life is for me until I know, or at least have some idea of, my own nature?
I raise this point because I believe that I have gotten off to a false start in my discussions on Stoicism. I began from an assumption of nature, rather than establishing it. With that in mind, I begin anew...
When I seek to know anything, I should begin from its beginning with the question "what is it?" So in my own case, I should seek to know what I am. (Note that I say what, not who, for who is simply the form following the function of what) What I am is a man, like any other. What does it mean, then, to be a man or, rather, to be of the species "mankind"?
At the most basic level that I can see or feel, I am flesh and blood, bone and sinew, and breath. Among the three basic kingdoms, this places me among the animals. Very well, I am an animal. But I think I am something above the beasts of the field. This is not ego or vanity, I think, I hope, but rather some observable characteristic. So what, then, makes me different?
I walk upon two legs, but so do apes. I can build structures, altering my environment to suit my needs and desires. So, too, do beavers, badgers, and birds. It is certainly not mortality, for all things die. This is the oldest law. It might be law that distinguishes us: that I can create - or at least conceive of - a thing separate from myself to govern my action. But what is the source of the law, at least of human law? Instinct, which is common to all animals, is response to stimuli; and, although habits can be learned through instinct, it does not seem equal to the task of creating formal rules.
Call this capacity Reason, the ability to govern instinct, to govern the body, and to govern passion.
I, then, am these things: some flesh, some breath, and Reason to rule them all.