There isn’t one. At least one that you have a say in. Your purpose is to be a part of nature as you always have and always will be. Your purpose right now is to conduct yourself as you are, since that’s how nature made you to be. You will die, as nature has purposed. You will be re-used as nature has purposed. You will never again be in the natural state you are currently in, but you will always be a part of nature.

Reflect frequently upon the instability of things, and how very fast the scenes of nature are shifted. Matter is in perpetual flux. Change is always and everywhere at work; it strikes through causes and effects, and leaves nothing fixed and permanent.

The only constant is nature. If it has a purpose, you have found yours.