Chrysippus put it well: "As long as the future is uncertain, I stick with choices that help preserve what's natural. God gave me the ability to choose this way. But if I knew for certain I was destined to get sick, I would even move toward the sickness. Think about it — if your foot could think, it would step into mud when it needed to. Why do ears of corn grow? So they can dry out. And why do they dry out? So they can be harvested."
Chrysippus therefore said well, So long as future things are uncertain, I always cling to those which are more adapted to the conservation of that which is according to nature; for God himself has given me the faculty of such choice. But if I knew that it was fated (in the order of things) for me to be sick, I would even move towards it; for the foot also, if it had intelligence, would move to go into the mud. For why are ears of corn produced? Is it not that they may become dry? And do they not become dry that they may be reaped?