The only thing constant is change
We circle in the night and we are devoured by fire.
The nature of things is in the habit of concealing itself.
Knowing many things doesn't teach insight.
It is by disease that health is pleasant; by evil that good is pleasant; by hunger, satiety; by weariness, rest.
No man ever steps in the same river twice, for it's not the same river and he's not the same man.