Man... knows only when he is ...

Man... knows only when he is satisfied and when he suffers, and only his sufferings and his satisfactions instruct him concerning himself, teach him what to seek and what to avoid. For the rest, man is a confused creature; he knows not whence he comes or whither he goes, he knows little of the world, and above all, he knows little of himself.
Man... knows only when he is satisfied and when he suffers, and only his sufferings and his satisfactions instruct him concerning himself, teach him what to seek and what to avoid. For the rest, man is a confused creature; he knows not whence he comes or whither he goes, he knows little of the world, and above all, he knows little of himself.

Quotes from the same author

Knowing is not enough; we must apply. Willing is not enough; we must do.
Just trust yourself, then you will know how to live.
The really unhappy person is the one who leaves undone what they can do, and starts doing what they don't understand; no wonder they come to grief.
What is not started today is never finished tomorrow.
A man sees in the world what he carries in his heart.