Know Thyself!

The Prodigal Son: Pompeo Batoni

We would not be able to know which art would make oneself better if we did not know what we ourselves are. But is it perchance easy to know oneself; and was it a good-for-nothing he who put that inscription on the temple of Delphi; or rather is it a matter of something difficult and not within the reach of all? Whether it be easy or not, for us the question is put this way: knowing ourselves we will be able to know how we should take care of ourselves; while, if we ignore the former we shall not at all know the latter.

Plato, Alcibiades 1, 128 E - 129 A