Michel de Montaigne

Lord Michel Eyquem de Montaigne (February 28, 1533 – September 13, 1592) was one of the most influential writers of the French Renaissance, known for popularising the essay as a literary genre. His massive volume Essays contains, some of the most widely influential essays ever written. Montaigne had a direct influence on writers the world over, including René Descartes, Blaise Pascal, Jean-Jacques Rousseau, Ralph Waldo Emerson, Friedrich Nietzsche, Isaac Asimov, and perhaps even William Shakespeare.

The admonition to each of us to know ourself must be crucial, as this God of science and light had it affixed to the brow of his temple, as if it summed up the whole of what he had to advise us.
If the soul knew anything, it would first of all know itself.
If I study, it is for no other science than which deals with the knowledge of myself.