When Socrates, an Athenian moral philosopher, cautioned “man know thyself” most scholars were inclined to have construed it from a banal perspective.

Who invented the phrase know thyself?

In Plato's Phaedrus, Socrates uses the maxim "know thyself" as his explanation to Phaedrus to explain why he has no time for the attempts to rationally explain mythology or other far flung topics.

Which philosopher said we should know thyself?

Know thyself: a moral epistemological and injunction

The philosophy of Socrates still shines today. Even the most distant philosophers of his principles have discussed and debated his philosophy and teaching (Nietzsche for example). The phrase “Know thyself” has not been invented by Socrates.