Know thyself. —INSCRIPTION ON THE TEMPLE OF APOLLO AT DELPHI Self-knowledge is about knowing your own strengths and weaknesses. You must know what you can do and what you can’t; your powers and limitations, your strengths and vulnerabilities, what’s in your control and what isn’t. You know what you know, and what you don’t know. And you know, moreover, that you have cognitive blind spots—that there are things you don’t know, and you don’t know you don’t know them—what Donald Rumsfeld famously called “unknown unknowns.”
