‘Know Thyself’ is Not Just Silly Advice: It’s Actively Dangerous

There is a phrase you are as likely to find in a serious philosophy text as you are in the wackiest self-help book: ‘Know thyself!’ The phrase has serious philosophical pedigree: by Socrates’ time, it was more or less received wisdom (apparently chiselled into the forecourt of the Temple of Apollo at Delphi) though a form of the phrase reaches back to Ancient Egypt. And ever since, the majority of philosophers have had something to say about it.