Who hasn’t heard the philosophical slogan “Know thyself”? The phrase has a long, long pedigree. It’s said to go back to that most ancient of ancient Greek philosophers, Thales of Miletus, who lived in sixth century BC, and Plato tells us that it was inscribed at the entrance to the famous temple of Apollo at Delphi. It’s still popular today, over 2500 years later.

Most people seem think that knowing themselves is a good idea, or at least say that that’s what they think. “Know thyself,” is uttered reverently—as though it’s self-evidently a wonderful goal. Didn’t Socrates say that the unexamined life isn’t worth living? Self-knowledge is supposed to liberate us, to make us happier, healthier, and more productive. Self-help books and psychotherapy mavens sing its praises as an existential panacea.

Obviously, a certain amount of self-knowledge is a good thing. For instance, knowing that I like sushi helps me to choose what to have for lunch. But this light-weight, pedestrian sort of self-knowledge doesn’t have the gravitas that seems to come with “know thyself.” “Know thyself” sounds deep—like a call to some great quest from which one emerges as a transformed and improved human being. Well, I’m going to throw some shade on this ancient adage by invoking a different Greek philosophical principle, this one adopted from Aristotle: “Everything in moderation.” Too much of anything is bad, and that includes self-knowledge.

I’m going to put self-knowledge on trial, and I’ll say up front that the case for the defence looks pretty thin. I’ll now call my witnesses for the prosecution.

First up is old Thales. It was the Roman writer Diogenes Laertius who said in his popular, gossipy book Lives of the Eminent Philosophers that it was Thales who put the “know thyself” meme into circulation. Diogenes lived six hundred years after Thales died, so there’s no telling how accurate his report is, but it’s worth noting that he also attributed another quip about self-knowledge to Thales—one that isn’t mentioned nearly as often as “know thyself.” Diogenes told his readers that Thales said that knowing yourself is the most difficult thing in life.

Wow. That’s quite a mouthful. Saying that is saying that no matter what difficulties you or anyone else has experienced in life, or whatever tasks, however gargantuan, you or anyone else has taken on, knowing yourself is even harder. It’s more difficult than enduring torture, winning Olympic gold, or formulating the theory of general relativity.

If Thales was right, then anyone pursuing self-knowledge is in for a lot of work, to put it mildly. So if you’re contemplating setting foot on the path to personal enlightenment, you might want to reconsider. And my next three witnesses make self-knowledge sound even more off-putting.

Your honour, I call Immanuel Kant to the stand….

Fast-forward to the 18th century, and we find Kant, who is regarded by some as the greatest philosopher of the Enlightenment, if not of all time, warning us that self-knowledge destroys mental health. He wrote dolefully about the “hard descent into the Hell of self-knowledge” that leads to “the gloomiest melancholia.” “Melancholia” was an old term for severe depression, so he’s basically saying that if you embark on the path to self-knowledge, then you’d better keep your bottle of Prozac handy.

If this isn’t bad enough, the testimony of our next witness is even is even more damaging to the case of the defence. For my next witness, I call Johann Wolfgang von Goethe to the stand.

Around the same time as Kant was warning us about self-knowledge damaging our mental health, another German heavy-hitter pushed the envelope even further. Goethe was a polymath—he was a scientist-poet-novelist-playwright-critic—and he’s regarded as one of the greatest intellects of his age. Goethe described “know thyself” as a con, because it presents people with an impossible demand. “The great duty ‘know thyself,’” he wrote, “which sounds so important, has always seemed to me suspect, like a trick of priests in secret conspiracy who would like to confuse man through unfulfillable demands and lead him away from his proper activity in the external world to a false interior contemplation.” And he confessed that he’d rather run away than know himself. How come?

My next witness, Mr. Mark Twain, gives us an answer: “Man, know thyself—& then thou wilt despise thyself, to a dead moral certainty” and my final witness, Twain’s contemporary, the philosopher Friedrich Nietzsche added “This digging into one’s self, this straight, violent descent into the pit of one’s being, is a painful and dangerous undertaking. A man who does it may easily take such hurt that no physician can heal him.”

At this point, if not before, council for the defense might utter, “Objection, your honor! This is all hearsay. These so-called expert witnesses are merely offering opinions, without a shred of evidence behind them.” And that’s just the opportunity I’d need for the coup de grace. I would be able to parade a long line of psychologists through the courtroom who could testify—quoting empirical studies—that self-deception and mental health go hand in hand, and that depressed people see themselves and others more realistically than more “together” people do.

This is all pretty damning. If these world-class thinkers are to be believed, self-knowledge sounds like something that we ought to try to steer clear of (or maybe not, since Goethe claimed it’s unachievable anyway). But it’s not yet time to rest my case, because there’s something that’s awfully unclear in these proceedings. We’ve been examining the pros and (mostly) cons of self-knowledge, without ever having clarified what self-knowledge is supposed to be. That will be the topic of next month’s blog.

Photo by Bill Oxford on Unsplash