I have been at Delphi twice already, and I plan on going back again. It is a truly magical place. No, I don’t believe in “magic,” I’m talking about real magic, the sense of awe that strikes you when you arrive there. Despite the tourist shops, the bed and breakfasts, and the restaurants, you cannot avoid been struck by the sheer beauty of the place: a green mountainous peak overlooking a deep valley, from where you can see the Aegean Sea in the distance. No wonder the ancients thought it a place privileged by the gods, as testified today by the beautiful ruins of the temples of Apollo and Athena.

It is in Delphi, of course, that the most famous Oracle of the ancient world resided. Still today you can see the omphalos (i.e., navel), the stone that allowed direct communication between the priestess and the gods. Modern science has suggested that the location is characterized by significant underground quantities of ethylene or methane, which may cause hallucinations to people exposed to them. So far, however, this is speculation, and not really germane to the psychological power of the Oracle. The advice given by the priestess of Apollo, regardless of its natural trigger, was often sound, if not necessarily amenable to an immediate interpretation.

One of my favorite stories is that of Themistocles, the Athenian general who was told that Athens will successfully defend itself from the powerful army of the Persian king Xerxes by building a wall of wood (“Though all else shall be taken, Zeus, the all seeing, grants that the wooden wall only shall not fail”). The notion, of course, is ridiculous on its face. Surely the mighty Persians would not be stopped in their tracks by mere wood. But interpret the advice more creatively, as Themistocles did, and you realize that the wood in question was that of the ships forming the formidable Athenian navy, which did, in fact, annihilate the opponent fleet at the battle of Salamis.

Delphi was also famous for a list of “commandments” that were allegedly assembled from the wisdom of the Seven Sages, a legendary group of philosophers, statesmen, and law-givers from the early history of Greece. Perhaps the most famous of such commandments was “know thyself,” which has since inspired countless philosophers, most famously informing Socrates’ entire career as a gadfly to the good people of Athens (who repaid him for his trouble, as we know, by putting him to death by hemlock).

Now an article published in Aeon magazine by Bence Nanay (a professor of philosophy at the University of Antwerp, Belgium) tells us not only that “know thyself” is “silly” advice, but that it’s actively dangerous. While Nanay has a point, I will argue that it is his own article that is, in fact, dangerous.

Nanay tells us that the Delphic injunction is based on an untenable picture of the self, and of how we make decisions — though I wonder how he knows which theory of mind and psychological agency was endorsed by whoever chiseled the famous phrase on the entrance to the temple of Apollo.

He invites us to consider a simple situation: “You go to the local cafe and order an espresso. Why? Just a momentary whim? Trying something new? Maybe you know that the owner is Italian and she would judge you if you ordered a cappuccino after 11am? Or are you just an espresso kind of person? I suspect that the last of these options best reflects your choices. You do much of what you do because you think it meshes with the kind of person you think you are. You order eggs Benedict because you’re an eggs Benedict kind of person. It’s part of who you are. And this goes for many of our daily choices.”

The notion is that we have somewhat stable ideas about who we are, which is practically useful, since it saves us a lot of time whenever we have to make decisions. Except if you go to Starbucks, because they have far too many choices. Then again, no self respecting Italian would go to Starbucks. Or order a cappuccino after 11am. (See what I did there? I have an image of myself as a self respecting Italian, hence my choices about where to get my coffee and when it is proper to order a cappuccino. Also, no Parmesan cheese on seafood pasta, please.)

But of course, as Nanay reminds his readers, we also change, all the time. On occasion these changes are sudden and dramatic, and therefore very noticeable. Many people feel and act differently after having had a child, for instance. Or having experienced a trauma, such as a diagnosis of cancer. Many changes, though, are subtle and slow, yet cumulative over time. It is this second kind of change that creates the major problem for the Delphic injunction, apparently: “The problem is this: if we change while our self-image remains the same, then there will be a deep abyss between who we are and who we think we are. And this leads to conflict.”

Not only that. We apparently suffer from what psychologists call the “end of history illusion,” the idea that, right now, we are final, finished products. This, and not our selves of five, ten, or twenty years ago, is who we really are, and who we will keep being until our demise. The end of history illusion is, of course, nonsense. We are never finished, as the only constant throughout our life is precisely that things, including ourselves, change. You can see why Nanay is worried.

The problem concerns much more than your choices of morning java: “Maybe you used to genuinely enjoy doing philosophy, but you no longer do. But as being a philosopher is such a stable feature of your self-image, you keep doing it. There is a huge difference between what you like and what you do. What you do is dictated not by what you like, but by what kind of person you think you are.”

In an interesting twist, Nanay even manages to blame our addiction to social media on this alleged incongruence between who we are and who we think we are. That incongruence not only wastes a lot of our time and efforts (because, robotically, we keep doing things we no longer enjoy or think important), it also generates a fair degree of cognitive dissonance between reality and our image of reality. And cognitive dissonance, again the psychologists helpfully remind us, is emotionally costly. “Hiding a gaping contradiction between what we like and what we do takes significant mental effort and this leaves little energy to do anything else. And if you have little mental energy left, it is so much more difficult to switch off the TV or to resist spending half an hour looking at Facebook or Instagram.” Now you tell me!

Nanay concludes that “If we take the importance of change in our lives seriously, [following the Oracle] just isn’t an option. You might be able to know what you think of yourself in this moment. But what you think of yourself is very different from who you are and what you actually like. And in a couple of days or weeks, all of this might change anyway.” He then concludes with a pseudo-profound piece of poetry from André Gide, who wrote in Autumn Leaves (1950): “A caterpillar who seeks to know himself would never become a butterfly.”

Right. Then again, caterpillars are too stupid to philosophize about themselves, not to mention that their are profoundly ignorant of their own biology. And does anyone really believe that, except (maybe) for traumatic experiences, we can change a lot in mere days or weeks?

I hope it is clear what the central flow in Nanay’s argument is: he is assuming an essentialist view of the self, the self conceived as the “true,” unchanging part of who we are, which people are supposed to “discover” in order to live authentic lives. I’m sure some Ancient Greeks did hold to a similar notion (Plato comes to mind), though they were usually far too good observers of human psychology to fall into that trap. It is not at all clear whether whoever came up with the Delphic injunction subscribed to such an untenable theory of the self. What is abundantly clear is that “know thyself” is very good advice regardless, indeed even more so if our selves are dynamic bundles of perceptions, sensations, desires, and deliberations, to paraphrase and build on David Hume.

Let’s consider the more serious of Nanay’s examples, that of the philosopher who doesn’t realize that he doesn’t believe in philosophizing anymore. I don’t know whether that example was autobiographic, but I can certainly counter it with an autobiographical anecdote of my own. Ever since I can remember I wanted to be a scientist, a dream that eventually came through when I was appointed assistant professor of botany and evolutionary biology at the University of Tennessee in Knoxville, back in the distant 1995.

I had a reasonably successful career for several years in my chosen field of specialization, gene-environment interactions, rising through the ranks of associate and then full professor with tenure. My self image had been one of a scientist since I was five or six years old, and it had served me well until my late thirties and early forties.

Then a midlife crisis ensued, partly precisely because my reflections about myself began to alert me of some sort of growing gap between my mental image of me and how I was feeling while doing what I was doing. I realized that I was less and less interested in laboratory and field research, and more and more in theoretical and conceptual issues. And the step from the latter to philosophy of science wasn’t very big. Partly because such conscious reflections (the “know thyself” part), and partly because of serendipitous events, I was able to enroll as a graduate student in philosophy, publish a book and several papers in the field, and eventually switch career and become a full time philosopher.

That’s where I am now, though other adjustments have occurred in the meantime, like my increased interest in public philosophy, and my novel interest in Stoicism. These changes, too, were made actionable by the fact that I have a habit of reflecting about my feelings and experiences, trying as much as possible to keep adjusting what I actually do and what I want to do, in a never ending exercise of reflective equilibrium.

The bottom line is that my life, I can confidently assert, has been made better and better by trying to follow the Delphic commandment. I suspect the same is true of other people, who can benefit from a monitoring of the evolving “self,” coupled with the occasional redirection and adjustment of what they do or pursue. Contra Nanay, it is this process of self knowledge that reduces, or even preempts, the cognitive dissonance he refers to. And, apparently, it will also save you a lot of wasted time on Facebook and Instagram.

What is truly dangerous is not to follow the not at all “silly” advice that has served Socrates and so many others since. You may end up mispending a good chunk of your life if you ignore it. And if you have the chance, go to Delphi. You’ll thank me for it.