So, you want to be a critical thinker? Listen to Marcus Aurelius

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[image: Marcus Aurelius on horse, Vatican Museums, photo by the author; this is essay #254 in my Patreon/Medium series]

These days there is much talk about “critical thinking,” though it’s hard to pinpoint what is meant by this rather abused phrase. At the college level, for instance, almost every department claims to be teaching critical thinking, but arguably only philosophy and, with caveats, psychology programs actually do. That’s because critical thinking isn’t just the notion that we should think critically about X (where X can be any subject matter). Although of course we should. Rather, critical thinking is the idea that there are certain specific methods, attitudes, and practical bits of information that provides us with the tools for thinking critically about any X.

Critical thinking is often associated with the word “skepticism,” as in “my understanding of the facts and my practice of good reasoning lead me to be skeptical that we are being visited by aliens onboard of flying saucers.” Now, Skepticism with a capital S was, of course, an ancient Greco-Roman philosophy that held that human nature is either highly fallible or downright impossible. Radical Skeptics like Pyrrho of Elis thought that we should make no claims to knowledge whatsoever. More moderate Skeptics, like the Academic Carneades counseled to hold onto our opinions lightly, since we can never be sure they will not be overturned tomorrow. The Skeptics were not interested just in epistemology, but in practicing eudaimonia, a life worth living. For them, the recipe for a eudaimonic life was precisely not to get too attached to our opinions, which will help us maintain a state of ataraxia, or tranquillity of mind.

Modern skepticism traces back to two major figures of the 18th century: David Hume and Pierre-Simone de Laplace. Hume famously said that:

And Laplace echoed the sentiment:

This approach was recast in the context of critical studies of pseudoscience by Marcello Truzzi:

And made popular by Carl Sagan:

But the problems posed by the limits of human knowledge, the notion of expertise, and even the difference between science and pseudoscience were certainly not the exclusive prerogative of the Skeptics (or of their modern counterparts, the skeptics). In the Platonic dialogue known as the Charmides, for instance, Socrates wonders how to tell a real doctor from a quack, and his conclusion isn’t optimistic:

As it turns out, the Stoics also were very concerned with the field of epistemology, and were in fact in constant debate with the Skeptics about such matters. Zeno of Citium, the founder of Stoicism, articulated an interesting theory of degrees of human belief, which is summarized by Cicero:

So there are four degrees of belief, according to Zeno. The lowest is “perception,” which corresponds to instinctual and/or unreflective belief. A bit more sophisticated is “assent,” which refers to situations in which we have actually reflected on our beliefs and have either confirmed or denied them. Then there is a “kataleptic” impression, the sort of belief that is so strong that it is hard to deny, like walking outside in the middle of the day and thinking “it’s daytime.” Just try to deny that sort of impression and convince yourself that it is night. Lastly, we have true knowledge, the sort of belief that can be arrived at, according to the Stoics, only by sages or by a community of experts. In modern parlance, that’s scientific knowledge. (More on Stoic epistemology here.)

Surprisingly, perhaps, I think one of the Stoics who engaged most thoroughly in critical thinking is Marcus Aurelius, the emperor-philosopher. It’s not just that he was careful in examining his “impressions,” it’s that he displayed what I consider to be the right attitude toward both knowledge inquiries in general and other people’s (alleged) mistakes. An attitude that modern skeptics, and even scientists, could much benefit from. I’ll demonstrate what I mean by way of six pertinent quotes from the Meditations.

Why do we engage with people whose beliefs we think are misguided? So that we can feel smug at our intellectual superiority? Oftentimes it sure feels that way. But Marcus reminds us that the proper attitude we should cultivate is one of trying to be helpful to the human cosmopolis. Sometimes this will encompass openly criticizing other people’s opinions, because they may be dangerous or pernicious. At other times it will just mean to move on without feeling compelled to engage in every little instance were we think someone is mistaken.

Do not wait for Plato’s Republic was the ancient way of saying don’t aim at perfection. Act right here, right now, because this is where you can make a difference. Often we feel our efforts at engaging in critical discourse are not worth it because they fall on deaf years. But in fact we do make a difference, albeit a small one. And that difference matters. It is worth your effort if just one person moves away from an unfounded conspiracy theory, or embraces vaccination, or recognizes the reality of climate change.

If we want to persuade others we need to understand what they are saying and why. It’s too easy, and in fact downright lazy, to simply assume that other people are silly or ignorant and that we know best. Maybe we do, and maybe they are not sufficiently acquainted with the facts. Bu if we don’t even try to understand why they think what they think we are unlikely to be in a position to change their mind.

Nobody wants to be wrong. When someone is convinced of this or that notion it is because they think they are correct. If they are not, it is up to us to try to show them their mistake. Without getting angry, because that doesn’t help either them or us.

I often hear something along the lines of “I can’t believe that people say X.” What do you mean you cannot believe it? You have observed, time and again, that people say X, regardless of your opinion that X is irrational, unfounded, or whatever. You know there are plenty of people out there that subscribe to untenable notions, that don’t know what they are talking about, and so forth. Don’t be surprised, then. Just accept this as yet another aspect of reality with which you just have to contend.

Naturally, other people are not the only ones who can go wrong. We have been wrong as well, in the past; perhaps we are wrong now; and very likely we’ll be wrong again in the future. So let us dismount our high horse and resume walking amongst other mortal and fallible beings.

Finally, a bonus quote from Epictetus that should also be useful advice to all wannabe critical thinkers out there:

A conjunctive proposition takes the form of “p and q,” where p and q are individual, or atomic, propositions. For instance, let p = “it is day” and q = “it is raining.” The conjunctive p and q is “it is day, and it is raining.” That conjunctive is true if and only if both p and q are true. What Epictetus is saying is that if someone declares a true conjunctive to be false, for instance by saying that it’s day, but it is sunny (while in fact it is raining) then the problem is not with the proposition, but with whoever is making the mistake. Therefore we shouldn’t be offended when someone utters an untruth. The joke’s on him, so to speak. He is the one that is embarrassing himself in front of the epistemic gods.

So, if we want to be effective critical thinkers, we can take to heart what Marcus and Epictetus are telling us, which can be summarized as follows:

  • Your priority should be to be useful to humanity
  • Even if you make a small difference, it matters
  • Listen to others and try to understand them
  • Remember, other people too think they are right
  • Teach them or endure them without losing your patience
  • Don’t act surprised that there are irrational people out there
  • Remember that, on occasion, you too hold to irrational beliefs
  • The truth is not affected by people speaking falsehoods

Happy (critical) thinking!

Stoicism, ethics, and philosophy of science. Complete index, by subject, at

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