“The universe,” wrote astrophysicist Neil DeGrasse Tyson, “is under no obligation to make sense to you,”¹ and, for the most part, it doesn’t, to anyone. Beyond the incomprehensibility of quantum mechanics—and our inability to reconcile the main branches of physics—we’ve only managed to discover, after 500 years of groping in the dark, a meager 5 percent of the observable universe. The other 95 percent, physicists tell us, is composed of imperceptible dark matter and dark energy,² surmised to exist based only on its impact on the small sliver of reality that has managed to sift its way through our pitiable and corruptible senses. 

For an ancient skeptic like Sextus Empiricus, basing grand proclamations about the ultimate nature of the universe—including the existence or nonexistence of God—on this shaky and incomplete foundation is unjustifiable and, frankly, utterly foolish. Isn’t it clear, Sextus would tell us, that we’re all, for want of a better phrase, full of shit?

Perhaps fittingly, we know very little about Sextus Empiricus, other than that he was a doctor and philosophical skeptic living sometime in the second or third century CE somewhere (probably) in the Roman world. We know him primarily through his three surviving works, the most important of which, for our purposes, is Outlines of Pyrrhonism, which describes the brand of skepticism established by Pyrrho of Elis (c. 360 – c. 270 BCE), of which no works survive. 

Sextus is therefore our best source on ancient Pyrrhonism, a rather radical form of skepticism that calls for the near-universal suspension of judgment on all (or most) matters. The idea is that, for any proposed dogma, a competing dogma, of equal strength, can be established; it therefore makes sense to suspend judgment, adopting no definitive position, and, in doing so, to achieve tranquility and peace of mind. As Sextus wrote:

For the person who has the opinion that anything is by nature good or bad is disturbed all the time. When the things thought to be good are not available to him, he believes he is being persecuted by things that are by nature bad, and he pursues those that (as he thinks) are good; but upon getting these, he falls into even more disturbance, both because of being excited beyond reason and measure, and because, fearing a change, he does everything in order not to lose the things he thinks are good. But the person who is indefinite about things good or bad in their nature neither flees nor pursues anything intensely, and for this reason has tranquility.³

There’s no doubt that having an open mind is a good thing—and something the world needs more of—and that you should fully consider the counterarguments to even your dearest beliefs, but Sextus’s prescription for total tranquility comes at far too steep a price. We’ve learned too much, scientifically, to really believe that every dogma we have has a counterargument of equivalent strength. This is just not correct, or useful, and there are better approaches to the acquisition of knowledge (critical rationalism⁴ and Bayesian reasoning,⁵ for example, both take into account probabilities and degrees of belief). 

But let’s not so quickly and completely dismiss him; in fact, Sextus has much to teach us. His brand of skepticism—while perhaps overreaching in certain areas—is highly relevant to metaphysics, to religion, to God, or to any domain of knowledge that seeks to move beyond our direct and immediate confrontation with the world. It is in these areas that Sextus’s greatest, lasting contributions to posterity reside. 

Our immediate aim in this article, then, is to see why Sextus thinks we should suspend judgment on the question of God’s existence. But before we get to that, it’s instructive to examine our cognitive limitations a bit further.  

The Limitations of Human Perception

Sextus was, justifiably, very suspicious of the senses. While we must rely on them to live out our daily lives and navigate our environment—as is the case with any other animal—the corruptible and changeable nature of our senses precludes our ability to ever get to the bottom of how reality “actually is.” 

Sextus used several examples to demonstrate the point. “Honey,” Sextus wrote, “appears to us to sweeten; we agree to this, for as a matter of sense-perception, we are sweetened. But whether it is indeed sweet as far as argument is concerned, we investigate—which is not the apparent thing but something said about the apparent thing.”⁶

You may recall a similar quote from Democritus: “Sweet exists by convention, bitter by convention, colour by convention; atoms and Void (alone) exist in reality.”⁷

Sextus would agree with all of this, except the last part about atoms and the void. It is enough to say that honey tastes sweet to us; as to what, at bottom, honey actually is—its fundamental properties—we can never know (even with scientific instruments), because we can only experience it through our perceptual filters. We are, quite literally, prisoners inside the dark caverns of our own skulls. 

Let’s press this point a bit further with a simple question: What is the true color of, let’s say, a Golden Delicious apple? 

You might reply that it is golden-yellow, but the skeptic would remind you that a Golden Delicious apple, before it ripens, is green, and, if overripened, is brown. Alternatively, to someone with total colorblindness, the apple appears as a shade of gray. Different animals—with different numbers of color receptors (cones)—may see the apple in different shades of yellow, or as some other color, like gray or tan. And someone in the throes of mental illness or intoxication, or someone who is dreaming, may hallucinate the apple as, let’s say, pink. 

So, the skeptic would ask, is the apple really yellow, green, brown, gray, tan, all of the above, or none of the above? And whose perspective do we prioritize? If you see the apple as yellow, and someone else perceives it as gray, since you are a party in the dispute, you are automatically disqualified from being a judge, since a judge must have an outside, objective perspective. But in fact, there is no outside, objective perspective, but only, inevitably, your own. 

All you can really say, then, is that the apple appears, in this particular moment, to you, as the color yellow. But unless you think your perspective should represent the standard by which all other perceptions in the universe should be judged, you cannot state, conclusively, that the true color of the object you’re calling a “Golden Delicious apple” is the one true color—yellow—that is “inherent” in the object. 

Since the color of the apple changes based on who is looking at it, the circumstances in which they’re viewing it, their current cognitive state, the number and types of cones in their eyes, the ambient light, and the ripeness of the fruit, it seems obvious, to the skeptic, that the color of the apple is not inherent in the apple but constructed by the mind of the perceiver (and this applies equally to all of the apple’s other qualities). And since the perceiver actively constructs the color, which differs from other observers, they cannot ever get to the object itself to “see” how it really is. This, of course, anticipates both Immanuel Kant and Rene Descartes, who might just as well have said, “I perceive, therefore I am.” 

In fact, when Descartes claimed he could doubt the legitimacy of everything other than his own ability to think (and therefore exist), Sextus wouldn’t have thought this was anything particularly interesting or novel. But whereas Descartes would proceed to use the “self-evident” existence of God as grounds for believing in the veracity of his perceptions, Sextus would simply take the doubt on its own terms as justification to forever suspend judgment. 

In response to Descartes’ demon—the idea that an evil demon is tricking us by manipulating everything we experience⁸—Sextus would shrug his shoulders. Perhaps we are all being manipulated by the demon, or perhaps we’re not. But in any case, this question shouldn’t bother us, because it’s not worth taking a position on. Daily life remains unchanged.  

Returning to the apple, you might be waiting to reply that its true color is defined by wavelengths of light, which correspond to the color golden-yellow. But it’s important to note that this doesn’t avoid the problem. The issue at hand is the differing perceptions of wavelengths of light, and even something like a “wavelength” itself, as a scientific concept, is something that is perceived from a particular perspective, using particular senses and a particular brain. To universalize something inherent to our own minds—or that is a product of our minds—is, to the skeptic, a grievous error. 

So it turns out that we can’t even conclusively determine the color of an apple; how then, Sextus would ask, are we justified in proclaiming knowledge about the creator of the entire universe?!  

The Skeptic’s View on the Existence of God

“Since not everything that is conceived also shares in reality,” Sextus wrote, “but something can be conceived but not be real, like a Centaur or Scylla, it will be necessary after our investigation of the conception of the gods to inquire also into their reality.”⁹ 

This somewhat obvious point is a good place to start. After all, it’s not difficult to invent stories about gods—which probably accounts for the fact that humanity has invented hundreds or thousands of them—but it is an altogether different task to demonstrate, to the satisfaction of a skeptical mind, their actual existence. Let’s see what Sextus has to say about this. 

Sextus’s first argument for suspending judgment on God’s existence is that agreement on God’s nature cannot even be established, and so we don’t even know what, exactly, we’re arguing exists. As Sextus wrote:

Well, since some of the dogmatists say that god is a body, others that he is incorporeal; and some that he is human in form, others not; and some that he is in a place, others not; and of those who say he is in a place, some say this is within the universe, some outside it; how are we going to be able to gain a conception of god, if we don’t have any agreement on his being, or his form, or a place he occupies?¹⁰

In fact, if god didn’t exist, this sort of disagreement would be exactly what one would expect. All the various opinions and disagreements are ample evidence of our ignorance, not divine knowledge (as Cicero had claimed). And, in any case, as Sextus had previously insisted, you can always (1) take one position (e.g., that God is corporeal), (2) contrast it with its opposite (e.g., that God is incorporeal), (3) note their equal likelihood, and then (4) suspend judgment and move on with your day. 

But let’s say, for the sake of argument, that you insisted that the answer is obvious: God is incorporeal, imperishable, and blessed. Well, you’d still need to define what blessed means, which, as Sextus noted, philosophers also cannot seem to agree on. “They should tell us,” Sextus insisted, “what ‘blessed’ is—is it what acts according to virtue and shows providence toward those things ranked below it,” as the Stoics maintained, “or is it what is inactive and neither has any trouble itself nor produces any for others,”¹¹ as the Epicureans maintained? 

Here again we have opposing dogmas, of equal plausibility, compelling us to, once again, suspend judgment. 

But we can keep going (although this can get tedious quickly). Let’s say you want to argue that God is incorporeal and blessed in that God “acts according to virtue and shows providence” toward his creation. The skeptic will ask, by what method do you propose to demonstrate this? 

If you say it is revealed in sacred texts, you must provide proof as to the reliability of those texts, which will require an additional criterion of truth, which will require further proof, ad infinitum. This is the famous “problem of the criterion” that Sextus introduced:

For the proof always requires a criterion to confirm it, and the criterion also a proof to demonstrate its truth; and neither can a proof be sound without the previous existence of a true criterion nor can the criterion be true without the previous confirmation of the proof.¹²

This leads to an infinite regress of justifications or, more commonly, to circular reasoning, such as that the Bible is the word of God because the Bible says it is the word of God, or that God’s existence is proven via reason, and reason is validated by God. Of course, one can avoid the problem by simply asserting things without justification at all, as in “God exists because I have ‘faith’ that he does,” but this is not going to be persuasive to anyone who doesn’t already share your assumptions. 

The skeptic trains his mind to avoid making silly assertions like these, as they are never provable, and therefore represent sources of mental distress. In fact, the more dogmatic you are, the more you are always on guard against anything that may contradict your beloved beliefs. The skeptic avoids this agitation by simply suspending judgment. How many needless fights over imaginary things, one wonders, would be avoided if we all adopted this attitude?

Finally, it’s worth noting that we find in Sextus’s writings—following Epicurus—an explicit formulation of the problem of evil. The argument goes like this: If God has providence over everything, and there is evil in the world, then that means that God either created evil or permits evil to exist. And if God has providence over some things and not others, then God is limited in either power or in love. 

This means that any positive assertions made about God are, in some way, impious. As Sextus wrote:

From these points we reckon that those who say with full commitment that there is a god are probably forced into impiety. If they say that he has providence for everything, they will be saying that god is a cause of bad things, while if they say that he has providence for just some things, or even for nothing, they will be forced to say that god is either malicious or weak—and people who say these things are quite clearly impious.¹³

This is a powerful statement, and a very good reason to suspend judgment even if you tend towards religious sentiments. If you insist that God exists, you are either implicating God in evil, or else asserting that God is weak, immoral, or both. You’d be much better off, according to Sextus, suspending all judgment entirely. 

There’s Probably No God. Now Stop Worrying and Enjoy Your Life.

In 2009, the organization Humanists UK launched an Atheist Bus Campaign that ran an advertisement on buses across the UK, which read, “There’s probably no God. Now stop worrying and enjoy your life.”¹⁴ The ad campaign was a response to Christian ads, also displayed on buses across the UK, that included a link to a website that graciously informed non-Christians that they would burn in hell for all eternity (a nice expression of universal love that Christians like to talk about). 

I think Sextus would ultimately approve of this atheist campaign. He may have worded it a bit differently, maybe something like, “Suspend judgment on God’s existence. Now stop worrying and enjoy your life.” But the overall sentiment would be the same. Sextus would agree that dogmatic pronouncements on topics that are fundamentally unprovable—and subject to strong disagreement—are only sources of reliable mental distress. We would all be better off—and a lot more tranquil—if, when asked if God exists, simply said, “I don’t know—and neither do you.” 

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Christians, of course, are a lot more confident in their knowledge of God’s existence. This unwavering faith comes, above all, from their sacred scripture—a Christian’s most prized (and vulnerable) possession. Atheists will also come to cherish this holy scripture, but for very different reasons indeed. 

It turns out that the Bible’s inconsistencies and absurdities practically make the nonbeliever’s case for them, and it was Porphyry of Tyre—the true initiator of serious biblical criticism—who was the first to realize this. Let’s see what he discovered.  

Notes

1. Neil deGrasse Tyson, Astrophysics for People in a Hurry (New York: W. W. Norton, 2017), 13.
2. European Space Agency, “The Dark Universe,” ESA Science & Exploration, https://www.esa.int/Science_Exploration/Space_Science/Euclid/The_dark_Universe, accessed February 25, 2026.
3. Sextus Empiricus, How to Keep an Open Mind: An Ancient Guide to Thinking Like a Skeptic, trans. Richard Bett (Princeton, NJ: Princeton University Press, 2021), 27.
4. John R. Wettersten, “Karl Popper: Critical Rationalism,” Internet Encyclopedia of Philosophy, https://iep.utm.edu/karl-popper-critical-ratiotionalism/, accessed February 25, 2026.
5. Hanti Lin, “Bayesian Epistemology,” Stanford Encyclopedia of Philosophy, https://plato.stanford.edu/entries/epistemology-bayesian/, first published June 13, 2022.
6. Sextus Empiricus, How to Keep an Open Mind, 21.
7. Kathleen Freeman, Ancilla to the Pre-Socratic Philosophers: A Complete Translation of the Fragments in Diels, Fragmente der Vorsokratiker (Cambridge, MA: Harvard University Press, 1983) DK 68 B9. 
8. René Descartes, Meditations on First Philosophy, trans. John Cottingham (Cambridge: Cambridge University Press, 1996).
9. Sextus Empiricus, How to Keep an Open Mind, 167.
10. Sextus Empiricus, How to Keep an Open Mind, 153.
11. Sextus Empiricus, How to Keep an Open Mind, 155.
12. Sextus Empiricus, Outlines of Pyrrhonism, trans. R. G. Bury, Great Books in Philosophy (Amherst, NY: Prometheus Books, 1990), 50.
13. Sextus Empiricus, How to Keep an Open Mind, 165.
14. Humanists UK, “Atheist Bus Campaign,” Humanists UK, https://humanists.uk/campaigns/successful-campaigns/atheist-bus-campaign/, accessed February 25, 2026.

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