Sextus Empiricus and the radical promise of ancient skepticism — Sextus Empiricus (c. 200–250 AD), a Greek physician-philosopher of the Pyrrhonian school, developed a systematic form of skepticism that aimed not at nihilism or denial, but at tranquility through the suspension of dogmatic belief. Unlike other ancient philosophers who claimed to have found capital-T Truth—and whose rigid commitments often led to self-harm, social alienation, or absurd lifestyles—Sextus argued that peace of mind comes precisely from not claiming to have found it. His method was to oppose every philosophical argument with an equally compelling counterargument, producing a state of “equipollence” (equal weight on both sides), which he reported led, almost accidentally, to tranquility. This episode, featuring Cornell philosopher Tad Brennan, explores why Sextus attacked dogma, what he considered fair game for critique, how he induced equipollence, and whether his approach is ethically and epistemically sustainable.
Why Sextus Attacks Dogma
Philosophy as a source of self-inflicted suffering — Sextus observed that many ancient philosophers, despite seeking tranquility, ended up more disturbed than ordinary people because they treated their theories as unrevisable truths. Examples include:
A Pythagorean who bit off her tongue rather than eat beans.
Philosophers who killed themselves over unsolved logical puzzles (e.g., the Liar Paradox).
Stoics who claimed to feel “tranquil joy” while watching their children tortured.
Epicureans who replaced grief at a friend’s death with hedonistic calculus.
These cases illustrate how dogmatic commitment to a “Theory of Everything” leads to greater turmoil, not less—making philosophy itself a new source of unrest.
Epistemic caution as ethical safeguard — For Sextus, the primary issue with dogma is epistemic: claims to final truth are rash and premature. But this has ethical consequences—dogmatism breeds zealotry, intolerance, and extremism (ancient suicide over puzzles mirrors modern religious terrorism). He insists that if your beliefs justify extreme actions, you must be certain they’re right—and certainty is exactly what he denies is possible.
Sextus’s official stance: still searching — He formally distinguishes himself from both dogmatists (who claim to have found truth) and Academic skeptics (who claim truth is unknowable). He calls himself a “Pyrrhonian”—someone still actively searching. Every morning, he claims to wake up open to the possibility that today he’ll find the truth. Critics find this implausible given his consistent failure to find any view unassailable, but Sextus maintains this openness as a core part of his identity.
What Sextus Attacks: Dogma vs. Ordinary Belief
Dogma defined by how a belief is held, not its content — Sextus does not attack all beliefs, only those held dogmatically—that is, as unrevisable parts of a final, complete account of reality. Key markers of dogma include:
Systematicity: The belief is part of a grand, inferentially coherent system (e.g., Platonic Forms, Epicurean atoms).
Foundational status: It’s treated as a first principle or criterion of truth (e.g., sense perception as the basis of all knowledge).
Infallibility: It’s claimed to be certain, not probabilistic or provisional.
Unconventionality: It departs from everyday norms without sufficient justification.
Ordinary beliefs are exempt — A schoolchild who says “atoms exist” because their teacher said so is not a target; they offer no justification and hold no foundational commitment. But an Epicurean who builds an entire metaphysics on atoms is a target. Similarly, following religious customs (e.g., praying, attending festivals) is fine—but claiming to know the nature of God or the Trinity as ultimate truth invites skeptical attack.
The boundary is blurry and controversial — There’s no clean list of dogmatic vs. ordinary beliefs. The same proposition (e.g., “Jesus rose from the dead”) can be held dogmatically (by a theologian) or conventionally (by a pious layperson). Sextus likely targets the former. But this raises problems:
It’s unclear where everyday reasoning ends and philosophy begins (e.g., using supply-and-demand models pragmatically vs. claiming they reflect ultimate reality).
Ordinary life already involves implicit theorizing (e.g., inferring broccoli is in the vegetable bin), yet Sextus wants to reserve skepticism for professional philosophers.
Sextus offers no theory of ordinary belief formation — When asked how he forms everyday beliefs, Sextus refuses to theorize. He acts “like the grocery clerk”—responding to hunger, following customs, making inferences—without meta-level justification. He rejects the need for a criterion of truth in daily life.
How Sextus Attacks: The Method of Equipollence
Goal: induce equipollence (isostheneia) — Sextus aims not to prove opponents wrong, but to show that for every argument, there is an equally strong counterargument—so that belief is suspended, not reversed. This balance of credibility and incredibility leads, he reports, to tranquility.
Master arguments as universal tools — He employs several “master arguments” applicable to almost any claim:
The Agrippan Trilemma (Modes of Agrippa): Any justification either (1) regresses infinitely, (2) circles back on itself, or (3) rests on an unjustified “hypothesis.” Since all three are unsatisfactory, no belief can be fully justified. Sextus applies this to both a claim and its negation to produce symmetry.
Argument from future counterarguments: Even if no current counterargument exists, a future one might—so suspend judgment now.
Relativist and sensory doubt: Cultural variation (e.g., incest accepted in Egypt, condemned in Greece) and perceptual illusions undermine claims to objective truth.
Tailoring strength to the opponent — Sextus uses arguments of varying strength depending on how firmly someone holds a belief. Weak convictions get weak counters; strong ones get robust dialectical opposition. His goal is exact equivalence—not just confusion, but perfect balance.
He relies on his opponents’ logic — Sextus claims to have no commitments of his own. He uses logic (e.g., modus ponens, non-contradiction) only because his opponents do—he’s conducting an “immanent critique” from within their framework. Whether this is truly commitment-free is debated among scholars.
Equivalence ≠ aporia — Aporia is mere perplexity (“I don’t know what to think”). Equipollence is stronger: “Both sides are equally believable and unbelievable.” Sextus achieves this by running the same skeptical modes on both a proposition and its negation.
The Source and Limits of Tranquility
Tranquility as a byproduct of suspension — Sextus reports that after achieving equipollence across many domains, he unexpectedly found peace. He didn’t find truth—but he stopped needing it. Tranquility arose from the absence of dogmatic striving, not from resolution.
He returns to ordinary life—but wiser — Sextus ends up living conventionally: eating when hungry, following local customs, experiencing natural emotions. But unlike ordinary people, he’s free from the self-imposed disturbances of philosophical dogma. He still suffers life’s inevitable hardships (hunger, illness), but not the added turmoil of believing he must solve metaphysics to be happy.
Is this reproducible? — Sextus recommends this path to others (calling himself a “philanthropist”), implying it can work beyond his own case. But he offers no causal mechanism or algorithm—only a self-report. This creates tension: if it’s just personal experience, why expect it to generalize?
Ethical shortcomings — By deferring entirely to convention, Sextus lacks resources to critique societal injustices like slavery, which was conventional in his world. He cannot launch a systematic challenge to the status quo without a theory of justice—which he refuses to provide. This makes him a quietist on social issues.
The high bar for overriding convention — Sextus implies that deviating from convention requires a complete, anomaly-free system—a standard so high it protects the status quo by default. Critics argue this is unreasonable; piecemeal improvements (e.g., rejecting flat Earth based on navigation) shouldn’t require a full cosmology.
Pyrrhonian vs. Academic vs. Modern Skepticism
Pyrrhonism vs. Academic Skepticism — Sextus distinguishes himself from the Academics (like Cicero), who claimed “knowledge is impossible”—a negative dogma. But historically, the Academics may have been closer to Sextus than he admits: they often targeted specific Stoic epistemology, not knowledge per se, and later embraced “probabilism” (acting on what seems most persuasive without claiming certainty).
Descartes as a copycat — Renaissance rediscovery of Sextus deeply influenced Descartes. But Descartes used skepticism methodologically—to clear ground for certain knowledge (the cogito, God, science). Sextus, by contrast, never sought foundations or reconstruction. Descartes had little originality; Sextus did it first and better.
Modern appeal and psychological questions — The host admits using Sextan techniques to avoid commitment (e.g., balancing Christian miracles with Buddhist ones to stay uncommitted). This raises the question: is skepticism a philosophy for the lazy or non-committal? Brennan counters that Sextus was highly productive and rigorous—his skepticism demands constant inquiry, not laziness. Remaining in suspension can be harder than believing.
Final Tensions and Legacy
Convention is not monolithic — Sextus acknowledges competing conventions (e.g., Roman vs. Greek vs. Egyptian norms) and uses them against each other. But he still defaults to his own society’s norms when no clear counter-convention exists—raising questions about arbitrariness.
No normative resources for belief revision — In ordinary life, we revise beliefs based on evidence (e.g., trusting someone with a good track record). But Sextus refuses to say such revisions are justified—only that they happen. He offers no account of better or worse reasoning, only descriptions of psychological compulsion.
A system with deep flaws but enduring insight — Brennan acknowledges Sextus’s scheme has serious problems: quietism on justice, blurred boundaries, lack of normative guidance. Yet its core insight—that the relentless pursuit of capital-T Truth can be harmful, and that tranquility may lie in letting go—remains powerful and applicable today.
