FAQ

The Argument Clinic is a conversational argument mapper, an interface for drawing argument maps through discussion. As you chat with one of three guides, your guide draws an argument map depicting your argument.

Choose the Mapper if you already have an argument, your own or someone else’s (e.g, from a paper, a book, or a lecture), and want to see its structure. Choose the Builder if you have a claim and want to work out your own argument for it. Choose the Skeptic if you’d like to find out what your belief really rests on and, if all goes well, suspend judgment about it.

These are the house rules: no medical advice, nothing dangerous, no hate, no atrocity denial.

Yes, and real people might read them for quality assurance and to improve the site. Feel free to use a fake name and don’t share anything private. If you hit a usage limit and request an invitation, the email you enter is saved and used to send you your unique entry code. Maps you save to the Library are public (see The Library).

You’ve probably hit an hourly or daily limit. Each session costs money to run, so there are limits on how much it can be used. Come back when advised, or request an invitation.

It doesn’t. If you’d have ideas that can help support the Argument Clinic so that it can be made more widely available, contact Angela Mendelovici.

An argument map is a graphical depiction of an argument. The conclusion is at the top, and the premises that support it are below it, with arrows linking statements to the statements they support. A premise can have premises of its own, so an argument map can have several levels.

Premises that work together (co-premises) need each other to provide the support they're supposed to provide. If you take one away, the others no longer provide the intended support. Premises that work on their own (independent premises) each support the conclusion on their own. On the map, the arrows of premises that work together join before they reach the statement they support; independent premises reach the statements they're supposed to support via independent arrows.

An implicit premise is a premise that's assumped but not explicitly stated. The guides help identify implicit premises.

Yes. Choose the Mapper, then “Someone else’s argument.” You can specify the argument's author if you like.

While you're mapping, the Mapper and Builder help you build your argument without scrutinizing it. But when you finish with the Builder, they offer to look your argument over for gaps, premises a critic would push on, and unclear wording, one point at a time. You decide what to change.

The Skeptic is a little bit different. They check your argument for holes as you go, provide counterarguments for your claims, and show you where your justification runs out, goes in a circle, or is seen to go on forever. That's as critical as it gets.

Press “I’m done”. Your guide sums up the argument and provides you with a PDF of your map and discussion. If you mapped your own argument with the Mapper, they offer to pass it along to the Builder to spot weaknesses and help make it stronger.

To make changes to your map, tell the guide what to change (“that last premise should say...”, “these two work together, not separately...”, “rephrase the conclusion as...”), and it redraws the map. You can also remove a statement with the × on its box or start over.

Ask the guide to help you decide. They will help you figure it out.

The Skeptic is a virtual Pyrrhonian skeptic modeled on Sextus Empiricus. Tell the Skeptic what you believe, and they argue until neither side is weightier. Then you suspend judgment, and tranquility follows. Allegedly.

You state a belief, and the Skeptic helps you map out why you believe it, one reason at a time, drawing your argument map as you go. Follow any line of reasoning far enough and it rests on a fundamental assumption, goes in a circle, or is seen to go on forever. Once every line has met one of these fates, the suspension of judgment is yours, absolutely free.

Reaching the suspension of judgment is winning.

Debating the Skeptic teaches you about the structure of arguments, epistemology, and Pyrrhonian skepticism, all while bringing you to a state of tranquility.

I first built Debate the Skeptic in 2007, as a philosophy grad student at Princeton: hundreds of hand-coded rules that mostly said "Yeah, but a famous Princeton philosopher believes that not-P. Why should I believe you?" until you gave up. There was no vibe coding back then, so it was intense, grueling labor and the results were mixed.

In 2026, I revived it with AI, and now I am finally tranquil.

The Skeptic is Sextus Empiricus, brought back to life by AI (Claude, by Anthropic). Its journals, conferences, and Princeton philosophers are made up.

Pyrrhonian practice of setting opposing considerations against each other until neither is weightier (PH I.8–10), resulting in the suspension of judgment, from which tranquility follows “as a shadow follows a body” (PH I.29).

No. When the Skeptic tells you that honey tastes bitter to someone with a fever or that a paper in the Journal of Applied Astrology holds the opposite view, they aren't arguing that you're wrong. They're raising a consideration against your belief to show that the question of whether your belief is true is open, and hence that your belief can't simply be taken for granted—it needs justification.

Because showing that the other side is wrong doesn't show that yours is right. The Skeptic wants to help you examine your reasons for holding your beliefs, not your reasons for rejecting others. Once you see that your justification cannot be sustained, you suspend judgment and become tranquil at last.

That's a claim too. Skeptics suspend judgment about it.

Honey appears sweet to them, too; they just suspend judgment on whether it is sweet (PH I.19–20). They live by appearances, nature, feelings, customs, and know-how (PH I.23–24).

The Skeptic does not dispute claims about appearances or definitions, but such claims do not support claims about how things are beyond appearances. Definitions are empty and only constrain how certain states of affairs are described, and appearances don't suggest anything about how things are beyond appearances without the help of further premises, which the Skeptic does dispute.

Skeptical claims work like laxatives, flushing themselves out along with everything else (PH I.206).

Ready-made arguments for suspending judgment. Some favorites to try on your friends:

• Disagreement: You say P; others say not-P. Who decides?
• Relativity: Honey tastes sweet to you, bitter to someone with a fever.
• Distance: The square tower looks round from far away.
• Regress: What supports that? And that? And that?
• Hypothesis: If you can just assume P, I can just assume not-P.
• Circularity: If P rests on Q and Q rests on P, nothing holds either one up.

Sextus collects them in sets: the Ten Modes of Aenesidemus, the Five Modes of Agrippa, and a few more (PH I.36–186).

• Pyrrho (c. 360–270 BCE): The namesake. Wrote nothing. Legend has it friends kept him from walking off cliffs.
• Timon (c. 325–235 BCE): Pyrrho’s student, who mocked other philosophers in verse.
• Aenesidemus (1st century BCE) and Agrippa (1st–2nd century CE): Traditionally credited with the Ten Modes and the Five Modes, respectively.
• Sextus Empiricus (c. 200 CE): A doctor, and our main source.

Debate the Skeptic is my best attempt at a charitable interpretation of the Pyrrhonian skeptic's method, one that presents it in its most defensible and powerful form.

There is much disagreement over how to best interpret Sextus Empiricus's writings. One important disagreement concerns the scope of the skeptical method. On the rustic reading (Burnyeat 1980), Pyrrhonian skeptics suspend judgment on everything, including everyday beliefs like that it’s raining or that the bakery opens at nine. On the urbane reading (Frede 1979), skeptics suspend judgment only on philosophical and scientific theories (the “dogmas”), not everyday beliefs. (The labels come from Barnes 1982. All three papers are collected in Burnyeat and Frede 1997.)

Debate the Skeptic interprets Sextus according to the rustic reading, largely because the modes apply just as well to everyday beliefs as to philosophical dogmas. For example, they apply just as well to a belief that the bakery opens at nine as to a belief in Platonic forms.

Another interpretive choice is to emphasize Agrippa's trilemma. Though Debate the Skeptic uses all modes, the Skeptic mainly tries to lead their interlocutor to Agrippa's trilemma: all lines of justification lead to regress, circularity, or undefended assumptions. The Skeptic prioritizes these modes because together they form the skeptic's most principled and powerful master argument, working on any line of justification.

Important interpretive decisions were also made in how to best handle claims about appearances, claims about definitions, and, relatedly, analytic claims. Though Sextus has much to say about appearances (PH I.19–24) and definitions (PH II.205–212), leading to many interpretive possibilities, I've decided to (I think charitably) understand claims about appearances to be claims about what we would now describe as conscious mental states and to understand claims about definitions and analytic claims to be empty. However, that the skeptic's acceptance of appearances really is an acceptance of a claim about appearances is contested (Burnyeat 1980; Burnyeat 1982; Frede 1979), and the category of analytic truths was not recognized by Sextus at all, at least not in anything like the contemporary sense. Still, I've chosen to treat appearances, definitions, and analytic claims in the ways that I do because I think this is the best way to capture, and embody in the Skeptic, a core Pyrrhonian insight: that claims about appearances and stipulations about how we use words cannot entail claims about how the world is beyond appearance.

Together, these interpretive choices present Pyrrhonian skepticism at its most formidable. Or so it appears to me.

The Library is a searchable, public collection of argument maps submitted by visitors. You can rate arguments and link arguments to each other and to texts that make or discuss them.

The map, the author of the argument (if provided), and which guide was used are automatically saved. You may optionally also choose to add your name and your website. Your conversation with the guide is not saved to the Library.

Yes. When you save a map, you’re given a private link for retracting it, which you should keep and not share it. If you’ve lost the link, write to us and we’ll remove it; if you gave your email address when you saved the map, we use it to confirm the submission came from you.

Yes. Maps in the Library are shared under a Creative Commons Attribution licence (CC BY 4.0): you may reuse them, even commercially, as long as you credit them, naming who saved the map (if they gave a name) and the Argument Clinic. You can use your own map however you like, whether or not you save it to the Library. If you share it, a mention of the Argument Clinic is appreciated.

The same argument can be mapped in more than one way, e.g., more or less charitably or in more or less detail. Under any map, click “Submit another version” to map the same argument again with the Mapper, the Builder, or the Skeptic. The versions are listed together under “More versions.”

Two maps can be linked as agreeing (they share statements or otherwise agree), opposing (their conclusions are negations of each other, one or more of their premises are, or they otherwise disagree), or otherwise related. For agreeing and opposing maps, you can also select which statements in one say the same thing as, or are negations of, statements in the other.

PhilPapers is the most comprehensive index of research in philosophy, so linking a map to PhilPapers entries connects the argument to the literature that states or discusses it. Arguments from other fields are welcome too: you can link to texts on any other website.

Click “Flag a problem” under the map.

No. Each visitor can rate a map once (rating it again changes the rating). As with usage limits, this uses a one-way scrambled code derived from your internet address, not the address itself.

• Joe Lau and Jonathan Chan, Critical Thinking Web: Argument Analysis. Free online tutorials, including argument mapping and hidden assumptions.
• Twardy, Argument Maps Improve Critical Thinking, Teaching Philosophy (2004).
• Harrell, Argument Diagramming and Critical Thinking in Introductory Philosophy, Higher Education Research & Development (2011).
• van Gelder, Using Argument Mapping to Improve Critical Thinking Skills, in The Palgrave Handbook of Critical Thinking in Higher Education (2015).

• Sextus Empiricus, Outlines of Scepticism, trans. Annas and Barnes. Start here.
• Mates, The Skeptic Way. Another translation, with commentary.
• Sextus Empiricus, How to Keep an Open Mind: An Ancient Guide to Thinking Like a Skeptic, trans. Bett. A short selection for general readers, with the Greek facing.
• Annas and Barnes, The Modes of Scepticism.
• Barnes, The Toils of Scepticism.
• Hankinson, The Sceptics.
• Bett (ed.), The Cambridge Companion to Ancient Scepticism.
• The Stanford Encyclopedia of Philosophy on Ancient Skepticism and Sextus Empiricus. Free and accurate (or maybe it isn't—who knows?).