Radical relativism denies absolute truth. But we can easily acquire the only possible truth (relative truth). According to Plato's Protagoras, you cannot fail to achieve it.

For radical skeptics knowledge is impossible, so achieving the truth seems to be a matter of luck.

Described this way, they seem polar opposites. But on the practical level, what difference does it make? An appeal to a shared, accessible truth is denied.

Why should we prefer one over the other?

Is it even possible for a proponent to answer this question?

I only know (fictitious) Protagoras' defense in Theaitetos. And though I don't find the general retorsion argument against relativism there works, I agree that Protagoras implicitly appeals to absolute knowledge the moment he describes his job as helping others to acquire more useful beliefs.

  • Just seems to be misphrased: "For radical skeptics [absolute] knowledge impossible, so achieving the [absolute] truth seems to be" ... impossible. Their perspective is an admixture, or superposition, of absolute truth and (inevitable) un-truth and so is no longer absolute truth. And that, for them, is the 'only possible' perspective/observational truth. A different type or order of truth might be acceptable, such as the truth of the existence of the raw sensory field before it is characterised and mischaracterised by observation and definition. Jan 11, 2023 at 20:39

1 Answer 1


I think what you might be getting at is the idea that relativism denies absolute truth and proposes a version of truth that is accessible to us, while skepticism denies knowledge and hence our access to truth while not questioning absolute truth.

I can see that it would be hard to accept both. However, both are thought to be in conflict with common sense and it is perfectly possible to reject both. It would certainly be possible to reject one and accept the other. But since one is a thesis about truth and the other about knowledge, the relationship between the two would depend on the details of each doctrine.

One couldn’t make a decision without first considering both separately and independently. It all depends on the arguments and on the details of the version of each that you are considering.

The objection that skepticism makes no difference on the practical level has been made from time to time. But most, if not all, philosophers who have written about it regard it as a heuristic exercise to test what we think we know; their project is to articulate it and then work out how to escape from it. Pyrrho and his school are often cited as a radical sceptics but I don’t know of any others. Relativism, however, is often thought to make a difference because it seems to allow the possibility that two contradictory statements might be true at the same time. This is worrying for scientists and particularly disturbing in the case of moral relativism.

By the way, Plato’s interpretation of Protagoras in the Theaetetus is not regarded as accurate. What Protagoras actually says is “Man is the measure of all things” which does not suggest a subjectivist doctrine. The subjectivist interpretation is suggested later on by Aristotle and Sextus Empiricus. Protagoras’ slogan suggest a kind of relativism closer to modern versions which are, to put it this way, intersubjective i.e. shared. I’m not even sure that it is relativist in the modern sense. See Protagoras (Stanford Encyclopedia of Philosophy).

  • By the way, Plato’s interpretation of Protagoras in the Theaetetus is not regarded as accurate. edited it to "Plato's Protagoras"
    – viuser
    Jan 11, 2023 at 20:15
  • @viuser That's better. Sorry to seem pedantic, but the difference is great enough to pay attention to. I hope the rest is somewhat helpful.
    – Ludwig V
    Jan 11, 2023 at 21:13
  • Yes, it was helpful. IMHO skepticism is a serious and problematic as relativism. I didn't claim that skepticism makes no difference on a practical level. If doubt is real, not just pretension at least. I meant that skepticism and relativism are very different but seem to result in the same practical, social problems. It's like the horseshoe theory of epistemology (funny, I don't believe in the political horseshoe theory, though). Most interesting would be a relativist vs. skeptic debate.
    – viuser
    Jan 12, 2023 at 0:52
  • @viuser. Glad it was helpful. The question whether sceptical doubts are real is a real one. For a discussion of "making no difference" see Hume, Enquiry, Section 12, part II "The great subverter of Pyrrhonism or the excessive principles of scepticism is action, and employment, and the occupations of common life" etc.
    – Ludwig V
    Jan 12, 2023 at 10:40

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