Reflecting on Descartes's evil genius, I came up with an argument to use against his radical skepticism, that is, when he doubts even the basic laws of logic and basic mathematics (3 + 2 = 5). The argument goes like this:

If I claim that the basic laws of logic and mathematics are false, then the argument of radical doubt becomes insignificant because I have relied on the basic laws of logic to create the argument of radical doubt itself . In summary: if the basic laws of logic are false, my own doubting loses its meaning as I began to doubt starting from logical arguments.

However, I found possible counter-arguments to my own argument:

  1. once we have established that the laws of logic are not valid, it is not even possible to formulate a real argument against since their invalidity has been affirmed.

  2. if the evil genius is part of a world that is absolutely other to me, totally incomprehensible to me from any point of view, how can I be sure that the argument I use is valid in its world which precisely follows other logical laws (or maybe, it doesn't even have laws as we understand them).

  3. the evil genius created the world that I perceive (illusory), but it is not subject to the laws of the world that he himself created (a sort of almighty Christian God), indeed it is not subject to any law of any kind and therefore is totally omnipotent and therefore can somehow deceive me.

Final thought: Even if a question should come naturally to the deceived, why him? Since the world he perceives does not seem to be centered on him in any way. One could argue that maybe there is some reason not known to him or in the worst case totally incomprehensible, which makes this scenario of total deception (solipsistic among other things, because only he exists) plausible.

What do you think about the argument against radical skepticism, the loopholes I thought and the final thought?

  • Academic vs. Pyrrhonian skepticism is worth considering, here. The skeptic who asserts their standpoint will face logical troubles such as you've described; the skeptic who merely floats perpetually in an inquisitive state, might not. Now, whether anyone credibly every does float about as such, is also open to question, and if the move is made from inquiry to at least, "It is possible that I am always deceived," we can turn the assertive skepticism against itself, then: "How do you know that it's possible to always be deceived?" &c. Jul 17, 2022 at 13:27

1 Answer 1


The simplest and most powerful argument according to my opinion is the following:

There is no reason for the universe to give the impression of something while something completely different (and not simply some refinement) is the actual case.

And that is it!

There is no floating skeptic, every skepticism is a kind of assertion. It asserts the presence or lack of something. And every assertion needs to be based on something, even if it is self-evident. If you deny that, then our assertion above is also skepticism, thus irrefutable.

Radical doubt in this sense presupposes additional reasons (even unstated), which themselves should be first radically doubted.

If the impression the universe gives us is a basic clue to support our argument, the radical doubter really has none to support his superfluous reasons. If he had such clue, our argument would still be true since then the universe would provide that impression one way or another. Furthermore, if the radical skeptic provides some clue, he has either to accept the clue without further doubt, thus refuting his position, or go into an infinite regress. In other words, we are entitled to clues, while the doubter to none.

For example:

  • What if the universe was created five minutes ago? We have clues to the age of the universe, why doubt them?
  • What if I don't exist right now? Then who asks?
  • 1
    I congratulate you, it seems to me an excellent answer
    – Zeruel017
    Jul 17, 2022 at 21:24
  • @Zeruel017 thanks, you may find this answer useful
    – Nikos M.
    Jul 17, 2022 at 22:29
  • @Zeruel017 you may be interested in this answer too
    – Nikos M.
    Jul 18, 2022 at 13:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .