Can every apparently true belief turn out to be untrue: and what is the word for this stance?

I would assume it would mean we have no knowledge: is that right?

Someone on a forum I use keeps derailing discussion with the claim that true propositions (all of them) can be proven to be untrue. They seem to really think that Einstein and theory-ladenness etc. proves it. They think Marx argues that absolutely everything about the world can be changed.

  • 3
    How can any true belief be untrue? Your first sentence seems to contain a contradiction.
    – Dave
    Mar 24, 2016 at 19:42
  • yes i know. it seems totally trivial that it's inconsistent. i've tried arguing with them, but they are terrible
    – user6917
    Mar 24, 2016 at 19:43
  • i could use a definitive reference or just a very neat (clear and incontrovertible) argument
    – user6917
    Mar 24, 2016 at 19:44
  • True wisdom is knowing that you know nothing, Our species does like to feel superior by giving names and categories to things and then deluding themselves into the belief they know said thing or category, when in fact, we know nothing about everything. Mar 25, 2016 at 9:02

4 Answers 4


The name is nihilism. Literally, nothing could be true.

If 'master signifiers' are empty, as Lacan insists, and language is entirely conventual, then no statement has a fixed meaning, and the meaning of any statement can simply change, in the sense that it will begin having different psychological effects. We know that it will only change into something to which the users can adapt, but it is unanchored and will not stay fixed. The collection of such statements make up a composite theory of effective statements, that will create approximately the intended effects on a listener.

Since their agreement or disagreement is relative to the current composite theory and the theory is going to be superseded continually, any effective statement will have at least some edge cases where it will be wrong, even when it is made. To the extent the next not-yet-known theory is equally both true and false, if likely to be closer to reliability, you can claim all the approximations are all false.

Being able to interact productively with others by using effective statements can still be considered knowledge. It is not 'justified true belief' but it is 'memory with effective power'. (The former standard fails anyway. To the degree you know steps to a dance, or when to say the pledge of allegiance, or you know the 'effable' names of various people's cats, you have knowledge. And those are the latter, but not the former.)

From that point of view, if you take some Platonic or Aristotelian definition of the word 'true', you could argue that nothing is thoroughly/permanently/completely true. But it involves starting out from two different extremist positions, demanding the truth is classically absolute, while the mental contents that statements are made out of is conventual and adapting.

This makes no sense, really. If you know the meaning of true will change, why not give it a useful definition? In the Wittgenstein sense, doing otherwise is a pointless word game rather than a meaningful language game.


This is "global skepticism" or, sometimes, the "skeptical hypothesis".

If the assertion "all of your beliefs are untrue" is accepted, then, yes, under a JTB based definition of knowledge you'd have no knowledge. Note that the if the assertion is "It is possible that all of your beliefs are untrue", then there is no firm conclusion that you can draw about which of your beliefs are true or not. (If you take a more Popperian definition of knowledge then issues of truth dissolve and are replaced with considerations of usefulness.)

In the cases that I've seen this brought up, the person invoking the skeptical hypothesis is equivocating between knowledge and certainty.

  • the point about certainty makes sense, but i'm not sure i think they have enough good will to appreciate that they could've equivocated anything
    – user6917
    Mar 24, 2016 at 20:33

I should be very curious to hear this person's response to Descartes' thought experiment (in Meditations 1 and 2, at least). He spends Meditation 1 razing the structures of his knowledge with the bulldozer of doubt, but he eventually clues in at the beginning of Meditation 2 that the bulldozer doesn't drive itself. He has to exist to doubt, and he cannot plausibly doubt his own existence.

Where he goes from there, with the reconstruction of the world based on what he can know from the fact of his own existence, does eventually go off the rails. But that much, at least, should provide a firm foundation on which to build certain knowledge.

I should also be very curious to know out of which part of Marx they're dragging the proposition that absolutely everything is changeable. I'd bet that if Marx does say it, he intends some limits on it.

  • 1) Schizophrenics an people with derealization disorders sometimes doubt their own existence, and see their selves as epiphenomena of some accident, or some conspiracy. So not every mind offers Descartes solution. Is the healthy mind right, or does the one we (as the normal) consider disbalanced have something to teach us? 2) The part of Marx that follows Hegel. Dialectic puts everything in question continually. Whatever change is truly needed to avoid the current impasse is taken, with no specific reservation.
    – user9166
    Mar 28, 2016 at 16:22

Can every apparently true belief turn out to be untrue:

Yes, of course..

and what is the word for this stance?

In Sanskrit it is called Chaithanya. (A word almost equivalant to 'Consciousness')

I would assume it would mean we have no knowledge: is that right?

No. By the word 'knowledge' if you meant 'the knowledge about this mundane world', the answer is 'Yes', because Chaithanya is formless and indistinguishable.

I believe the Theory-ladenness and the given Marxian views are formulated by partial analysis from the information/facts that got through outer-eyes where the answers to your questions are based on the Truth realized through inner-eyes of Rishis. Also, the latter has the ability to dissolve the the first two views. And it is not from one particular person but many persons who discovered the changeless 'behind' all the changes.

I don't know the details explained here can clear your doubts. I know nothing about this. I am only a learner.


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