The Refutation of Truth Relativism and Truth Subjectivism (Plato's Theaetetus)

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[familyshare]

Logic itself (assumes, requires) absolute objective truth

[philosopherseeker]

Another great video Mr. Chapman. A good, comprehensive compilation of knowledge and I like your matter of fact way to explain it. In my opinion Plato follows a brilliant line of reasoning here- I've seen the argument before but not this in depth.

What would you say to someone who, when you point out that it's self-undermining to say "there isn't any truth", he responds: "Well, there's no truth EXCEPT for this truth that I've now uttered".

It seems to me to be commiting the special pleading fallacy. It also looks to just be a semantic trick to say "there isn't any truth" but I'm having a hard time pin pointing it.

[MatthewMcVeagh]

I agree with what you say. Nevertheless it's interesting - and for other questions important - that even with an absolutist sense of truth there is still a relativity of truth to the correspondence between statement and reality.
There are plenty of statements that are ambiguous, or whose truth-value depends on context or timing, in which there is not a simple truth or falsehood. Ultimately the truth-value of statements depends on their meaning, and their meaning does not exist (in my opinion) in any objective or external way in language or the world; it only exists in the minds of creators and receivers. The truth-value of particular statements therefore depends on the meaning intended by the creator, or that inferred by a receiver.
We should therefore carefully distinguish between 'Truth' as in 'The Way That Things Are' in reality, and the 'truth' of statements or propositions corresponding to reality, and specifically to that Truth that consists in The Way That Things Are.
To claim that that first Truth is relative implies we live in a chaotic universe where nothing is really any particular way; if it is relative to belief it would mean that reality changes every time we believe a different thing, and if two different people believe different things about the same thing, there must be two different realities to it.
To claim that real Truth is subjective is to claim that it's not real; that we are all living in our own subjective universes.
By contrast to claim that the truth of particular sentences depends on factors like context, vagueness or sense/reference matchup is perfectly valid.
However I don't think this gives solace to the Truth Relativists that Plato and Aristotle are critiquing. Then again I don't see how Plato infers that if truth relativism is true there are no false beliefs. Why can't it be that there are true and false beliefs but that the true ones vary according to who's holding them? (I mean apart from all the reasons you gave as to why truth relativism isn't valid anyway.)

[jvt_redbaronspeaks]

thanks for the video. this is an important lesson that is being left out of, at least some if not a lot, modern schools. I've been argueing with a couple friends who claim to be relativists, but they make all sorts of truth claims. I don't think they even know what relativism means. your/Plato's syllogism will help me explain the silliness of their position.

[familyshare]

Logic requires (defines, assumes) absolute truth. "Relative logic" neither proves nor denies"relative truth". Relative injects relative "sometimes" in every logic statement.

[mcrotty]

I had a good philosophy professor who clarified on this subject well. The refutation of truth relativism is given by the relativist themselves by asserting their own position as true, which by implication asserts the exact truth of the opposite position, therefore truth relativism cannot be true because it also asserts it's non-truth as a truth. A liar who tells the truth is not a possibility because if they were telling the truth they wouldn't be a liar. True for me just means opinion, whereas these can be right or wrong in relation to the truth. All beliefs are true in that it is true that they are had by a subject, it's your truth, but the content of all belief is not necessarily true.