I know I'm alive
Just as an (hopefully not too distracting) aside: Wittgenstein argued that, in normal everyday discourse* (as opposed to academic philosophy) that “know” is, at best, superfluous. In the Philosophical Investigations, he imagines a passerby who overhears a discussion in which W’s interlocutor says: “I know that’s a tree!” (Note the emphasis.) W says to the puzzled passerby: “Don’t worry. This fellow isn’t crazy. We’re just talking philosophy.”
Imagine again the addition of emphasis: “I know I’m alive.” How could there be any doubt? The same with the other examples. If there were doubt, to what could you appeal?
And this is where I think the Meno Paradox becomes a sophistic misapplication of deductive syllogistic – hence my post about inductive versus deductive logic.
[W’s On Certainty was an extended exploration of this question, in response to G.E. Moore.]
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* Which W argued was adequate to most of our everyday communication, and that academic philosophy (epistemology) often confused what is apparent.