> As of writing this comment, I have five fingers on each of my hands.

Well, if you are not a brain in a jar, maybe. As far as I am concerned, I don't have any undeniable evidence that you even exist, nor that I have hands.

That's a pretty useless kind of skepticism, but as long as you are going for objective "truth" you must face that kind of problem.

> Well, if you are not a brain in a jar, maybe. As far as I am concerned, I don't have any undeniable evidence that you even exist, nor that I have hands.

If I am a brain in a jar, do I have hands?

Well, then I would still have virtual/simulated/apparent hands. And, when I say "hands", by that word I mean those virtual/simulated/apparent hands. Hence, even in that scenario, I do indeed have hands.

The ordinary meaning of the English word "hands" encompasses both "ultimately physical hands" (of the kind I might have if I am not a brain in a jar and also not some AI living in a computer simulation) and also "simulated hands" (of the kind I might have if either of those hypothesises were true). So, either way, it is true that "I have hands". When I say that, I am not expressing any opinion on the truth or falsehood of those sceptical hypothesises. If I wanted to express an opinion on those sceptical hypothesises, I need to explicitly exclude them, i.e. "I have ultimately physical hands".

I believe what he meant is that all your “truths” are the same as the believe in the example. You have reasons to believe that those things are true, and certain observations made by you corroborated your hypothesis, leading you to conclude they were true.

For instance, I have 5 fingers in each of my hands: you see them, you use them, so they must exist and be real. I’m no philosopher, but I suspect their arguments would go towards how can you trust your senses and perception to prove ideas about reality...

What is your definition of truth? It seems to me like this is an issue of abstraction layers. The truth can be simply described within one layer, but adding layers requires more precise language.

It's a bit like arguing "I" don't move my arm because neural signals trigger muscles to move the arm. Both are true, the language is just more involved if we don't share a common definition of "I".

you only “must” face that “problem” when dealing with people who are either overintellectualizing uselessly, as you note, or with assholes. the distinction is slim!

Even then it depends on your definition of "I". If this reality and self is a brain-in-a-jar simulation, I still have five fingers - the brain may not, but the brain isn't me.

Though, this is a good example of what I meant by precision of truth. "I observe five fingers" is more accurate, and there are still better phrasings, but individual inability to precisely communicate truth does not imply truth does not exist.

Not merely pedantic miscommunication. What do you mean by "hands"?

We understand what hands are, but imagine trying to write a program that infers what hands are, and works automatically for non-humans as well.

And then it has to work for people who don't have five fingers, too.

There are a lot of assumptions embedded in words. None of these are generally interesting, which is why they're best ignored. But they exist.