We have to start somewhere, and it seems that a sentence's being true is at least as good a place as any. I mentioned previously the circularity of analysing truth in terms of knowledge when knowledge is defined in terms of truth.

Hold truth steady. Then belief that p is holding p to be true, even if it isn't. And knowing that p excludes p being false. The structure is consistent.

in fact in the case of metaphysics I would say there can be no certainty at all, that it all comes down to plausibility, because we are dealing with the non-cognitive.
— Janus
If metaphysics is about the non-cognitive (which needs a bit more fleshing out), are we sure that certainty and plausibility even apply? — Ludwig V

That's an interesting question. If everything we cognize is counted as "physical", then would not metaphysics, thought of being what is beyond the scope of physics, or any other science, be thus taken to be dealing with the non-cognitive?

Why do we need to talk in terms of 'knowledge that' when nothing is lost by talking instead of 'justifiably believing that'?
— Janus
Well, if there were something to be gained, it might be a change worth making. But so long as we distinguish between true beliefs and false ones, the issues remain. — Ludwig V

I want to note that I'm not saying we don't know anything—I'm saying that in those cases where we can be said to know something, we know (again, radical skepticism aside) that what we know is true. It seems to me if we do not know that, then it doesn't count as knowledge but as belief. It could be justified belief, and then it would that its truth is highly plausible, but that still falls short of knowing it is true.

It seems to me that your meteorite example with the conclusion that you should "take your cue from society" and ignore the mere possibility just counts as an example of a justified belief—you don't know that a meteorite is not going to strike you on the head, but you could be said to know that the chance of its happening is miniscule, so knowing that it is highly unlikely means that believing it would be to believe in an extremely implausible event.

If it is wrong to believe something that might not be the case, then, presumably, it is equally wrong not to believe something that is the case. The more cautious you are in avoiding false beliefs, the more you risk not accepting true beliefs. — Ludwig V

I don't know...perhaps you are misunderstanding me—I'm not talking at all about being cautious in trying to avoid false beliefs. but about avoiding thinking and saying that I know something if I cannot be certain about it.

We can only pretend something that is possible. So if something is possibly false and we can pretend to know it, then it must be possible to actually know it. — Ludwig V

I'm not certain what you are saying here, but the question that comes to mind is whether it is possible to know something without knowing that know it. The very idea just seems wrong to me. JTB does seem to make this possible, and for me that is to its detriment.

The Matrix Hypothesis I think is absurd, because it posits that there is a real world in which the virtual world we inhabit is sustained, and this means the need for explanation is just pushed one step further back.
— Janus

But Descartes' doubt isn't about explanation. He believes it's possible to doubt whether my experiences are veridical -- that is, of the things they appear to be of. He's not questioning experience in general. The Matrix hypothesis would represent such a doubt. — J

I'm not saying that Descartes considered the Matrix hypothesis at all—I don't think he did— because as I said I think the Evil Demon scenario is really very different, apart form the idea of being radically deceived in both scenarios.

In the Matrix scenario there is no skepticism about the real world—in fact that is what those who see through the virtual illusion are trying to get back to. If Descartes considered this he would still be faced with the question of being able to doubt the purported real world just as much as he can doubt the virtual world of the Matrix.

By introducing "explanation" I meant to refer to the question as to how we could be certain of the reality of anything. We can doubt the virtual world, but how can we be certain of the reality of the world within which the Matrix is sustained?

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...how can we be certain of the reality of the world within which the Matrix is sustained? — Janus

Bertrand Russell had just finished giving a public lecture on the nature of the universe. An old woman said “Prof. Russell, it is well known that the earth rests on the back of four elephants, that stand on the back of a giant turtle.” Russell replied, “Madame, what does the turtle stand on?” The woman replied, “You're very clever, sir. Very clever. But it's turtles all the way down".

It's VR all the way down...?

Yep, I guess it could be.