Why did Wittgenstein think that only something that could be doubted could have meaning?

Question

One of the reasons Wittgenstein thought the exclusive use of ostensive definition failed was because it opened the possibility that a given symbol's meaning was sourced from whatever sensation someone was having at the time, so that a symbol's meaning was whatever seemed to be the case to the private linguist.

He then concluded that in this situation truth and falsity couldn't be rationally talked about. This point was made because Wittgenstein thought that the values of truth and falsity could only apply to cases where the one or the other could actually be applied.

In other words, Wittgenstein thought that only symbols that could be doubted could have meaning and the values 'truth' and 'falsity' applied to them.

But why is this?

It seems to be the case that Wittgenstein thought that otherwise what was being dealt with was a tautology, where the sense of meaning was lost.

But couldn't there be other meaningful self-evident sort of statements where what's occurring isn't a tautology and where it wouldn't be reasonable nor conceivable to doubt?

Answer 1

it's kinda the same as popperian falsifiability in science.

developing a new proposed theory that, in essence, says nothing different than the old existing theory does not carry new meaning. the old existing theory is good enough and the new theory is not falsifiable and may not survive as a viable theory. it's only if the new proposed theory makes some claim that differs tangibly from the existing theory, such that one can set up an experiment and observe the difference (or fail to observe it), only those theories are meaningful in science.

Answer 2

Basically, it seems to me that if A can be doubted, then ~A necessarily makes sense. But if A cannot be doubted, then ~A must be absurd - or, in Wittgensteinian terms, meaningless or senseless. Now, if ~A is true, then A is true, and if ~A is false, A is true. But if ~A is merely devoid of meaning, then A cannot be either true or false, implying that it is also meaningless.

It is difficult to tell, because Wittgenstein's language is often confusing, but that is what I gather of his position.