I am struggling to understand a point about Verificationism, which as I understand it is a doctrine that says that a statement is only meaningful if it can (in principle) be proved true or false.
One interesting aspect of this doctrine is that is suggests that the sentence "The Earth is very old" is meaningless, as it is impossible to verify whether the Earth really is very old or whether we and it popped into existence a few seconds ago with all our beliefs about its age 'pre-coded' in our heads and various clues as to its age (fossils, radiometric dating etc) planted there to trick us if we choose to investigate in the future.
But doesn't this mean ANY statement is meaningless under a verificationist account, since it is impossible to distinguish between "P" and "I, and anyone I choose to consult on this topic, are being systematically deceived into believing P"? Can a verificationist give an account of a sentence that she would find meaningful?
Thanks very much
Your class of problematic cases is problematic for verificationism only on the assumption that the distinct sentences you pair with each other differ in meaning (refer to distinct propositions). But this is what a verificationist might well want to deny. She might say that, if two sentences coincide in their truth conditions, then they have the same meaning (refer to the same proposition, make the same claim). And this claim can then still be meaningful because empirical evidence can be brought to bear on deciding whether this claim is true or false. Consider (A1) The universe is between 6.23 and 6.24 billion years old. and (A2) The universe was created very recently but everything has been arranged to suggest to human inquirers that the universe is between 6.23 and 6.24 billion years old. If no empirical evidence can possibly decide between these two sentences, then they express the same claim or proposition A. And this proposition is meaningful because empirical evidence can...