Emmanuel asked:
My question is based on the refutation that the Verification principle of the logical positivists cannot verify itself, but I feel personally that for the verification principle to verify a proposition empirically, it is verifying itself. Therefore I see verification principle being verified. And I term it self-demonstrable. What’s your own say on this?
Answer by Shaun Williamson
No I’m sorry but I don’t see any sense in your answer. The Verification Principle says ‘A factual proposition (statement) is meaningful if it can be empirically (directly or indirectly) verified by empirical observations.’
The Verification Principle is a proposition but there are no observations we can make that would verify it so therefore either the Principle is meaningless or it is an arbitrary assumption or it is a metaphysical truth or it is a truth of logic or mathematics. It doesn’t seem to be any of these things except maybe an arbitrary assumption.
The Verification Principle does not allow for self verification whatever that might mean.
The Logical Positivists recognised only two sorts of statements, those that don’t need verification (definitions, truths of logic and mathematics etc.) because they don’t make assertions about the world and those that do need verification.
Answer by Geoffrey Klempner
What Emmanuel is suggesting is a pragmatic justification of the Verification principle. Every time we use the Verification principle ‘successfully’ (whatever that means) we pragmatically verify its efficacy. I think some Verification theorists might be tempted to say this, but this doesn’t meet the objection.
Consider the principle, called the Humour principle, according to which the only propositions which are meaningful are those which are funny, i.e. those which actually make us laugh. If it doesn’t make you laugh, then the proposition has no meaning. No-one has seriously suggested this, or maybe they have, I wouldn’t know :-)
Is the Humour principle humorous? Suppose we tried it out on a sufficiently large sample of philosophers, and sufficiently many were provoked to laughter. Then that would be sufficient proof that the Humour principle is meaningful, at least by its own criterion.
In other words, the Verification principle fails a test which the Humour principle passes, or at least could in principle pass. The reason that the Verification principle fails is the interesting part. It fails because it is, in fact, an example of the very thing that the Verification principle was designed to guard against: ‘metaphysical’, or non-empirically verifiable propositions.
Ask a Philosopher 
The verification principle is proposition about what literal meaning is, what the phrase “literal meaning” refers to. Verifying or falsifying it is a matter of analyzing whether its description correctly matches how most people use the phrase “literal meaning” in practice as to what it refers to. So the verificationist account can be corroborated every time a statement that is acknowledge by everyone (or practically everyone) as meaningful translates into potential experiences, and it can be falsified if every a statement universally acknowledged to have meaning does not translate into potential experiences (because this would indicate that we do not use the word “meaningful” to refer to a statement’s capability of being translated into potential experiences). I’ve written more on this here:
http://www.skepticblogs.com/humesapprentice/2012/08/14/verificationism/
Also note that the position I advocate is a serious academic one, a similar position is also advocated by Professor Kai Nielsen of Duke University as well as Dr. Michael Martin of Boston University. Likewise, Daniel Dennett, Crispin Wright, Michael Dummett, and others have advocated one or another version of the verification principle.