AJ Ayer's Verification Principle Refuted 

• Diarmid Weir Tues 28 April 00:42

Has anyone read the AJ Ayer/Copplestone {acually Copleston} debate? I find it significant how the thing was supposed to be an examination of Ayer's verification principle, yet it was Copplestone who ended up on the defensive!
• Nicholas Beale Tues 28, Apr 1998 15:49

Interestingly, Ayer and his silly self-refuting ideas have been consigned to the dustbin of philosophical history, whereas Catholic philosophy is still going strong. (PS I am an Anglican, not an RC)
• Diarmid Weir  Thu, 30 Apr 1998 16:18

...Your belief does require 'verification' - your personal evidence - so AJ Ayer wasn't quite so silly after all!
• Nicholas Beale Thu 30 Apr 98 19:00

 I have personal experience of the moon, and also have objective evidence that it exists.  If someone blind can't see the moon, then we discuss the objective evidence.  It is not I that need external proof, it is the person who does not already know, and who mistakenly supposes that, because faith is involved, there can be no evidence. The fact that 'subjective' and 'objective' criteria converge does not undermine truth, but strengthens it.
That's not what Ayer meant by 'verification' and his silliness was to assert that "all meaningful statements must be verifiable" which is self-refuting.
• Diarmid Weir Fri, 01 May 1998 02:24

Do you mean that the assertion itself cannot be 'conclusively' proved? Neither it can, but it's a good working hypothesis so let's use it until it breaks down. Can you give an example of a meaningful statement that isn't verifiable? (God is Love won't do - particularly since both you and Father Gregory tell me you have verified this through subjective experience!)
• Nicholas Beale Fri 1 May 18:10

"all meaningful statements are verifiable" can't be verified in Ayer's sense. That's why its self-refuting.
• Diarmid Weir Fri, 01 May 1998 02:24

The standard of proof for this statement need be no greater than for any other. Again I challenge anyone to produce a statement which is not verifiable but which is meaningful. Until this is achieved Ayer's statement is not refuted.
• Diarmid Weir Fri, 01 May 1998 21:05

Just to really confuse the issue, I actually believe that I can prove, to my reasonable satisfaction at any rate, that 'the steadfast willing of the ultimate good' of every other human being is the logical conclusion to be drawn from AJ Ayer's proposition that you all hate so much!
   Takes all sorts - doesn't it? The arguments are somewhere on my Web Site at http://www.abel.co.uk/~febl/tst/frame.htm. Click on Rabbie Burns!
• Nicholas Beale Sat 2 May 12:30

You seem to have missed the point.  You cannot 'verify' the statement "all meaningful statements are verifiable". Hence it cannot be true.  If you think otherwise, produce a 'verification' for it.
  However, although no-one has produced a verification, becasue it is rather wooly it is not possible to prove conclusively that none is available. But the following is conclusive.

Conclusive Refutation

If M is an arbitrary Turing Machine the statement "M terminates" is  meaningful.  However it is a theorem that there is no decision-procedure that allows you to determine whether any given Turing Machine terminates.  Therefore, in general, the statement "M terminates" is not verifiable. QED.

Comments continue

Furthermore  if T is a well-formed formula in a logical system L, the statement "T is a theorem in L" does not have a decision-procedure and is therefore not, in general, verifiable.  Thus until recently the statement (aⁿ + bⁿ = cⁿ => n<3), whilst obviously meaningful, was not 'verifiable'.  Incidentally, it is idle to object that these refuations are in the realm of pure logic and therefore do not count - clearly any conclusive proof or refuation must be in the realm of pure logic but if the 'Verification Principle' is false in the realm of pure logic it is also false in any consistent contingent system as well.
  I find it somewhat amazing that anyone was taken in by Ayer, but then his and Russell's project was to subvert morality by 'cleverness', and this has always attracted a following (see The Clouds, or indeed Genesis).
  You're a doctor - here are just a few examples of statements which are not 'verifable' but, if you treated them as meaningless, you could lose a mapractice suit and be struck off!
a. I felt a sharp pain in the left side of my chest yesterday.
b. My life doesn't seem worth living.  I don't love my wife. I feel suicidal.
c. My wife doesn't love me any more,  I think I'm going to poison her.
d. In my professional opinion, the best treatment for this patient is chemotherapy.
e. I'm afraid I took too many tablets this morning.
f. I'm not feeling at all well. I'm feeling much worse today than yesterday.
 You believe in evidence-based living. Here at least is conclusive evidence that you should abandon your faith in Ayer, and if you followed your principles through you might get closer than you think to faith in God.
• Diarmid Weir Fri, 01 May 1998 21:05

I'm sorry that I don't follow your arguments using equations, but your examples from medical practice don't hold up. For something to be verifiable doesn't mean it can be proved beyond doubt. I have already made this clear.  Nothing can. It has only to be possible for there to be some evidence which makes it more or less likely. The examples you give could all have some evidence to support the truth or otherwise of the statements made, although I agree that they might not in practice. To look for this evidence is not the same as ignoring the statements. The amount of evidence required to act on the statements (including the evidence of the statements themselves) would vary according to the significance of acting or not acting. 'Conclusive proof' is (fortunately) not required. If no evidence subsequently appeared to support or refute the various statements you produce, they would actually fairly quickly cease to become meaningful in
practical terms, because they would provide no basis on their own for any further definitive action.
   I know it all sounds a bit circular, but the advantage is that you keep moving on to the next question, until you get to some important ones - like why are so many people unhappy? Why are there wars? Why are some people so poor when others are revoltingly rich? If you believe in a 'Loving Ultimate Creator' then everything comes to a bit of a dead stop. Perfectly rational questions like: What are LUCs made of? Where do they come from? What do they do? Why do they do it? have to be disallowed by definition.
   Which is why I repeat (in slightly different form) the question that you haven't answered: In what specific situation does it become 'non-trivial' to prefer Red or Green - and why? {these last 2 paras raise new issues so are repeated here}
• Steven Carr Sat, 2 May 1998 18:27

Surely Ayer said that all meaningful statements can in principle be falsified ie you can think of facts which would, if they ever occurred, make the statement false.Did he really say that all meaningful statements are verifiable, as it is hard to verify things beyond all dispute, yet possible to falsify things quite easily.
• Diarmid Weir Fri, 01 May 1998 21:05

But as I am trying to make clear, even Ayer admitted that no statement is verifiable absolutely, because even if every observation up to now verified a statement, there is no guarantee that the next observation will not falsify it.
   The idea that statements can never be conclusively verified but can be conclusively be falsified seems to originate with Karl Popper, but I don't think this makes sense. To falsify something conclusively is simply to verify its negative conclusively, and we know that can't be done. If x = y is shown to be false on one occasion that doesn't mean that x not = y is always true. the reason that he came to believe this is presumably that he couldn't find any other way to explain our ability to predict future events from the past. I think that I might have a better, albeit rather bizarre, theory!
• Nicholas Beale Sat 2 May 12:30

As a matter of history of philosophy, Ayer claimed that propositions were meaningless unless (empirically) verifiable ie that there was "a procedure for determining whether it was true of false" (I can't find my copy of Language Truth & Logic - this is from Scruton 96 but it's accurate.  Note that this is not the same as "a way of exploring the likely veracity"). In particular, this (supposedly) implied that all ethical and metaphysical statements were meaningless. This 'verification principle' is conclusively refuted above.
   Popper, a much more considerable figure, proposed a Falsification Principle in which he suggested that a scientific statement was meaningful if falsifiable.  The point is that (for all x) P(x) may be impossible to verify but easy to falsify.
   In 1992 Anthony Kenny, then President of the British Academy, could write (p33) "the criteria of meaningfulness which Ayer...used to attack theology were, by the end of the seventies, no longer taken seriously", in 1996 Scruton (p18) says "logical positivism {Ayer's 'school'} no longer has a following"
  Let's address your other (more interesting) points here.
• Diarmid Weir Sun, 03 May 1998 22:39

Oh well - Nicholas Beale and I will have to agree to disagree for now!
  Just one last thought on this topic. If my interpretation of logical positivism was right, then it would hardly be expected to have a following among professional philosophers, because they would essentially be redundant! I suspect that is why Ayer himself failed to quite follow his own logic through. After all, he ended up believing that death was oblivion - which is distinctly unverifiable!
• Nicholas Beale 24 May 98 {Diarmid was still disputing this point}

Can you explain the fallacy in the argument then:
1. "all true statements are verifiable" (H1) is a statement.
2. H1 is not verifiable.
3. Hence H1 is not true QED.
• Diarmid Weir Mon, 25 May 01:24

The fallacy is that you are looking for absolute truth - which cannot exist in the real world of uncompleted human experience. The closest theoretical approximation to absolute truth would be to ask the opinion of every human being who had ever lived  in the world, assuming they had access to the sum total of all human experience so far. (Were this not true then democracy would not always be the best form of government). On that basis H1 could win the majority vote! Even if it didn't this only shows that it hasn't (yet) been verified, not that it is intrinsically unverifiable.
  You keep getting hung up on the idea that verification = absolute proof. 'A hypothesis cannot be conclusively confuted any more than it can be conclusively verified' - Language, Truth and Logic (AJ Ayer) p19 (Penguin edition). Absolute proof requires an infinite number of verifications - therefore it never happens - but you can certainly get enough verifications to work with. This applies just as well to H1 as to any other hypothesis. It might turn out to be wrong - but it's the best (and simplest) model of our universe we have so far. It certainly contains fewer self-contradictions than ELUC.
{rest of post here}
• Nicholas Beale 25 May 98 14:00

{a}It is an absolute truth that 2 + 2 = 4 and that given (1) and (2) above (3) follows.
{b}Opinion polls are a hopeless guide to absolute truth, and if you are going to allow them as a form of 'verification' than your 'principle' simply becomes vacuous.
{c}H1 is not a 'model of the universe' it is principle that has been abandoned by all philosophically literate people because it has been logically refuted.
{d} By contrast, ELUC is, in a very deep sense a "model of the universe" and is only resisted by people becasue they set their 'prior probabilities' to very low levels which make them almost immune to any evidence. {BTW Ayer is obviously wrong that a hypothesis cannot be conclusively confuted. "Labour could not win the 1997 election" is a hypothesis.)
•  Diarmid Weir Mon, 25 May 18:49

{a}So absolute it's a tautology. To make it clear - we can rewrite it as 1+1+1+1 = 1+1+1+1 ! {given that + is associative NB} It's all a matter of symbols.  As soon as you substitute real things for the symbols, you have something which is not absolute, and which can be verified - but not conclusively. For example 1 bag of sugar + 1 bag of sugar = 2 bags of sugar. Is this always true? What if we use volume or weight, or the number of grains? How do we decide on the acceptable level of agreement between the values? If we're buying it in the supermarket, a few grams, a few centilitres, or a few hundred grains are irrelevant, but for a scientific experiment much greater accuracy would be required.
{b} I wasn't talking about opinion polls, I was talking about the equivalent of elections - are they a hopeless guide?
{c} It's a very good guide to action in the universe - which is what matters. So I'm philosophically illiterate? That's an easy way of avoiding logical argument. I seem to remember your quoting Roger Scruton before - if he's your definition of philosophically literate, I'm glad I'm not! Your refutation using the 'Turing machine' didn't convince me because as far as I can gather, it is not a device that can exist in the real world of human experience. Can you direct me to a real-world refutation of the verification principle?
{d}Hey, come on! What is faith if not a 'prior probability' set to 100%?
• Nicholas Beale 25 May 98 19:30

{a} You still seem to think (with Ayer) that tautologies don't tell you anything interesting: he was wrong about that as well.  "aⁿ+bⁿ = cⁿ => n<3 (for a,b,c,n +ve integers)" is also a tautology and an 'absolute truth' - try reducing that to an obvious-looking set of symbols.  The fact that p₁ x p₂ = k (for some large primes p₁ and p₂) is a tautology but tells you how to break a cypher and could be worth millions.  Clearly there is an issue of whether the axioms are valid for the system under consideration, but if you define + and = consistently over 'bags of sugar' then 1 bag + 1 bag = 2 bags.  Similarly H1:"all true statements can be verified" and O1: "H1 cannot be verified" absolutely imply "H1 is false".
{b} You mean referenda I think (Pose a question: do you agree -Yes/No).  They are clearly a guide to people's opinions and clearly no reliable guide to truth.  Furthermore, any question which could be written down could be put to a referendum, so if this is included in verification the "principle" is meaningless.
{c} You must be using a computer - a Turing Machine is just the logical formulation of a computer running a program.  It is impossible to make a computer program which will verify whether an arbitary computer program will terminate.
{d} Faith is an act of freewill, which is rational if the posterior probabilities are sufficiently high.  If you start with a prior of Red of only 1% you will end up with a posterior probability of over 99.9999%, based on the evidence in the Beale/Howson debate.  We've already discussed how uncertainty is compatible with faith.
•  Diarmid Weir Mon, 25 May  23:02

{c} I don't really follow this - according to your references a Turing machine is a 'theoretical computer' with an infinite tape, so it's not the same as my computer!  The only sense I can make of this is that you are saying that it is 'absolutely' impossible to say in the present that some defined event will certainly happen in the future, given anything other than an infinite timescale. Beyond that...........?
{e}  If 'verification' as it was conceived and not as it is consistently misinterpreted by you, has been logically debunked using real-world examples, can you direct me to an appropriate reference?
{f} Final thought - then I'm going off to make damn sure the meek inherit the earth, even if you're not!
  Would it be possible to communicate with someone brought up by wolves or whatever, by language alone? Or would actions be needed to give the language some meaning?
• Nicholas Beale Weds 27 May 10:30
  {c} No - The question "does a given Turing Machine Terminate" is clearly defined at present, and not a prediction about future behaviour.  However it cannot be "verified".  (this is actually logically equivalent to Godel's theorem).   
  {d} I suspect that any modern text on philosophy that bothers to mention it will tell you that the "Verification Principle" has been refuted. See eg Scruton.  You can only logically de-bunk something using logical examples which are abstractions of the 'real world' (like Turing Machines).  We are doing philosophy here, not bricklaying.
  {f} Dunno.  Probably.  This seems a bit off the subject:).

 

 

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