Poll 2 on the validity of a more complex argument

Discussion in 'General Philosophy' started by Speakpigeon, Jan 18, 2019.


Is the argument valid?

Poll closed Feb 17, 2019.
  1. No

  2. Yes

  3. I don't know

    0 vote(s)
  4. The argument doesn't make sense

  1. Speakpigeon Valued Senior Member

    This is a gross misrepresentation of the facts.
    This thread is a poll and the only question asked of you is as to the validity of the argument. The OP doesn't ask for a formal proof.
    So, look at the OP if you don't believe me:

    This thread is a poll on a logical argument.
    Thank you to vote before posting any comment on the argument (you can change your vote if need be).
    Here is the logical argument:
    For all we know, A may be the state of some unknown part of B;
    C is determined by the state of some unknown part of B;
    Therefore, for all we know, C may be determined by A
    Is the argument valid?

    That's all there is to it. This thread is a poll and the question is "Is the argument valid?". Nothing else. So, you misrepresented the facts.
    I happen to think myself that it is rather obvious that the argument is valid and let's say I wanted to check if it was also obviously valid for all of you.
    And then, instead of replying to this fairly simple question, people have started to make wild and irrelevant comments.
    Don't complain to me.
    Hey, that's good, you've understood the idea behind the argument.
    Not quite the argument itself, though.
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  3. Baldeee Valued Senior Member

    Adopting it doesn't require such a modal approach, though.
    As I think Sarkus mentioned in his first post on the matter in one of the other threads, far simpler to just adopt a standard classic logic approach, and then question the soundness of the premises.
    Far easier to assess the validity of the argument, will help avoid the weakening of the argument through what would be (in classic logic) the undistributed middle, and focuses the attention on getting the premises as strong as possible.
    He can't.
    Yes, this would seem to be it.
    He seems to want an argument where the premises are considered by most to be true, rather than have people question the soundness.
    But doing so requires those premises to be declarations of possibility rather than of necessity.
    This makes them weaker.
    If you're talking about speakpigeon's argument then I think it is valid: as long as "part" in the first and second premises have the possibility of some overlap, then if the premises are true then the conclusion is true.
    It might not be very likely, but that doesn't affect the validity, I don't think.
    Which words are you thinking need investigation?
    If I may have thought of a number (possibility), and you are thinking of a number (necessity), it seems intuitively valid that I may have thought of the number you are thinking about.
    Unlikely, but possible.
    And that possibility could well be all that is required for the argument to be valid.
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  5. Quantum Quack Life's a tease... Valued Senior Member

    It is interesting from the view point that if Copernicus used your method he would have been able to treat his beliefs as being speculative instead of factual.
    If he stated "For all we know the Sun orbits the Earth." instead, he would have been also stating that there is doubt about what is and was currently held as fact at the time thus opening the door to further thought on the subject.
    His claim therefore would not have been an argument but a speculation about the significance of the Earth regarding the Sun.
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  7. Quantum Quack Life's a tease... Valued Senior Member

    What is the difference between the following two;
    A = B
    C = A

    For all we know
    therefore for all we know

    The first thing that comes to mind is that the second position turns a logically valid claim into a speculation of validity instead. A self-doubting argument, perhaps?
  8. RainbowSingularity Valued Senior Member

    the 1st example is algebra
    the 2nd example is philosophy
    Quantum Quack likes this.
  9. Baldeee Valued Senior Member

    Both forms are valid.
    The difference is in the strength of the conclusion.
    In the former the premises are strong and the conclusion is thus strong.
    In the latter the "for all we know" introduces weakness into the premise, and this translates into the same weakness in the conclusion.
    But it is a valid argument nonetheless.
    Quantum Quack likes this.
  10. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

    Ah, playing a variation of the Galileo Gambit, I see. One could utter this statement of yours after they are challenged on any claim at all... and it does nothing to the truth or otherwise of what they claim. It simply makes them look like an arrogant fool. And, channelling my inner Sagan for a moment, bear in mind that while people may have laughed at the idea of the earth revolving around the sun, people also laughed at Bozo the clown.
    An appeal to consensus from a group that clearly has no particular skill in modal logic? Yeah, that'll get you far.
    Why not go the easier route, post a syllogism that uses classic logic, and then debate the truth or otherwise of the far stronger premises. It amounts to the same thing. Or is your desire to use premises that can be more easily accepted as true your overriding concern, even if it limits the strength of your conclusion?
    So you really have nothing to offer here. You post a question and are unwilling to discuss it in a manner conducive to actual discussion. You throw your toys out of the pram when you don't like what people say. So why are you here? To poll a group of people not particularly versed in modal logic whether their "expert" opinion is that your argument is valid or not?
    So you're working on "its valid until someone can prove it isn't"? What is the ultimate purpose of your argument? Why not post a form that is far easier to determine its validity (I.e. using classic logic) and then debate the truth or otherwise of the stronger premise? At the moment, as surmised by JamesR, and explained in more detail by Baldeee, your argument may be valid but the conclusion is incredibly weak. And of no more overall worth as an argument than a classic argument would be, once full discussion of the premises has been undertaken.
    Is your intention to try to argue that consciousness determines what we do? If so, crouching an argument in modal terms is not going to get you there any quicker, and in fact more slowly, than a classic approach, as you'll waste time over assessing whether the argument is valid. And then to be meaningful you still have to go through establishing how things actually work in our world, rather than work with simple notions of what is possible in at least one conceivable world.
    If you can't work out how dissection of a frog doesn't help you understand the frog, maybe you're in the wrong field of study. Furthermore, if you can't provide argument as to why you think your own argument is valid, why should others post any explanation as to why they think it invalid? As it is, those people, myself included, have posted far more about why they think it invalid than you have posted as to why you think it valid.
    So stop being a hypocrite, stop being arrogant, stop being a troll. Can you do those things for us, please?
    "You can't prove me wrong therefore it's right!"
    Given your modal approach to the issue, one has to question why you have gone down this route if you are at all interested in anything other than modal logic itself. And if not, why you would bother seeking responses from a group who clearly aren't able to help you. The one person who has offered anything formally is one who says they don't know if it is valid or not. But you seem to be happy taking the consensus of everyone else, who have, it seems, even less grounding in modal logic.
    If you're here to ultimately discuss the subject matter of your argument, there are far easier ways. One can construct a fairly simple syllogism and then discuss the truth or otherwise of the premises. That is far easier than creating a modal argument, arguing over its validity across 3 or 4 threads, only to then have to discuss the same issues of how things actually work.
    If, however, you're here to discuss modal logic, and formal structures and proofs thereof, then you're clearly not going to get that here. So why persist?
  11. Speakpigeon Valued Senior Member

    Sorry, you're much too fluffy here and I can't parse. I just don't know what you mean.
    Copernicus was brought up in the dogma of Catholic Church that the Sun orbited the Earth. Given the technical means at the time, nobody could possibly prove either way. So, Copernicus definitely didn't know that it was the Earth that orbited the Sun.
    So, these are the facts.
    So, now, tell me it was obviously useless for Copernicus to make the following assumption: For all I, Copernicus, know, it may be that the Earth is orbiting the Sun.
    This, alone, is what came to be known as the Copernican Revolution.
    Sometimes, the ability to do "may" beats everything else that's available.
  12. Speakpigeon Valued Senior Member

    Both are equally valid.
    No. The validity of both arguments is equally certain.
    You're just confused about what the validity of a logical argument is.
    You should perhaps look it up on the Internet.
  13. Speakpigeon Valued Senior Member

    Yes, and if algebra is philosophy, then both arguments are philosophy, which is kind of algebra too: 1 + 1 = 2.
  14. Speakpigeon Valued Senior Member

    Why do you?
  15. James R Just this guy, you know? Staff Member


    I habitually use the words "may" and "might" differently to how you use them.

    These days, I try only to use the word "may" in the sense of having permission: "May I have another potato?" "Yes, you may."

    On the other hand, "might" indicates possibility, and says nothing about probability. "I might have another potato." There's no implication that it is very likely or very unlikely that I'll have another potato - just that there's a non-zero probability that I will have another one.

    When I want to talk about probability, I'll usually use the word explicitly: "I'll probably have another potato." [presumably there's rather more than a 50% chance that I will].

    On the other hand, it would be silly of me to insist that somebody else ought not to use the word "may" to indicate possibility, even though it rings my personal internal alarm bells every time somebody says "It may rain tomorrow." (The rain doesn't need your permission!)

    People will use words as people will use words, and so meanings change, not always for the better.

    Forgive me, therefore, for taking liberties with changing all your mays to mights. We agree on meaning, apparently, even though we disagree on how words ought to be used in our personal ideal worlds.

    I'm not wrong about the argument being weak.

    Sure. I voted in the poll. I voted "yes", before I wrote anything in the thread. If you're only concerned about validity, then yes, it looks valid enough to me. The soundness would depend very much on the identities of the A, B and C, in a specific application of the argument, I think.


    Okay. Once again, forgive me for being interested in whether the argument is useful for anything, when I should have concentrated solely on whether it is valid as a formal construct.

    Having read Yazata's post, forgive me if I'm not 100% convinced by your assertion that it is valid. I look forward to seeing your own, formal, demonstration of the validity of the argument.


    You'd need to identify the A, B and C in your premises before I could start to prove them false. As things stand, they are just place holders in a formal structure.

    Out of interest, which famous names have tried to demolish this particular argument, without success?
  16. Speakpigeon Valued Senior Member

    We both use them mostly in the same way but we each don't use them in the same way in different contexts, and I think may and might are a bit overworked given the number of very different contexts in which they are used, hence the confusion.
    Here, I am using "may" according to how it's used in modal logic, and indeed how it is used in ordinary language to talk about epistemological possibilities. So, I'm afraid "It may rain tomorrow" is a perfectly standard utterance because we're not talking about permission but epistemological possibility, i.e. "For all we know, it may rain tomorrow", using "might" instead if rain is possible but improbable. So, "may" here is just synonymous with "It is possible that".
    Yes, you're wrong. The argument is not weak. Maybe you mean that the conclusion is weak?
    But the conclusion may or may not be weak depending on the specific cases of substituting A, B and C, and since we're not talking about that, it doesn't mean anything to claim that the argument is weak.
    An argument is valid or not, sound or not, but it's just not weak. Unless anyone can refer me to what logic textbooks say on the weakness of an argument, because it's a new notion to me.
    Sorry, I don't have any famous name to offer but maybe it's a question of time. I could send it to anyone you may want to suggest.
    But I can tell you that there are a lot of very dogmatic people out there. People who are so adamant that the conscious mind cannot possibly determine what we do that although they accept the premises, which in itself is a real tour de force, they will nonetheless reject the conclusion.
    So, they have to claim that the argument is invalid... but they are all unable to prove it is invalid... because, well, the argument is valid.
    And when they understand the argument is valid, they will say is makes no sense. A new kind of dogmatic ideology.
    This is where our emotions can be shown to trump our sense of logic. Although, obviously, maybe it's not so much emotion as sheer stupidity.
  17. Baldeee Valued Senior Member

    The weakness of an argument is more related to inductive arguments.
    It is pretty much, afaik, a measure of how likely the conclusion is to be true.
    E.g. Jim is a teacher.
    All teachers like beer.
    Therefore Jim likes beer.
    This is a deductive argument, and valid.

    Jim is a teacher
    Most teachers like beer.
    Therefore Jim likes a beer.
    This is a strong inductive argument.
    If the second premise was that most teachers don't like beer then the conclusion as given would be weak.
    In inductive arguments you don't reach certainty, just likelihood of it being true.

    Your argument isn't weak, because it is a deductive argument, but the conclusion is weak as it stands.
    It is weak, in my view, precisely because of insufficient information to conclude anything other than non-zero probability.
    Accepting a premise that simply states a non-zero probability is not what I would consider a real tour de force.
    Anyone worth their salt will identify your conclusion as being pretty much worthless, even if valid, and wouldn't balk at considering it valid, irrespective of their view of the truth or otherwise of the premises.
    Just because you play the lottery doesn't mean you have the winning ticket.
    It means you have a chance.
    A non-zero probability.
    But at least with the lottery you can state the actual odds, unlike with the case of your argument.
  18. Speakpigeon Valued Senior Member

    No, the tour de force was to find a formulation of the first premise that even hardcore materialists couldn't dismiss except by claiming it doesn't make sense. So, most of them refrain from voting or commenting, or if they do they make a mess of presenting their argument.
    It is a tour de force also because the same logical structure can be used to make an argument about God to embarrasse dogmatic believers. However, if they used it themselves to embarrasse the other side, it would become really hard not to admit it is also embarrassing for their own side.
    I don't know about salt but some of them are preserved in brine.
  19. Yazata Valued Senior Member

    Then why did you write this (in post #19):

    "None of you can prove his assertion that the argument would be invalid. All anyone does here is merely assert it is invalid....

    ...I'm only interested whether you think it is valid or not and in proofs you can offer that it is not valid.
    Well, no proof here yet."

    I can't speak for anyone else, but as far as I'm concerned I don't know if your argument is valid. I'll even venture the opinion that it can't be proven valid or invalid as it stands, because it's too ambiguous. A big part of the question seems to revolve around how your first premise is interpreted.

    P1. For all we know, somebody's mind may be the state of a group of neuron's in this person's brain

    What logical function does the "for all we know" have? Is the premise about minds, states and groups of neurons? Or is it about what we know or think we know about them? The latter would introduce epistemic logic, a form of modal logic that's above my pay grade. And what are the words "may be" in p.1 doing? Are they introducing a modal possibility operator? If so, I'm unfamiliar with modal logic. Or is it simply acknowledging that the premise might be either T or F? Those kind of truth assignments don't require modal logic.

    How should we understand "somebody's mind"? The 'somebody's' can be taken care of with a variable and an existential quantifier, but 'mind' is more difficult. Are we talking about 'mind' as a single substantial object, are we talking about particular mental states, or about some kind of universal (the 'mental' that defines the set of all mental states)? Pretty clearly the mind-brain identity theory isn't intended to assert that mind in the sense of some Cartesian mind-substance, or a person's mind (in its entirety), or everything that qualifies as 'mental' is somehow identical to a particular state of a particular set of neurons. The theory is more plausible if we equate particular mental states with the states of particular sets of neurons (each of which will presumably be different). That might best be done with a set-theoretical mapping from the set of mind states to the set of neural states.

    So symbolizing your p.1 is going to result in a complicated formal expression, even if we omit your "for all we know" and "may be".

    Figuring out what might conceivably be derived from it might not be that simple a task.

    Perhaps you need to symbolize your argument in whatever way you prefer, and then try to prove (or at least convincingly argue) that it is indeed valid. That way you have to stick your neck out and we can take shots at you from the comfort of our own easy chairs.
    Last edited: Jan 22, 2019
  20. Speakpigeon Valued Senior Member

    You seem to be replying here to my other thread "Could our actions be decided by our conscious mind?" This can only add to the already excessive confusion and I'm not going therefore to address the contents of your post. Most of you are very undisciplined. The question is simple: Is the argument valid? Yes or no. Then, once you've answered that, you can discuss why it is or isn't invalid. Here most of you are discussing validity but soundness, weakness, what words mean etc.
    Those who want to discuss soundness would need to do it in the other thread on the conscious mind. I just put there a new argument to help you make up your mind.
  21. James R Just this guy, you know? Staff Member

    If you want to argue that it is valid, you ought to make the argument.

    Yazata has already done some work above that suggests that it might not be valid. I have yet to see anything from you in the way of a formal demonstration of validity, despite your repeated claim that this is the focus of your inquiries.

    I mean, I assume you've put some thought into this yourself. Perhaps you invented the argument. I agree with Yazata: it's time for you to put your own cards on the table, rather than saying "I say this is valid. Prove me wrong!" If this is all about logic, you ought to be equally able to prove yourself right, ought you not?
  22. Speakpigeon Valued Senior Member

    I ought not.
    Misrepresentation. It's not the focus of my enquiries and I never said it was.
    My focus has been expressed in the OP: Is this argument valid?
    I asked "Is this argument valid?". I didn't claim in the OP that it was and I didn't ask for proofs either way. I didn't claim to have a proof or that somebody had one. You're all making unwarranted assumptions. Here is a simple, straightforward argument, let's see how many people think it is valid like I do and how many people think otherwise. Some people, have been pretty aggressive in tone when claiming the argument invalid, and this leads to whether these people can support their categorical claim. All I have said myself is that the argument is valid on the face of it. But some people actually exhibited what they claimed was proof that the argument was invalid, essentially as a case of "undistributed middle". And all I had to do was to show that their purported proof was in fact junk, in that they had redacted the argument into another argument and effectively proved this different argument to suffer from undistributed middle. A pretty idiotic move and the guy is still coming up with the same junk. It is up to you to go through what I did say and make up your mind as to who is wrong. If you don't have the time to do it, fine, not my concern. And this is my thread, and I'm not going to accept that it is turned into something else. The question is simple: Is the argument valid? Yes, no, I don't know, the argument makes no sense. Simple. Well, yes, but people do what they like.
    I ought not.
    My view is that logic is ultimately intuitive. You look at the argument and, maybe, your intuition will tell you whether it's valid or not. I look at the argument and it's obvious to me the argument is valid. And I'm not the only one far from it. Further, I can show each of the few explanations articulated by posters here and elsewhere, to the effect that the argument would be invalid, to be themselves fatally flawed. Also, the few people I asked elsewhere who were certainly capable of producing a formal proof of invalidity didn't. So, valid on the face of it and not one proof to the contrary. That has to be good enough. I recommend it.
    However, this won't work if you don't understand what the argument says and there are many reasons why that could happen. And indeed, judging from the pretty dim comments people keep making here, it's no surprise they don't understand the argument to begin with. They don't even get near the logical structure of the argument, even though I tried to make it easier for them. Seems a lost cause.
  23. RainbowSingularity Valued Senior Member

    terms ?
    what parts of the brain are "unknown" ?

    logic ?

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