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A Meta-Metaphysical Question

  1. Nov 27, 2004 #1
    My question is - why are metaphysical questions undecidable?

    Don't feel obliged to read any more of this before answering, it's a bit long, but I wanted to put the question in some sort of context and so focus any discussion, and also see what objections are made to my thoughts on the issues.

    Metaphysical questions are defined as coming ‘after’ Physics, or as having answers that lie ‘beyond’ Nature. Now, if such questions were simply beyond the reach of science to answer then we could argue that the existence and intractability of these questions is evidence for the inadequacy of the scientific method, the falsity of the ‘scientific view’, or the incoherence of the beliefs of many scientists. This is not an uncommon argument.

    However metaphysical questions are not simply undecidable in this sense. They are undecidable in a formal mathematical sense. That is, all reasonable answers to a metaphysical question give rise to contradictions within the formal systems of reasoning that give rise to the question. That is to say, metaphysical questions cannot be decided within the system of reasoning used by the person who is asking the question. This is for the same reasons that ‘Gödel-sentences’ cannot be decided within the formal systems in which they arise.

    What this means is that if it were found to be the case that either answer to a metaphysical question were true or false then this would contradict our reason and call into question our whole notion of logic and illogic, consistency and inconsistency. It would mean that the explanation of our existence contradicts our reason. This presents us with a stark choice of view. Either we must conclude that metaphysical questions are formally undecidable or that the true explanation for the existence of our universe contradicts reason.

    This dilemma can be illustrated by looking at the question ‘did the universe arise from something or nothing?’ This is a pretty simple question, and it appears to be a perfectly reasonable and meaningful one. On the surface there seems no reason why it should be undecidable in principle.

    Yet it is. This simple little question has baffled thinkers for millenia. Both answers to it give rise to logical contradictions, so neither answer can be correct according to common sense. No reasonable answer to it is given anywhere in western metaphysics or the scientific literature. It is such an impossible question that some philosophers have argued that it's not a question at all.

    It doesn’t take much analysis to uncover the paradoxes that appear if we try to answer this question by deductive reasoning. If the universe arose from something that existed already then clearly this just begs the question. What did this ‘something that already existed’ itself arise from, something or nothing? And if spacetime comes into existence with this universe, as most scientists seem to believe, then how can something have existed ‘before’ this universe? In what sense can something be said to ‘exist’ if it has no extension in either time or space?

    Perhaps some kind of God predated the universe. But if so where did He, She or It appear from? To appeal to a divine miracle begs the question again. Why isn’t there just nothing at all?

    Perhaps philosophical idealism is true, in which case consciousness is fundamental and we are all figments of our own imagination. But this doesn’t help. Whose imagination is doing this imagining? If, as in Berkeley’s idealism, to be is to be perceived and to perceive is to be, then it is not possible for the perceiver to exist before the perceived, nor for the perceived to exist before the perceiver, nor possible for them to come into existence at the same time except by coincidence. And what did this perceiving or perceived entity arise from?

    Does ex nihilo creation make sense? Cosmologist Alan Guth has conjectured that it might be possible, and even necessary, to devise a theory of how the universe comes into being from nothing. However, and perhaps this is a just matter of opinion, there seems to be an air of desperation about the idea, and I can't help feeling that any such theory would be bound to contradict reason at some point, mine anyway.

    It’s hopeless. Metaphysical questions are always questions about ultimate reality, what it is that lies outside the cave, behind the world of appearances, and they have no reasonable answers. There are no exceptions to this rule for this is how we define 'metaphysical questions'.

    I’ve run through all this before asking my question because sometimes metaphysical questions are thought to be simply undecidable by physics, when in fact they are undecidable in a much stronger sense than this. One of the most secure pieces of knowledge about reality that we have is that metaphysical questions, questions about what is ultimately real or ultimately true, have no reasonable answers, cannot be answered without causing logical contradictions.

    The situation we find ourselves in is one in which either the existence of the universe contradicts reason, or all questions about what is ultimate and fundamental, ‘ultimate reality’ if you like, are undecidable by reason. If this is the case then there seem to be only three possible views as to why this might be the case.

    The first possiblility, or possible view, is that it is not true to say that we and our universe arise from something or nothing. In this view the universe arises from ‘something’ undefinable that cannot be properly characterised as being either something or nothing, and the 'something-nothing' question, and other such questions about reality, embody false assumptions and therefore cannot be answered non-contradictorily.

    The second possibility is that the true explanation for the existence of ourselves and our universe makes complete sense, is perfectly reasonable, is self-consistent in a formal mathematical sense, but that for some reason it does not appear to be so to human beings. Equivalently, the explanation is logically consistent, but in a way that is beyond the ability of human reasoning to understand.

    The third possibility is that we and our universe exist for reasons that would, if we knew them, contradict our reason. This seems unlikely to me, but I notice that respected science-writer Paul Davies speculates on this possibility in his book 'The Mind of God'.

    To me these seem to be the only three possibilities, and all explanations of the universe seem in the end to rest on one of these three views. However, I'm sure not everyone will agree (I hope not anyway).

    My question is then, (and sorry for the length of it), why are metaphysical questions undecidable? And would you agree that the three answers to it I've outlined above are the only possibilities?
    Last edited: Nov 28, 2004
  2. jcsd
  3. Nov 28, 2004 #2
    Is it possible that there's another dimension, more akin to the realm of thought let's say, which gave rise to the material dimension?
  4. Nov 29, 2004 #3
    I'd say very possible. But why would this make metaphysical questions undecidable?

    By the way, sorry about the ridiculously long question. I can see now that I wrote far too much, but I can't get back to it to delete any of it. Is there a time limit on edits?
    Last edited: Nov 29, 2004
  5. Nov 29, 2004 #4
    "If the conclusion is absurd and the logic is correct then the premises must be re-examined." The obvious logical answer is that at least one or our assumed premises must be wrong. IMHO the most likely candidates are that the universe must have a beginning, must have arisen at all much less from something or from nothing. The other is that the universe is all that there is.

    If there is an "Ultimate Reality" of which the universe is part then the Ultimate reality must either have arisen or be eternal. This again begs the question as you said; so, if there must be an answer then the answer must be that something is eternal. As hard as that is to except it is more logical or reasonable than something haven arisen spontaneously without reason or cause from nothing.

    To answer your question, I would say that all reasonable metaphysical questions have reasonable answers; but, as they are metaphysical questions so are the answers; that is, outside of or beyond physics.

    It is not reasonable to expect a physical answer that can be empirically tested and proven to a metaphysical question. Nor is it reasonable to apply physical, scientific methodology to a metaphysical question.

    I fully realize that this is not a satisfactory answer to most physicalist; but, would one reasonable use mechanical or carpentry tools to bake a cake? Physics, science and logic are after all only tools that we use to learn, know and reason. They, like all tools, are useless even harmful when misapplied.

    When asking metaphysical questions we must expect, look for and accept metaphysical answers. This is perfectly logical, reasonable and acceptable to me. This is, however, totally illogical, unreasonable and unacceptable to most physicalist. This says something about physicalist but I will refrain from saying any more as I do not want to start that old fight again.
  6. Nov 30, 2004 #5
    I agree with a lot of that. But I feel you've slightly dodged the question. Certainly there can be no scientific answers to metaphysical questions (not unless we decide to redefine science anyway) but why are there no answers at all? This is why I wrote so much at the start, to get away from the idea that questions about reality are simply beyond science. That isn't too hard to live with, but the situation is worse than that. Why is it that, according to reason, it is impossible for any answer to these questions to ever be given?
  7. Nov 30, 2004 #6
    You will have to define what you mean by reason. If you mean formal logical reasoning then the answer to your question is that most of the questions do not lend themselves to formal logical reasoning as there is no inductive or deductive proofs. That is why it is metaphysics.

    There is no way that the existence of anything can be proven empirically in metaphysics because there is no empirical reasoning in metaphysics. If there is empirical reasoning then it is physics. Logic can be used but can only be used if we make assumptions that can not be proved.

    In other words, to answer your question directly, if there are proven answers it isn't metaphysics. If it is metaphysics then there are no provable or reasonable answers without prior unprovable assumptions.

    It is the nature of the beast, a built in catch 22. If there are reasonable answers it ain't metaphysics. If there are no reasonable answers then it is metaphysics.

    The wonderful thing about metaphysics is that it is an area of pure speculation. We are free to make assumptions of any sort and go from there and there is no end, no conclusion, no restrictions and no rules. Given the beginning assumptions we should use the rules of reason and logic but that doesn't mean that there is any satisfactory conclusion to be made or even possible. If you want answers stick with mathematics or formal logic. Even physics has more questions than answers and the boundary between physics and metaphysics is blurring more and more the more we learn.
  8. Nov 30, 2004 #7


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    Metaphysical questions have traditionally been about either being or knowledge. Those which are about knowledge risk the trap of self reference, which could lead to undecidability in the formal sense (but I am not aware of any proof that this is so). Questions about being turn on individual definitions of being, which is vague, and entails the definition of non-being, which is even more vague than being. So I don't think philosophers' sayings about being can be anything more than an art form.
  9. Nov 30, 2004 #8

    The human brain may never be able to understand and answer metaphysical questions because it is bi-polar in its nature of thinking. It can only take a measurement from a position of analyzing opposite ends, based on an unchanging set of laws. Why we may never know where the universe came from, what matter is made of, or what is the mind matter relationship is, demands the question, is there something outside of physical systems? There may be but as long as it is inside of a body, analyzing the outside, we will not know what it really is, nor know the answers to which it is related. If there is a after life maybe this non-physical being will be able to analyze a holistic metaphysical existence and know those answers.
  10. Dec 1, 2004 #9
    Yes, that is what I mean by 'reason'.

    It seems true that these questions do not lend themselves to inductive or deductive solutions, the question is why this is so.

    It's not correct to say that metaphysics is not empirical. The facts about the world that we know empirically are the basis for metaphysical speculation, and so are all the facts of physics. One cannot speculate metaphysically without the knowledge gained through ones sense, and it would be odd to ignore the empirically confirmed findings of physicists. These days most philosophers are pretty knowledgable about physics, they have to be.

    Yes, there is no other form of formal logic but the construction of systems based on unproven assumptions. But you seem to be saying that formal logic cannot be used in metaphysics, which I cannot agree with. It is formal logic that tells us that metaphysical questions are undecidable.

    I agree that there are no provable or reasonable answers to these questions, whether or not we make assumptions. Metaphysical questions just do not have reasonable answers. But my question was not about whether this is so, but why.

    Here I very much disagree. Doing metaphysics isn't an excuse to give up rationality.

    Yes, but why not? The questions are simple enough, why can't they be answered? For example, if materialism is true (is the case) then why can't we falsify idealism. What is it about 'reality' that prohibits us from deciding these quetions one way or the other, even if only in principle. Whether we can prove things one way or the other is not the point here. These questions cannot be answered even hypothetically without contradiction.

    Yes, I have no intention of giving up formal logic, and see no need to. I would say that formal logic suggests that metaphysical questions cannot be answered because none of their answers are correct, not because there's something logically inconsistent about our existence.
  11. Dec 1, 2004 #10
    They do, as I said. It is just that the premises and/or conclusions are not acceptable to most, primarily because the premises are speculative, subjective and not provable. For example: The universe is eternal or had a beginning. We cannot prove either way but once we accept that it had a beginning we can argue what that beginning was, the Big Bang or Created.
    In ether case it had to come from somewhere or something or from nothing.
    Somewhere or some hing brings another questions of where that something came from etc. This is no answer so that leaves the choice of either the universe is eternal or that from which it came is eternal. That is a valid reasonable conclusion and an answer. Is it acceptable? Most would say, no.
    Yet it is a reasonable logical answer reached by reason and logic once a speculative premise is agreed upon for the sake of the argument. It is a classical method of deductive reasoning via reductio ad absurdum.

    The word "empirical" mean to experience, measure or test. Most metaphysical questions cannot be measured or tested. That leaves experience. I and others report that we have personally experienced God in our lives. It is consistent, reproducible, verifiable, and supported by similar claims from many others. That is empirical evidence that God exists and is active in our lives. Is this scientific proof? Do you accept this as proof of the existence of God? No, of course not. Nor would (or did) I unless and until I experienced it myself. That is metaphysics. The question of the existence of God is as metaphysical as it get. We have evidence that is consistent, verifiable, reproduce able and substantiated but it is not acceptable scientific proof. Why? Because that kind of experience is not considered empirical or scientific. It is meta physical. Yet it is as I said a metaphysical answer to a metaphysical question.

    No, I am not saying that at all. I am saying just the opposite; however, regardless of the quality of the logic or reasoning it is neither acceptable to most nor is is scientific because it is a metaphysical answer to a metaphysical question regardless of the validity of the process or conclusion because the premises must be by their very nature metaphysical speculation and therefore unprovable.

    I do not agree with any of this statement; nor; is is what I said in my previous or this post. Just the opposite is true in my opinion. All metaphysical questions have reasonable metaphysical answers They just don't have reasonable scientific, physical answers. Why? BECAUSE THEY AIN'T SCIENTIFIC, PHYSICAL QUESTIONS! Do you get reasonable mathematical answers when answering a logic question? No. Why? Because logic isn't mathematics.

    No it isn't and I never said it was. It is a reason (not excuse) to think outside the very limited scientific box. If is isn't science, then how does one ask these questions at all unless one delves into the metaphysical? Once we have dove in why do you insist one looking for nice neat wrapped up in the the box scientific answers? All the answers are right there all around you and perfectly reasonable and acceptable withing the realm of metaphysics which is an important part of our reality whether you like it or not. If it were not real then and rational then how could you ask a real rational question about it in the first place?

    Answer your own question using logic. If we cannot falsify idealism them idealism must be real. If idealism is real then materialism cannot be all there is, cannot be all inclusive and therefore must not be the case, the whole case and nothing but the case. If Idealism and Materialism are real then they both must be part of reality. Simple!

    There is no contradiction. The material world, universe exists. This cannot be denied. The non-material, subjective, ideal, metaphysical world also exists. This too cannot be denied. Intent, purpose, feeling, awareness and consciousness exist, are real, cannot be denied and cannot be completely satisfactorily explained by pure materialism. Where Materialism make its fatal flaw is that it maintains that materialism is all inclusive to the exclusion of everything else. Nothing that is not material or of the material world exists or can be real. This in itself is a contradiction because Materialism is an idea, a philosophy that is purely subjective. The contradiction is contained within Materialism itself not between the material and ideal realms of reality. They are both parts of the one reality and not mutually exclusive at all but merely different aspects of the same, the one reality.

    This is not correct. I would say that formal logic (itself an ideal concept) suggests that metaphysical questions cannot give material answerers because it isn't a material subject. There is nothing inconsistent about our existence or about all of reality. It is just that there is more to reality than the physical, material and Materialism.
    Last edited: Dec 1, 2004
  12. Dec 1, 2004 #11
    But we do know that everything came from or was caused by a/the eternal universal mind by whatever name or term you choose to use. Is it still metaphysics? Yes because our empirical evidence though overwhelming is not deemed scientific, material empirical evidence and therefore is not physical but metaphysical. Go figure. Oh well, so much for the mythical open, inquisitive, scientific mind.

    Remember back in the good old days when the world was flat and the earth was motionless at the center of the universe. We used to burn, hang and torture open minded inquisitive scientist. We must have got all of them, huh? Or at least taught them a lesson.
    Of course now our scientist figuratively do the same thing to all of those who think outside of their neat little boxes and text books. I guess we have nobody to blame but ourselves.
  13. Dec 1, 2004 #12


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    This is silly. Scientists have defined their enterprize to be based on objective checkable evidence; nullius in verbo. To slam them for not accepting your subjective, uncheckable evidence is like critcising a horse for not being a cow.

    Scientists are truly open minded as a culture for things that can be checked (pace Kuhn, who distorts history to make his points). If the scientists gave up this voluntary restriction on the evidence they will take seriously, then they wouldn't be any better than the wooly dreamers and charlatans who have infested the world since the stone age, and produced nothing that can be generally used.
  14. Dec 1, 2004 #13
    I'm sure I posted an answer here along the lines of it is not undecideable, we just can't reach consensus on an answer.

    Subjective interpretations would have you make up your own answers and be happy with them cos they are right for you as when it comes right down to it all there is is YOU.

    So what happened to my posts ???
  15. Dec 1, 2004 #14

    Tom Mattson

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    I deleted your posts because they were off-topic. You are using a colloquial definition of the word "undecidable", when Canute explained exactly what he meant by the term in his opening post:

  16. Dec 1, 2004 #15
    well actuallyTom

    However metaphysical questions are not simply undecidable in this sense.

    The implication is there are 2 definitions of the sense in which he framed his question. In line with that my answer is perfectly on point.

    I think it is an assumption on his part that there is no answer. Just because he doesn't have an answer doesn't mean the rest of us don't.
  17. Dec 1, 2004 #16
    ...perhaps he should define what the term undecidable means or seeing as how you obviously have a handle on it's meaning then maybe you could enlighten me

    I can't seem to find an accurate definiton let alone a colloquial one...
  18. Dec 1, 2004 #17

    Tom Mattson

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    Yes, and your responses don't refer to either definition. By one definition of "undecidable", he is saying that the answers to metaphysical questions cannot be decisively found because they cannot be found scientifically. But that's not what the thread is about. This thread is about formal undecidability, as that undecidability referred to in Goedel's theorem. Your answer is not "on point" with this at all.

    It isn't an assumption on his part. It's not a matter of opinion, it's a matter of logic.

    I repeat my previous statement: Let's stay on topic, please.
  19. Dec 1, 2004 #18

    Tom Mattson

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    He did say what he meant by it. I quoted the passage.

    If you are still unclear, then read this page, and follow the links therein:

    Undecidable, from MathWorld

    That's what he's talking about.
  20. Dec 1, 2004 #19
    OK then...

    how about the system of reasoning and logic aren't all they are cracked up to be and one should be reluctant to rely on them solely to provide answers that cater for everybody.

    I don't think they are "undecideable" . I think it is Canute that is undecided about his answers as the reasoning he is using is faulty.
  21. Dec 1, 2004 #20
    BTW thanks for the definition...
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