"Logical" objection to Empiricism?

Discussion in 'General Philosophy' started by Speakpigeon, May 31, 2018.

  1. Speakpigeon Registered Senior Member

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    Sure, if you think of logic as being nothing but formal logic. But that seems both tautological and false to me! If you think we can only discover the truth of a conclusion through using the kind of formal logic you've somehow learnt at school and only after having made explicit the relevant premises or axioms or assumptions then, sure.

    How do I know a logical truth is true? I think in broadly the same way as I know redness or pain when I experience it. Don't ask me how I do that, though.

    And I'm sure we all do it, though I accept I might be wrong on that!
    EB
     
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  3. iceaura Valued Senior Member

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    One frequently, as standard procedure, argues from appropriate premises that "if A then B". If the argument is (logically, as agreed) valid, it establishes "If A then B" logically. This is then knowledge, in most people's view - most people accept the conclusions of valid reasoning, logical truths, as information of a useful kind, as knowledge of the situation.
    Note that not even A, let alone B, need be specified in advance - A could be a complicated end product of a very long chain of reasoning from whatever the premises of the whole situation were, and B of course is established by validity of the argument from A.

    Example: after a long chain of reasoning the philosopher of natural science concludes that if basement centipedes grow to be the size of wolfhounds then they seriously endanger children. Suppose careful inspection of his reasoning finds it impeccable: given his premises, his conclusion does follow - a logical truth.

    And we see that is a bit of knowledge - we do know that if A then B, here. It can even be useful knowledge, as similar conclusions of valid reasoning have been in the past - say: leading to the realization that there was an absence to explain (large predatory centipedes endangering large mammals) and focusing attention on matters that would in fact explain the absence (one or more of his premises is not met in the physical world).
     
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  5. Michael 345 Looking for Bali in Nov Valued Senior Member

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    Bridge can never get you to the other side of the river

    You are always there

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  7. Speakpigeon Registered Senior Member

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    I don't think you quite understood the OP. It seems we're not talking at all about the same thing here.

    If I understand what you say, you are talking about a situation where B has been observed to be true whenever A has been observed to be true, which leads you to conclude that the implication A ⇒ B is true. This is your standard empirical method. And if you ever came to observe even one case of B being false while A would be true, you would then discard the implication A ⇒ B as being false, again standard procedure, in fact not only of scientists but of every reasonable person on earth.

    Obviously, in this context, establishing the truth of the premise A is absolutely necessary. In science, this will be done presumably by careful observation and, if necessary to that end, by carrying out an experiment or using an experimental setup.

    That's all interesting but I already had a fairly good idea of how the scientific method works and that's just all fine with me. So your point is all well and good but apparently entirely beside the point. I'm talking about logical truths, not about the scientific method. And in this case, I fail to see where I would need to use any premise.

    Unless you can demonstrate that we tell logical truths using the same modus operandi as you sort of described in your post.

    Now, I'd be very interested to see that because if I'm doing anything like this, I would be doing it while being totally unaware I'm doing it, even as I'm trying to find out how I'm doing it. It would truly come as a major revelation to me, somewhat like the sea opening up for Moïse to cross.

    It would be a revelation for me but I think it would be a revelation for all those people who do understand what a logical truth is, including quite a few bright minds in the long history of philosophy. They'll be watching this space very carefully I'm sure from wherever in Heaven they must be brooding now.
    EB
     
  8. Speakpigeon Registered Senior Member

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    Very possibly, in which case being always there must be assessed fairly as being very useful.

    Still, in my experience, logical conclusions are things you have to get to and the only way to get to them is by using logic.

    If not, then it would be something, true or not, you just happen to believe.

    So maybe logic here is something that gives you confidence that what you believe is indeed true.
    EB
     
  9. iceaura Valued Senior Member

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    Nothing in my post suggests anything of the kind. My example, for example, is of the opposite situation - where neither A nor B has been observed, and neither one is thought to be at all likely or even possible, but "If A then B" has been validly reasoned from premises.

    And that valid logical reasoning, concluding in a logical truth, produced thereby knowledge - something then known and usefully so, namely "If A then B".

    And some of the use of this kind of knowledge is in empirical investigation - scientific research. It instigates and inspires and guides and analyzes and aids in comprehension.
     
    Last edited: Jun 2, 2018
  10. Michael 345 Looking for Bali in Nov Valued Senior Member

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    Possible?

    No idea why it would be useful???

    However in what way in being on one side of a river not "always" being on the other side?

    True story

    Two blondes walking in parallel either side of a river
    One yells to the other
    "How do I get to the other side?"
    Other blonde looks across and yells back
    "Your already there"

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  11. Speakpigeon Registered Senior Member

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    Good.

    If you say so.
    EB
     
  12. Michael 345 Looking for Bali in Nov Valued Senior Member

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    Humpty Dumpty strikes again

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  13. sideshowbob Sorry, wrong number. Valued Senior Member

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    How about giving an example of a logical truth?
     
  14. Speakpigeon Registered Senior Member

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    318
    Here is a nice one and easy enough: ((A ⇒ C) ∧ (B ⇒ C)) ⇒ ((A ∨ B) ⇒ C)

    Same thing in good English: ((A ⇒ C) and (B ⇒ C)) ⇒ ((A or B) ⇒ C)

    If you look at it analytically, i.e. using your linguistic skills to analyse the formula, you may be tempted to say there's a mistake or that the formula doesn't say quite as much as it could say. Then again, if you let your brain explains things to you, you should see it works just fine. In other words, because it may not be so easy analytically for the untrained, it should be easier for you to use your intuition than to plod through a formal proof. Best way to get convinced, I guess.

    This one is more basic: ((A ⇒ B) and (B ⇒ C)) ⇒ (A ⇒ C).
    EB
     
  15. Speakpigeon Registered Senior Member

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    318
    I can't on my own make the conversation from both sides of the river.
    EB
     
  16. sideshowbob Sorry, wrong number. Valued Senior Member

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    So what use is a logical truth unless some part of it is connected to reality?
     
  17. Speakpigeon Registered Senior Member

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    The fundamental reason for the usefulness of logical truths is that they are things we know. Personally, I am certain that anything you know is useful. The only limitation is in yourself, i.e. whether you'll find out how to use what you know.

    More specifically, I would expect knowning logical truths to help prove mathematical theorems and thereby simplify the mathematics of science in particular. I am no mathematician, so I don't know if logical truths are used in practice or how much. But I think they must be or could be.

    Philosophers seem to have very different views on the question of the connection to reality. As I see it, logical truths are about reality only in the sense that they are about our models of the physical world, about our mathematical models of the world but also and more fundamentally about our mind as a model of the world around us. So, as such, I would say they have to be very useful.

    Sorry I can't give specific examples but that's not really my concern here and this point has not bearing on the question I put in the OP...

    I hope that will be good enough for you.
    EB
     
  18. river

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    11,058
    True

    But reason is based on the accumulation of knowledge .

    Without knowledge how would you recognise a logical truth ?
     
  19. river

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    11,058
    The logical objection to empiricism is not logic so much as it is , the objective mind of the interpreter of the empirical information .

    Although this hints at a logic .
     
  20. Forceman May the force be with you Registered Senior Member

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    An objection to truth is not always a simple conjecture. The top of the list makes known logic a truth so it seems like history is always telling the truth : like with i or x that i can equal to x or ix is always a joined sentence of a simple truth that many logics are imaginary. This makes an axis of many lines joined together put into focus empiricism as just a pivotal argument for whether or not lines can be formed again and again without a line or axis but with imagination, that seems more like an empirical argument that sinx + a value is core to the aligned value and that all federations of morality and a concept is more like an afternoon -a particular one with push and pull: like an evening. To look at everything with logic would then be a b to the sinx and then a value then puts a signed in afternoon more like plural many nights and many nights out of a month leads logic back to b as in a = sinx or sinx + C and that puts a value into the second core than the valuable core. Sinx + a can then make a value more special and the lesser value is then more of sinx then a dark night then a lighted night. The truth would be that it's night and a logical conjecture would be the calculation of wind or better- the calculation of temperature over the roofs.
     

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