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Are there propositions

  1. Mar 14, 2005 #1
    Hello, here's a question. Looking for insights. More to do with the Platonist / Naturalist divide, but not necessarily limited to that.

    So.... Are there propositions? :biggrin:
     
  2. jcsd
  3. Mar 14, 2005 #2

    HallsofIvy

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    Define "proposition". If you can, then they exist!
     
  4. Mar 15, 2005 #3

    honestrosewater

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    Do you say this assuming that a definition is itself a proposition? It surely isn't true in general that if a definition of X exists, X exists- unless we have different ideas of what a definition is.

    drunkenfool,
    A proposition is usually defined in such a way that "propositions don't exist" is itself a proposition. Do you have a different definition in mind?
     
  5. Mar 15, 2005 #4
    drunkenfool: So.... Are there propositions?

    Yes. Propositions are declarative sentences which are either true or false.
    That is, they are meaningful statements.
     
  6. Mar 15, 2005 #5
    Yes they do exist. I am the proof of it. I am predisposed to be right on most of the topics compared to HomoSapiens.
     
  7. Mar 15, 2005 #6
    The question is asked more in the sense of:

    do propositions tangibly exist? do they represent some sort of metaphysical certainty? or are they merely concepts employed to help us communicate?

    I have an acquaintance who is an ardent Platonist and adamantly refuses to accept that human logic is anything less than the imperfect representation of some sort of pure / perfect logic that exists.

    In this context, propositions are then the embodiment of these perfect ideas in a tangible form.

    Personally, I see no need to believe in perfection or some sort of Forms for logic and its development to make sense.

    Am I off my own topic?
     
  8. Mar 15, 2005 #7

    Tom Mattson

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    :rofl:

    They don't tangibly exist. It's not as if you can stub your toe on a proposition! But they do exist conceptually, as abstract objects. Existence proofs are typically done by construction, so all you have to do is cite an example of a proposition, and there you have it.
     
  9. Mar 15, 2005 #8

    honestrosewater

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    Someone just started a similar discussion in the Philosophy of Science and Mathematics forum, and we've had the discussion there before; selfAdjoint pretty much gave my answer.
    I would put the most emphasis on the process of abstraction. I think Platonic Forms exist as concepts, specifically, as the ultimate abstractions, the most general generalities, but I don't see any reason to think they are anything more.
     
  10. Mar 15, 2005 #9

    honestrosewater

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    That's funny. I would count writing and speech as tangible forms. For some reason, I think specifically of copyright laws that require a creative work to be in tangible form in order to be eligible for copyright protection. Here, written or spoken (recorded) form is tangible. Perhaps you're being clever and making a distinction between a proposition and one of its tangible forms.?
     
  11. Mar 16, 2005 #10
    I disagree with the assertion that they are Platonic entities. In fact, I see no reason to allow for Platonic entities. We can do quite well without their existence.

    In terms of abstraction etc. I take a very materialistic view to this. Though my entire argument lies on how someone defines reality.. so....

    anyhow. if we can accept that "our" reality.. or the reality that can have any meaning to us, is solely what we can sense or tangify. Then ideas and concepts arise from essentially the parameterization of the universe. Which is in effect the result of the desire to be able to communicate...

    im sorry if the above isn't particularly coherent. but alas, it is late and i'm just a drunken fool :P.
     
  12. Mar 16, 2005 #11

    Tom Mattson

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    So do I, but I don't consider "propositions" to be identical to any subset of either writing or speech. In my usage, propositions are that which are conveyed by physical means, not the physical means themselves.

    It's not me, it's my logic book. I learned the subject from Logic by Robert Baum, and so I use his definitions, which are...

    and...

     
  13. Mar 16, 2005 #12

    honestrosewater

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    How so? I am speaking of abstraction as a thought process.
    Eh, I'm sleep deprived myself, but that's nothing new. :yuck:
     
  14. Mar 16, 2005 #13

    honestrosewater

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    Okay, I should have made those distinctions earlier. But a proposition still contains information and so would, in some sense, be tangible, no?
     
  15. Mar 16, 2005 #14

    Tom Mattson

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    I suppose that depends on how metaphysical you want to get. I regard causal efficacy in the physical world as a necessary condition for tangibility. So there is a person who knows a bit of information, which we can call a proposition. That knowledge corresponds to a (physical) brain state that would not exist if the information were not there. So I suppose one could argue for the causal efficacy (and afterwards tangibility) of propositions. But not wanting to get into the Mind-Body problem, I just side with Baum and say that propositions belong to the class of abstract objects, just as mathematical objects do. Besides, causal inefficacy is not the only criterion for being classed as an abstract object. There is also a non-spatiality (that is, non-existence within our physical space) criterion. And as far as I know, no one can point to the location of a proposition.
     
    Last edited: Mar 16, 2005
  16. Mar 16, 2005 #15

    honestrosewater

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    Tom,
    Good points; I'll drop it. I'm actually trying to avoid the metaphysical for a while.
     
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