• Bartricks
    6k
    I think we can. I don't think there are any necessary truths or any necessary existents (I believe this for two reasons, a) I believe God exists and that if God exists there are no necessary existents because God, being all powerful, can destroy everything if he so wishes and b) I can't fathom what 'necessity' actually is).

    I think there's just what's true and what's not. And when it comes to the laws of logic - which are often said to be necessary - I think we can just take them to be instructions without having to take them to be describing any 'necessary' feature of the universe.

    Take this argument:

    1. if P, then Q
    2. P
    3. therefore Q

    We all agree that it is valid, I hope. But we can express this perfectly adequately, it seems to me, just by saying that if those premises are true, then the conclusion will be as well. However, most will say that if the premises are true, then the conclusion 'must' be true as well. I think that 'must' adds nothing. We can simply dispense with it.

    Necessity, I think, is a fiction. There is no necessity in the world. There's just what's true and we have a tool - our reason - that we can use to find out what's true and what's not. What I suggest we do, then, is simply try and stop saying 'must' and 'always' and 'never' and see what happens.
  • jgill
    3.6k
    Will be = must ? Too deep for me.
  • TheMadFool
    13.8k
    For what you say to be of any significance it must be true i.e. your claim must be a necessary truth.

    The whole point of logical argumentation is to prove necessary truths. Either you're arguing for the position that there are no necessary truth or you're not. If the former then you're contradicting yourself; if the latter, why should we accept your views?
  • Bartricks
    6k
    I don't think that's what 'will be' means - for instance, if I say "I will be there" then I am not saying that it is a necessary truth that I will be there, but just expressing my commitment to be there.
  • Bartricks
    6k
    that's question begging. You've just stipulated that the whole point of logic is to 'prove necessary truths'. I am pointing out the redundancy of the word 'necessary'.

    You ask why should you accept my views - well, if they're true that gives you reason to accept them, no? Why do they have to be necessary truths?

    I mean, everyone accepts there are tons and tons of contingent truths - do you alone disbelieve them all?
  • DingoJones
    2.8k
    MadFool is right, the question contradicts itself.
    Its the same thing as in the omniscience thread, you aren’t grasping the law of non-contradiction. It precludes both of your arguments in the two threads.
    You said you do not understand what “necessity actually is”, can you elaborate on that?
  • Banno
    23.4k
    In any possible world, a triangle will have three sides.

    Hence, it is necessarily true that a triangle has three sides.

    And it follows that there is at least one necessary truth.

    The thing I drew in the sand has three sides, but in some possible world, it has four.

    Therefore there is at least one truth that is not necessary.

    So your premiss is wrong.


    You might find something useful in the SEP Modal Logic article.
  • Wayfarer
    20.8k
    If there are no necessary truths, then nothing you can say is necessarily true.
  • Bartricks
    6k
    How does dispensing with necessity generate a contradiction? Because you say so?

    Perhaps you think I reject the law of non contradiction. No. I think it is true.

    Perhaps you think that's contradictory. No, for I can express the law without invoking necessity: a true proposition is not also false. There.

    Something doesn't 'have' to be true in order to be true. It's true that it is raining. That's not a necessary truth, but it's no less true for that.

    As for not knowing what necessity is, I cannot comprehend what the word 'necessarily' corresponds to when it is added to true. So, a 'true' proposition is one that corresponds to the facts. What does a necessarily true one do?
  • Metaphysician Undercover
    12.5k

    So you are replacing "must be" with "will be". I assume that "will" implies a free will, which is distinct from "must" which implies a determinist necessity. Are you saying that the logical process is a free will choice, to choose the logical conclusion, rather than that the logical conclusion is forced by some sort of determinist necessity?
  • Bartricks
    6k
    That's obviously question begging. Triangles have three sides. That's all you need to say.
    Saying 'they have three sides in all possible worlds' is just another way of saying 'it is a necessary truth that triangles have three sides'. It's not a case or demonstration of the fact anymore thansaying 'triangles necessarily have three sides' in Latin would be.

    Be assured that I am as certain as you are that triangles have three sides. I just don't think it is a necessary truth. But I'll be just as good at recognizing triangles as you
  • Bartricks
    6k
    Yes, I know. I'll settle for it being true.
  • Bartricks
    6k
    Not sure I follow.
    I reject determinism because the notion invokes necessity. But that leaves open whether we have free will or not (which is what one would expect if necessity is doing no real work) as it leaves open whether we are originating causes of our decisions or mere links in a chain. It's the latter that seems to preclude our being free.
  • Heracloitus
    487
    Take this argument:

    1. if P, then Q
    2. P
    3. therefore Q
    Bartricks

    1. If Bob is a bachelor, then he is unmarried
    2. Bob is a bachelor
    3. Therefore: Bob is unmarried

    The conclusion necessarily follows. You can't have true premises and a false conclusion.
  • Isaac
    10.3k
    You can't have true premises and a false conclusion.emancipate

    1. If Bob is a bachelor, then he is unmarried
    2. Bob is a bachelor
    3. Therefore: Bob is married

    There you go. Turns out you can.
  • Arne
    815
    your whole argument is premised upon the necessity of the law of non-contradiction.

    Interesting idea though.
  • Arne
    815
    There you go. Turns out you can.Isaac

    Excellent. :-)
  • Heracloitus
    487
    Well sure, you can do that if you don't care about maintaining logical validity.
  • unenlightened
    8.8k
    There you go. Turns out you can.Isaac

    ... if you don't care about maintaining logical validity.emancipate


    So necessity has a scope in the domain of language that extends to valid reasoning. It does not extend to the world at large, because language and logic cannot order the world about. The world does what it pleases, and language tries to follow and describe. Logic and necessity keeps language aligned with itself.

    If the op is simply saying that necessity does not constrain the world, then I agree. But if he is saying that it does not constrain sensible talk, then i disagree.
  • Bartricks
    6k
    The conclusion follows, yes. Which is just another way of saying that it will be true if the premises are.

    You're just adding - entirely needlessly - that it will be necessarily true.

    I can do something similar. Here: I stipulate that a valid argument is one that, if the premises are true then the conclusion is Potter true.

    What's 'Potter' true? you may ask. Well, a proposition is Potter true when it is true in all Puddleduck worlds.

    Think that's nonsense? Think adding a special category of 'potter' truths to the realm of truth adds nothing? No, reject Potter truths and you reject the validity of this argument:

    1. If p, then q
    2. P
    3.therefore q.

    What's that? You say you 'don't' reject it's validity you just reject that the conclusion is 'potter' true rather than just true? But no, I just told you that 'valid' means 'is Potter true if the premises are'

    So I will do you a deal - I will accept that there are necessary truths if you will accept that there are Potter truths.
  • Bartricks
    6k
    no it isn't.
    I think that if a proposition is true, then it will not also be false.
    You agree, I take it?
  • Arne
    815
    and that is called the law of non-contradiction. And it is necessary to your entire argument.

    So you have refuted your own argument.
  • Arne
    815
    I think that if a proposition is true, then it will not also be false.
    You agree, I take it?
    Bartricks

    and that is called the law of non-contradiction. And it is necessary to your entire argument.

    So you have refuted your own argument.
  • Bartricks
    6k
    Question begging. If an argument has that form then it's conclusion will be true if the premises are. That isn't a necessary truth, it is just true. That's what I think and I will reach the same conclusions you do except that I will save myself some breath because I won't say 'necessarily' whereas you will. So I will live a tiny bit longer.
  • Bartricks
    6k
    er, no I haven't. I didn't say it was necessarily true, did I?
    You think contradictions are necessarily false; I think they are just false. So we will both reject the same propositions, it's just that you will add this mysterious word 'necessarily' to your claims of falsehood whereas I won't. What are you adding?
  • Bartricks
    6k
    let me assure you that I care about maintaining validity.
  • Arne
    815
    didn't say it was necessarily true, did I?Bartricks

    You misunderstand.

    I am simply pointing out that logic itself is premised upon what is known as the "law of non-contradiction", i.e., the law of non-contradiction is necessary to logical argument.

    If you will live longer by rejecting the necessity of the law of non-contradiction to logical argument, then go for it.

    I wish you nothing but the best.
  • Bartricks
    6k
    I think you misunderstand. You are just begging the question.
    Look, you are saying that if x presupposes the truth of y, then if x is the case y must be the case, yes?
    What I am saying is that the word 'must' does no work. If x presupposes y, this means that if x is the case then y is too.
    So all you are doing is just inserting necessity claims needlessly.
    I won't just save breath by dispensing with necessity, I'll also be more open minded. I mean, how would you recognize a true contradiction were one to show up given you've closed your mind to their possibility?
  • 180 Proof
    14.1k
    :up:

    :clap:

    Necessity, I think, is a fiction.Bartricks
    ... formal (i.e. logic, mathematics), not fictional.

    There is no necessity in the world.
    Agreed; 'necessary facts' are impossible.
  • Bartricks
    6k
    Contrary to your assertion you do not agree with me. There are no necessary truths; but that is not a necessary truth, it is just true.
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