Can we dispense with necessity?
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.
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.
Comments (61)
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?
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?
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?
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.
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?
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?
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
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.
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.
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.
Interesting idea though.
Excellent. :-)
Quoting 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.
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.
I think that if a proposition is true, then it will not also be false.
You agree, I take it?
So you have refuted your own argument.
and that is called the law of non-contradiction. And it is necessary to your entire argument.
So you have refuted your own argument.
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?
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.
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?
:clap:
Quoting Bartricks
... formal (i.e. logic, mathematics), not fictional.
Agreed; 'necessary facts' are impossible.
Well, if you can, demonstrate that "there are no necessary truths" is true.
Strictly speaking, shouldn't that be:
In any possible world with triangles, a triangle will have three sides.
?
Otherwise you might inadvertently have populated all possible worlds with triangles.
Ed: was implicit
But I can anyway:
1. If God exists then there are no necessary truths
2. God exists
3. Therefore there are no necessary truths
Necessarily true refers to logical inference. It can be true that I am walking, and it would be necessarily true that I have legs to walk on. Its about logical sequence when you talk about something being necessarily true. If you are just talking about a specific instance of fact, the it would indeed be incorrect to use “necessarily” true.
So if you adjust your understanding of those terms, you will see how the law of non-contradictions is violated in the concept of omniscience. Hopefully anyway, if Ive explained it clearly.
When you say "if those premises are true, then the conclusion will be as well", you are talking about judgement. If tThe premises are judged as true, then so will be the conclusion. What is that judgement based in if not the necessity of logic? Is it a free will judgement? In this case a person would be free to say that the conclusion will not be true
.Quoting Bartricks
I think the point is that one judges the premises as true, for some reason. That reason need not be stated. So when they say that the conclusion of a logical argument is "necessarily" true, this is a statement as to the reason why it is judged to be true. It is judged as true because of the necessity which the logic produces.
Rather than argue that "necessarily" has no purpose here, because it does serve a purpose, you'd be better off to look at the premises and ask why there is no qualification on the use of "true" in the premise. But wait, there is. It says "if" the premises are true, then the conclusion is necessarily true. So there's no problem at all. It says that if the premises are true, then the conclusion is necessarily true, where "necessarily" refers to the necessity produced by accepting the logic. If you reject the logic, which you could, of your own free will, then you would say that the conclusion is not necessarily true. Therefore "necessarily" clearly serves a purpose. It says that the judgement of truth assigned to the conclusion is dependent on acceptance of the logic.
Apparently not.
So you do not understand, its not clear to you...yet you are still very certain that you aren't confused or need of enlightenment? Am I wasting my time, youre the preacher type not the learning/listening type? You arent even open to the possibility you are wrong here...its best to understand the opposing argument BEFORE concluding its wrong. You admitted yourself its not clear to you.
The laws of logic are necessary to be logical. If you do not want to be logical then ok, but as i said as soon as you do then nobody knows what your talking about, including you. Discarding logic is a commitment to being non-sensical.
... assertion without a valid argument.
You made a claim but I don't see an argument to back up that claim and if you had one, it would like like this:
1.Blah blah blah (premises)
So,
2. There are no necessary truths (conclusion)
2 has to follow necessarily from 1 to make your case i.e. given the premises, the conclusion must be a necessary truth. In other words, either you're making a baseless claim (begging the question) or you're contradicting yourself.
Well said. Much better than the way I put it. (In one of the other threads about the same thing.
I think you are confused about the kind of thing the rules of logic are. The rules of logic are instructions. They don't describe how we think, they 'tell us' how to think. So, we are told to believe that the conclusion is true if the premises are.
Here's an instruction: if they have any butter, but me a pad of butter. That's an instruction and you can follow it. There's no necessity invoked. I am just telling you to do something under certain conditions.
What if I said "if they have any butter, you must buy me some"? Well, that 'must' doesn't indicate the presence of necessity, but rather just serves to emphasize how much I want you to buy me butter.
That's how things are with logic. We are indeed told that if the premises of a valid argument are true, then we 'must' believe the conclusion is true. But this does not indicate that necessity exists.
To return to the point though: "if they have any butter, buy me some" and "if they have any butter, you must buy me some" are both instructions that one can follow. As such one does not need to be told that the conclusion of a valid argument 'must' be true in order to follow logic; that would be akin to thinking that you could only do as I say if I said "if they have any butter you 'must' buy me some" as opposed to just saying "if they have any butter, buy me some".
Logic deals with propositions. "buy me some butter", isn't a proposition. It's an imperative statement. Perhaps you should read up on what a proposition is, but for simplicity, it can be considered as the bearer of a truth/falsity value.
Can you fail to follow a law of logic? Yes, of course one can - this is what happens when one reasons fallaciously.
One 'follows' an argument. You can't follow a proposition. You can follow an instruction.
You have made it clear that you have not understood the subject and that you are unwilling to listen to others. I'll leave you to it.
Then I replied with an argument that you are wrong. Here it is, in case you missed it:
1. If you can fail to follow a law of logic, then the law is prescriptive
2. You can fail to follow a law of logic
3. Therefore, laws of logic are prescriptive.
So, you - you - are the one who does not understand the subject they're confidently pronouncing on.
Here's my argument again:
1. If you can fail to follow a law of logic, then the law is prescriptive
2. You can fail to follow a law of logic
3. Therefore, laws of logic are prescriptive.
Which premise do you deny?
Nor is a conclusion. When we say that the conclusion 'follows' from the premises, then we're appealing to a law, yes?
The conclusion 'follows'......what does that mean? How can a conclusion 'follow'? Does it trail around after the premises? No, what we mean is.....that we are told to believe in the truth of the conclusion if, that is, the premises are true.
That's a command. An imperative. When you make an inference you are attempting to follow such an imperative. Follow. Imperatives can be followed or flouted. The laws of logic are imperatives. Instructions. Prescriptions. That's why we try and 'follow' them. Sigh!
Which premise in the argument I gave you do you deny? Or is the penny dropping that you might just not know what you're talking about and I might, just might, know exactly what I am talking about? "My confusion" indeed!! I am not remotely confused, I assure you.
1. If you can fail to follow a law of logic, then the law is prescriptive
2. You can fail to follow a law of logic
3. Therefore, laws of logic are prescriptive.
Which premise is false? Or is it sound? It's sound, yes?
Prescriptions are relations. The premises are related to the conclusion by the prescription constitutive of a law of logic. We are told - instructed - to believe that if the premises of the above argument are true, then to believe the conclusion is true. The premises are not the instruction and nor is the conclusion or our act of believing it. The law of logic is the instruction. And it relates the premises to the conclusion and to us.
But you're not listening at this point, are you? I'm just soooo confused, yes?
I still think you have failed to see the distinction between premises themselves and their relations.
Can you explain what you mean by "favoring relation"?
"you can fail to follow a law of logic" is also nonsense statement. Can you reword it?
Right, so "necessarily" means that you will judge the conclusion as true if you adhere to the rules, instructions.
Quoting Bartricks
Clearly there is necessity invoked here. You are telling me that if they have butter then I need to get you a pad of butter, you are just not explicit with the "need". It's completely similar to the example of logic. I can of my own free choice, choose not to get you the butter, and this means that I do not see the need, just like you can of your own free choice choose not to follow the logic, and this means that you do not see the need. In the case of the logic we are explicit, using "necessarily".
Quoting Bartricks
That's correct, but the issue you've brought up is whether or not "necessarily" serves a purpose, and it clearly does. It indicates that the conclusion is judged to be true only if you agree with the logical principles employed. So the "necessity" is within you, as the need to produce a conclusion. The judgement that the conclusion is true is contingent on you apprehending that need, just like me getting the butter for you is contingent on me apprehending the need. In the case of the logic we are explicit to describe what produces the need, the logical process. In the case of the butter you are not explicit as to why I need to get butter for you.
Quoting Bartricks
In the case of the logic, we are told that if we follow the logic we must accept the conclusion. In the case of the butter, there are many ways you could ask, "can you buy me some?", "please buy me some", etc.. Or, as you say "buy me some". They are all ways of asking. If I am agreeable, I will apprehend the need, and buy you some. You might also say "you must buy me some", and the same principle holds, you are still asking me to buy you some, and if I see the need, and am agreeable, I will.
So, in the case of the logic we are given the reason we we ought to accept the conclusion. "Necessarily' represents the reason, which is that the logic backs up the conclusion. In the case of the butter you are not giving me the reason why I "must" buy you some. So the two are not comparable. With the logic "necessarily" gives reference to the logic, demonstrating the need. Unless you provide why I "must" buy you the butter, support the "must", as "necessarily" is supported by the logic, eg. you will die without it, then the "must" doesn't do the same thing as the "necessarily" does.
If I say "it's necessary for you to buy me some butter" what do I mean? Do I mean that it is a necessary truth that you will buy me some butter? No, clearly not. I mean that it is urgent, important, imperative, that you do so. That's typically what words such as 'must' 'always' 'never' and so on mean when we use them.
So, the language of necessity is used in everyday life not to describe the world, but simply to emphasize things - that is, it functions 'expressively'.
But philosophers - most, anyway - think that there is this weird thing 'metaphysical necessity'. It's a strange glue that binds things immovably. So, a 'necessary truth', on their usage, is not a truth it is extremely important that you believe (which is what it'd be if the word 'necessary' was functioning expressively), but a truth that cannot be anything other than true - so a proposition that has truth bonded to it so strongly that it can never come away.
Now, 'that' kind of necessity - metaphysical necessity - is the kind that I am suggesting we can dispense with. It is really just a case, I think, of us taking language that normally functions expressively, literally. As such we can dispense with it.
I dispense with it - I don't believe in metaphysical necessity - yet I seem able to reason just as well as everyone else. It's just when I draw a conclusion, I think the conclusion 'is' true, whereas others will think that it is 'necessarily' true. But there's no real difference. It's not like there are two grades of truth. There are just true propositions and false propositions and a story to tell about how they got to be that way.
Incidentally, if one thinks necessity does exist, then what I want to know is what the truth-maker for 'necessarily' true is.
Yes, I'd say that "necessary" here means that there is good reason for it.
Quoting Bartricks
Oh, I see the problem, you think there is some sort of "metaphysical necessity" referred to, which is a "strange glue" , and that's why you don't like the usage. I suggest you just release that idea of a metaphysical necessity, and just look at "necessity" here in the normal way, as meaning "good reason", and your problem will be solved.
Quoting Bartricks
OK, I agree there's no need to assume this "metaphysical necessity". But do you agree that when the conclusion follows logically from the premises, then it is "necessary" in the normal sense, meaning that there is good reason for it?
Quoting Bartricks
I tend to think that there are different grades of truth, depending on the reasons the person has for believing what is believed. True or false is a judgement we make, and the judgement can be made for a variety of different reasons, some better than others. So, suppose that the truth of the conclusion is dependent on both the truth of the premises, and the strength of the logic employed. If this is the case, then the truth of the premise is a higher grade of truth than the truth of the conclusion, because it is more likely that the conclusion would be false.