Can i prove logic?

Question

It seems that in order to prove logic, one would need to assume logic, so the proof would assume its own truth, thus being circular.

But is there not another way to prove logic? Take for example "if A is bigger than B, and if B is bigger than C, then A is necessarily bigger than C". This is necessarily true.

The above has supposedly to be taken on faith but consider the following experiment.

Let's say i put three rocks of different sizes next to each other. I name them A, B and C. Now, from this observation it will be evident that if A is bigger than B and if B is bigger than C then there is no alternative but to keep A as the biggest rock. It is evident from the senses.

According to me, logic can be demonstrated this way, but not according to the philosophers. Can anybody show me where my reasoning fails?

br/GH

Answer 1

Your reasoning fails simply because the significance of the original premise is that it is supposed to apply everywhere, to any possible A, B, or C, or at least to some broad and specified category.

Assuming no mistakes (from a failure to take account of perspective etc.), your experiment has shown only that the premise holds for these particular three rocks. You could repeat the experiment, and then the accumulation of examples would make for an "induction," but there's plenty of room for argument about what or when anything universal is proven that way.

Answer 2

I took one 100 level philosophy class: Knowledge and Reality, in college.

Well it might be that our senses might deceive us. I think the philosophers are saying that our senses can be deceiving because we are looking at effects, which can be mutable, i.e. changeable.

If I remember correctly there was an example of a piece of wax, that at one time was a certain form, but as it melted it became something different. And I think the only that didn't change was the essence of the wax.

But I suppose the example you gave with the three rocks, could be that if it's an irregular shape then it might be harder to tell if one is bigger than one, and so just because we look at it with our eyes, doesn't mean that it is bigger. Then there is density of the rocks you probably have to consider. But for this situation I think you are trying to find volume.

A better way, I would assume is to weigh them or see how much water it displaces when it is dunked in a bowl of water. This would give us a better way to measure it, using numbers, which are immutable, then to rely on physical senses which may not be able to tell how big something really is. If Rock A displaces 50 mm^3 of water, Rock B 45 mm^3, and Rock C 40 mm^3. Then I think you can accurately conclude that Rock A is the biggest, then comes Rock B, and then the smallest would be Rock C.

Answer 3

Logic is the notion that there is consistency between various causes & specific effects. Like the notion that if you let go of rocks in the air - they consistently fall. Proof is basically when you describe a cause-effect relationship and everyone else that tries it consistently gets the same results. Now as Hume eloquently argued, the fact something happens a certain way a thousand times does not guarantee it will happen that way the next time. - but lets get real here, that is the way to bet. So sure, if you set your standard high enough there's no such thing as proof. None the less men will still buy books on how to pick up women, and women will still go on supermodel diets because we BELIEVE. So get a little fricken FAITH in your life or risk spending the rest of your pathetic little life mumbling at the wall. Socrates said it best: "We know nothing" to which the Phoenix replies: "Yes, but all guesses are NOT created equal" I assume the universe is Logical, because to assume otherwise is pointless. (Kudos though on realizing Logic is an assumption - not something we can logically arrive at)

Answer 4

logic is a science, it proves things in relation to an existing basis.

like 1+1 = 2. why is this so? it's "logically right" because of an existing numerical system on which this is based on.

logic only exists when there's a basis.

can you prove logic? logic is the art of proving something.

so i dont think you'd actually want to prove youre proving something.

but if you really did, then youd have to prove that there's a basis. philosophically, bases are not reliable. since they are assumed truths, nothing can be certain. if nothing is certain, then how can you prove it is so?

also, anything proven to be right by the senses is taken to be unreliable as well. like the classic case of the blind men all touching a different part of the elephant, and each assuming an elephant to be the part he is touching alone and nothing more.

logic, can thus be proven, depending on what you are proving, and how you are proving it.

but alas, there will always be cases where you cant prove it, and thus it is why it is not logical anymore and there is no need to prove it so.

Answer 5

You can't. This is where I really like the Critique of Pure Reason. My professor's simple explanation of Kant was that he acknowledged the failures of reason and the problem posed by Hume where basically we cannot know anything. (Hume argued that we do not 'see' cause and effect. We just get used to it as part of custom.)

Descartes had the same problem which he solved only with a bit of intellectual dishonesty on his part. The only thing Descartes can really know from his reasoning is that "he exists" but he cannot validly prove that other things exist.

But when Kant tackled the problem, he no longer asked "whether or not we actually know". He makes the initial assumption that we know, and only tackled the problem how do we know?

Reason is the tool that is already in our head that allows us to know. It requires no proof. It is already how our head works.

Now as for your "reasoning", how exactly can you use "reasoning" to prove "reason"?

Answer 6

Logic is point of view specific. That is each of us see things from our own unique perspective.

This makes perception a rather uneven tool for basing our observations on.

What looks one way to us from our unique but limited perspective, may look completely different to someone with a different perspective.

love and blessings Don

Answer 7

i think you could perhaps prove mathematical logic, using resolution, that way,
resolution is deriving a conclusion based solely on what one already knows
there are many types and models of logic, what works for one wouldnt for another

Answer 8

You don't prove logic. Logic does the proving.

Answer 9

logic can't be applied everywhere.
Man has two eyes. Owl has two eyes. man is owl.
A is bigger than B, A is bigger than C so B and C, both are smaller than A hence they are equal, it may be so or it may not be so.