In logic, specifically in deductive reasoning, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false. It is not required for a valid argument to have premises that are actually true, but to have premises that, if they were true, would guarantee the truth of the argument's conclusion.
In logic, more precisely in deductive reasoning, an argument is sound if it is both valid in form and its premises are true.
If for example, the grass is wet, it has to have become wet somehow. If we were in a world where this can only happen by rain, the conclusion clearly is that it must have rained. — Heiko
It provides a guarantee of understandability for other beings. I guess you could get an agreement of any realist when showing the fundamental set operations - e.g. "O O is disjoint" and he will agree that no point in one O is also in the other. It is not so much the content but the basic rules of logic themselves that have a certain type of "reality".I am looking for an argument of what logic does for the realist besides act as a useful heuristic. — Ennui Elucidator
Other than that - I do not understand your concept of rTruth completely: E.g. If you feel a poke in the back, is there "really" something that pokes you? I guess the answer is "no": it is a conclusion that everything has cause. I am not sure that all realists would reduce reality to just the given content of consciousness. In another thread I pointed out that (following e.g. Heidegger) reality seems to be purely negative - that it is mainly what _prevents_ you to assume something. In logics this would be a statement not(x) where x is the "state of affairs as assumed". — Heiko
Okay, nice to meet you :)I am, however, interested in non-binary, relevant, paraconistent, etc. logics and how they solve real world problems that classical logic (however slightly modified) cannot (or perhaps they solve such problems more efficiently). — Ennui Elucidator
I’m not sure what you mean by “seems to evaluate” in this case. My hope was that by using a mathematical truth as the antecedent, that we could highlight that any true premises plus valid form makes “P” true of logical necessity. Logic is, perhaps, about establishing (discovering?) the rules by which the truth value of one proposition relates to the truth value of another. Classical logic, where any proposition can stand in for any other proposition with the same truth value, leads to many intuitively unsatisfactory “proofs”. — Ennui Elucidator
I am looking for an argument as to why anyone should feel compelled to accept classical logical (or minor variations) as somehow more useful as a heuristic than any other logic. — Ennui Elucidator
Indeed, why not make Eristische Dialektik our Bible?In particular, I am looking for an argument as to why anyone should feel compelled to accept classical logical (or minor variations) as somehow more useful as a heuristic than any other logic. — Ennui Elucidator
My inclination is to say simply that we can choose whatever logic suits our purpose. DO you thin this somehow incompatible with realism? — Banno
Well I don’t understand the Bible in Latin or German, why should another German book that I don’t understand fail to qualify as a bible? The title sounds grand though.Indeed, why not makeEristische Dialektik our Bible? — baker
Persuade the Audience, Not The Opponent
This is chiefly practicable in a dispute between scholars in the presence of the unlearned. If you have no argument ad rem, and none either ad hominem, you can make one ad auditores; that is to say, you can start some invalid objection, which, however, only an expert sees to be invalid. Now your opponent is an expert, but those who form your audience are not, and accordingly in their eyes he is defeated; particularly if the objection which you make places him in any ridiculous light. People are ready to laugh, and you have the laughers on your side. To show that your objection is an idle one, would require a long explanation on the part of your opponent, and a reference to the principles of the branch of knowledge in question, or to the elements of the matter which you are discussing; and people are not disposed to listen to it. For example, your opponent states that in the original formation of a mountain-range the granite and other elements in its composition were, by reason of their high temperature, in a fluid or molten state; that the temperature must have amounted to some 480 degrees Fahrenheit; and that when the mass took shape it was covered by the sea. You reply, by an argument ad auditores, that at that temperature - nay, indeed, long before it had been reached, namely, at 212 degrees Fahrenheit - the sea would have been boiled away, and spread through the air in the form of steam. At this the audience laughs. To refute the objection, your opponent would have to show that the boiling-point depends not only on the degree of warmth, but also on the atmospheric pressure; and that as soon as about half the sea-water had gone off in the shape of steam, this pressure would be so greatly increased that the rest of it would fail to boil even at a temperature of 480 degrees. He is debarred from giving this explanation, as it would require a treatise to demonstrate the matter to those who had no acquaintance with physics. — “The Art of Being Right”
There are some alternative mathematical logics which account for the (un-)provability problem by eliminating the tertium-non-datur and the law of the double-negation by saying "x" means that "a proof can be contructed for x" and "not(x)" means "a proof can be constructed for not(x)". Doing this a failure to construct a proof for "not(x)" no longer necessarily implies "x", which makes the logic weaker (and suitable for an open world). — Heiko
I am suggesting quite the opposite - that if truthmakers are states of affairs, then logic should not be faulted for its failure to ensure rTruth. — Ennui Elucidator
Agreed.Although not fully explicated here, the thought is that the way that speak of truth is neither about coherence nor correspondence, but about achieving our ends. — Ennui Elucidator
Unless this belief (or, to the point: asserting this belief) is part of the realist's strategy to achieve his ends.It would be nice, however, if the realist would cease their reproach of logics that don’t meet their aesthetic based upon the faulty belief that logic is about the state of affairs.
Ideally, fending against informal logical fallacies should protect one against being duped (and, if one is very nice, make one refrain from duping others). — baker
Indeed.I want very much to like this, but there are times when informal fallacies are useful - like appeals to authority or ad hominem when it is so much more trouble to show why the person is wrong. If an informal fallacy gets you to the same end with more expedience, I question why they shouldn’t be given the same status as any other heuristic. — Ennui Elucidator
For example, I may advance a proof of some assertion, and my adversary may refute the proof, and thus appear to have refuted the assertion, for which there may, nevertheless, be other proofs. In this case, of course, my adversary and I change places: he comes off best, although, as a matter of fact, he is in the wrong.
If the reader asks how this is, I reply that it is simply the natural baseness of human nature. If human nature were not base, but thoroughly honourable, we should in every debate have no other aim than the discovery of truth; we should not in the least care whether the truth proved to be in favour of the opinion which we had begun by expressing, or of the opinion of our adversary. That we should regard as a matter of no moment, or, at any rate, of very secondary consequence; but, as things are, it is the main concern. Our innate vanity, which is particularly sensitive in reference to our intellectual powers, will not suffer us to allow that our first position was wrong and our adversary's right. The way out of this difficulty would be simply to take the trouble always to form a correct judgment. For this a man would have to think before he spoke. But, with most men, innate vanity is accompanied by loquacity and innate
dishonesty. They speak before they think; and even though they may afterwards perceive that they are wrong, and that what they assert is false, they want it to seem the contrary. The interest in truth, which may be presumed to have been their only motive when they stated the proposition alleged to be true, now gives way to the interests of vanity: and so, for the sake of vanity, what is true must seem false, and what is false must seem true.
I am suggesting quite the opposite — Ennui Elucidator
DO you thin this somehow incompatible with realism? — Banno
Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.