# Tag Info

Accepted

### If I said I had \$100 when asked, but I actually had \$200, would I be lying by omission?

I would say it depends on the situation. Specifically, it depends on whether the person asking you the question wants to know whether you have at least \$100, or exactly \$100. The question could ...
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### If I said I had \$100 when asked, but I actually had \$200, would I be lying by omission?

tl;dr- It's a lie if the speaker intends to deceive the listener(s). More specifically, it's a lie-by-omission if the speaker intends to deceive the listener(s) by neglecting to mention something ...
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### Why is it that the statement "All goblins are yellow" does not contradict the statement "All goblins are pink?"

Edit in response to your comment: Okay, long answer: What is the meaning of "the"? (A previous version of the question had the statement "The goblins are pink"; this is an ...
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### Do computers use logic?

Allow me to be precise about this. Logic (in the formal sense) is a system of manipulating symbols according to rules. Computers can manipulate symbols according to rules — that is more or less ...
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### If you used intuitionistic logic in real life, would you not sound absurd?

As Conifold comments, a real-life intuitionist would not shy away from assuming LEM ... when appropriate. Intuitionism merely permits the failure of LEM, it doesn't assert that it always occurs. For ...
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### Why isn't the Liar's Paradox just accepted to be complete nonsense?

You ask: Why isn't the Liar's Paradox just accepted to be complete nonsense? You want an answer in "plain English." The easy explanation is that "complete nonsense" intuitively ...
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### Why did the mid-19th century and earlier thinkers fixate on one-place predicates?

Because there was a calculus for one-place predicates, Aristotle's syllogistic, roughly equivalent to monadic predicate calculus. Aristotle does discuss "relatives" in Categories, which ...
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### Why is it that the statement "All goblins are yellow" does not contradict the statement "All goblins are pink?"

There are two ways in which these statements can be non-contradictory: Option A: Non-mutually exclusive It is possible for a goblin to be both pink and yellow, therefore it is possible for a goblin to ...
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### Why are there two fundamental laws of logic?

They're not equivalent, but they do seem very close together in most contexts when you assume a bivalent (two truth valued) logic. But they pull apart when it comes to several controversial ...

### Why did we define vacuous statements as true rather than false?

We do NOT define vacuous statements as true. A vacuously true statement is vacuously true. A "vacuously false" statement is vacuously false; although nobody ever gives this type of statement any ...
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### Has Münchhausen's trilemma been solved?

The Muenchhausen Trilemma is a philosophical insight, not a philosophical problem. Hence there is no need for a solution, but the call for application. The trilemma was formulated by Hans Albert. It ...
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### Can it be proven from pure logic that at least one thing exists?

To expand a little on causative's comment. In standard logic, it is a convention to assume that the universe of quantification is non-empty, which is to say that at least one thing exists. It we don't ...
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### Can it be proven from pure logic that at least one thing exists?

Just the fact that you are pondering this question confirms that you exist – according to Descartes, see Cogito ergo sum. Also Anselm considered his ontological argument to be a proof of the existence ...
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### What is the axiom of reducibility? And what philosophical controversies did it incite?

To put it in simple words we have to describe in a couple of words the project of Principia Mathematica, which Russell inherited from Frege: reconstructing mathematics from logic alone. For a broader ...
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### Do premises need to be valid conclusions?

Validity in logic is a somewhat tricky notion to understand as it is different – though only subtly – from related, pre-theoretic notions. For instance, not every valid argument is ‘convincing’ or ‘...
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### How come intuitive thinking is related to constructing a proof?

Intuitionism is a philosophy of mathematics that was introduced by the Dutch mathematician Luitzen Egbertus Jan Brouwer (1881–1966): he developed a very personal philosophy of mathematics that founds ...
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### What is the difference between 'accidental' and 'contingent'?

Colloquial meanings of the two words are pretty close, accidental is "occurring unexpectedly or by chance", contingent is "subject to chance; occurring or existing only if (certain circumstances) are ...
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### Is finding truth possible?

You've stumbled upon an old problem in philosophy, The Paradox of Inquiry, first formulated in Plato's Meno. The problem can be reformulated as follows: Either you know the answer to a question, or ...
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### Is there an English language example where modus tollens is valid but contraposition is not valid?

Here's the example from David Lewis's Counterfactuals (1973): If Boris had gone to the party, Olga would have gone. Now suppose that Boris wants to go, but not if Olga goes, because he wants to ...
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### If I said I had \$100 when asked, but I actually had \$200, would I be lying by omission?

Your question is about lying by omission, and this requires that you define lying. The definition I use is a communication with the intent to deceive. Thus, whether or not you are lying is a function ...
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### If you used intuitionistic logic in real life, would you not sound absurd?

Propositions in intuitionistic logic are probably best understood as statements about provability. P ʌ Q means that you can prove P and prove Q, ¬P means that from P you can derive a contradiction, ∃x....
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### Is there a system of logic which denies DNI?

Yes there is. As you say, intuitionistic logic has DNI but not DNE. There are also dual-intuitionistic logics whose connectives operate in a fashion that is dual to those of intuitionistic logic. Dual-...
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### What are the differences between philosophies presupposing one Logic versus many logics?

It is more complicated than a merely instrumental/metaphysical division. The "logics as mere instruments" were not meaningful until well into the 20th century, after the general ...
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### Do logically incoherent statements still have meaning?

My reading of Carnap's "The Elimination of Metaphysics Through Logical Analysis of Language" suggests to me that it is possible to form sentences in a language that are grammatically correct but ...
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### Is it logically permissible to neither believe nor disbelieve a proposition X? Or does this violate the law of excluded middle?

You seem to confuse belief (which is subjective) and the actual truth value of a proposition. The LEM only applies to the latter, not to the former. If you wish to stay inside a mathematical framework,...
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### Does the Fallacy Fallacy make logic useless?

Short answer: definitely no, that does not make logic useless. When someone makes an invalid argument, they're committing some sort of a formal fallacy. That is only to say that the conclusion does ...
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### Logic and Computation: a philosophical viewpoint on Curry-Howard isomorphism

I think you are right to be impressed with the Curry-Howard correspondence. It is a detailed and extensive rule-by-rule and feature-by-feature isomorphism. This strongly suggests that proof and ...
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