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All chariot racers are musicians. Some chariot racers are soldiers. Therefore, some musicians are soldiers. Valid or Invalid?

Valid. Your second premise tells you that some chariot racer is a soldier. Let's call him "Alfred". So Alfred is a chariot racer and Alfred is a soldier. So Alfred is a chariot racer. This last fact, combined with the first premise, tells us that Alfred is a musician. But Alfred is also a soldier. So Alfred is both a musician and a soldier. Hence, someone is both a musician and a soldier. Which is your conclusion.

Hi there, I have a very basic question about Frege's object/concept distinction. Please don't make fun of me as I'm new to early analytic philosophy. This question has been bugging me for a while, so I'd appreciate a thorough answer. In sentences like "the cat is grey" or "the cat is in the park," do the words 'the cat' designate an object? If you were to formalize these sentences, I would think it would go as something like: there is some x such that x is a cat and x is grey/in a park. There wouldn't be a uniqueness clause, I would think. If the words that designate an object have to pick out something unique, does that mean the words 'the cat' cannot designate an object (since they are not specified enough)? If they don't designate an object, then what is their logical status? Thanks.

Frege did think that definite descriptions, such as "the President of the United States" or "the cat," are (what he called) proper names, or what are more usually now called singular terms. And he thought that singular terms do denote objects. So I think he did believe that "the cat" refers to an object. The logical structure of the sentence "the cat is in the park" would be something like: Pc. The formalization you offer, "there is some x such that x is a cat and x is in the park," would schematize rather the sentence: some cat is in the park. Perhaps Frege would suggest that "the cat," used properly, is really elliptical for something like "the cat my mother owns." If the definite description really doesn't designate anything, then (in Frege's terminology), it might have a sense but lack a reference. Any sentence containing it might express a thought but would lack a truth value. (The latter claim needs to be qualified to deal with non-extensional contexts.) Hope this helps a bit!

I would like to know if this can be proven I am attempting to prove G with these premises: 1. (-K and -N) > [(-P> K) and (-R> G)] 2. K> N 3. -N and B 4. -P v -R I am not sure if the premises are enough to allow the solver to prove the solution or if there should be additional premises. A response would be appreciated!

Since "-N" is true (3), then from (2), you can infer that "-K" is true. So you know that "-K and -N" is true. Hence from premise (1) you can infer that "(-P > K) and (-R > G)" is true. Hence "-P > K" is true. Since you already showed that "-K" is true, it follows that "P" is true. But if "P" is true then it will follow from premise (4) that "-R" is true. Since you've already shown that "-R > G" is true, you can conclude that "G" is true. If you know what natural deductions are, you might find an online natural deduction proof checker and reconstruct the derivation in that.

Can you define logical validity? I'm engaged in a debate on the subject, with a friend, whom will not easily accept anyones word on the matter, so i would ask that you perhaps post your credentials? thank you for you time and effort!

If you mean "valid argument," that's typically defined as an argument such that there is no interpretation of its premises and conclusions under which all the former are true and the latter is false.

Why does inconsistency entail validity?

Let me spell out the claim I think you have in mind. Any argument whose premises form an inconsistent set of sentences is a valid argument. To understand why this is so, let's be clear about what "inconsistent set of sentences" means and what "valid argument" means in this context. To say that a set of sentences is inconsistent is to say (roughly) that it is not possible that all the sentences in that set are true: they could all be false, some could be true and some false, but there is no way that all could be true. To say that an argument is valid is to say that it's not possible for all its premises to be true and its conclusion at the same time to be false; sometimes people express this by saying that the truth of the premises forces the truth of the conclusion. But now think about it: If you have an argument whose premises are inconsistent, then it's certainly not possible that all its premises be true and its conclusion false - since it's already not possible for all its...

Struggling with Wittgenstein. "The World is all that is the case". Does this mean both positive facts ("Paris is the capitol of France") AND negative facts ("Lyon is not the capitol of France") I can say "It IS the case that Lyon is not the capitol of France". Or does Wittgenstein mean only the pos. facts, i.e what has been actualized? Thanks.

I am not confident about all that Wittgenstein is trying to get at, but one thing he's reaching for might be made clearer by recalling the contrast he sets up: the world is not a collection of things, but of facts. Perhaps the root idea is that if we had to describe the world, we could not do so by simply listing all the objects that there are. Rather, we'd find ourselves saying that this is the case, and that is the case, and so on. We'd find ourselves making a series of that-claims, rather than merely naming objects. That is, we'd list all the facts that obtain.

On 2/2, I asked: What I remember from my philosophy courses is the spirited debate, lively dialogue. For me this site is too question-and-answer, like the Stanford Online Encyclopedia that is often pointed to in the responses. Is there a place on the web where I can find a more dialogue-based form of philosophy? In reply, I received 2 replies bemoaning the quality of thinking found in philosophy chat rooms. I don't believe my question implied that I wanted to chat with morons in a "philosophy chat room", but let me clarify: I graduated with a BA in philosophy from what was then ranked as the #1 liberal arts college in the US, so I'd say I can tell the difference between people who can't reason their way out of paper bags, and philosophers. But the responders seem to imply that, at their level of philosophical accomplishment, there isn't much more to be said after one respondent has answered. In my view, this implies that the quality of the questions is poor, not provoking spirited dialogue from the...

I don't know the answer to your question. There are many philosophy blogs (run by professional philosophers or by graduate students in philosophy) that allow the posting of comments; you might check out some of those to see if they answer to your needs. This site does not yet offer any back-and-forth opportunities (though you might check out the associated Google Groups). Our original idea was to keep the signal-to-noise ratio as high as we possibly could. It would be desirable to add on a feature that would allow comments or more back-and-forth - but in a manner that allowed that feature to be "turned off" by those who prefer not to wade through those further levels of discussion. We're hoping that in a near-future enhancement of the site, we'll be able to implement that.

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