Why is that if P entails not-Q and Q (a contradiction) do we conclude not-P? I understand that this a reductio ad absurdum and that because of the law of bivalence P either has to be true or false so if it entails a contradiction it is proved not true therefore false. But that last step is what I can't seem to justify...why does it become Not-P if it entails a contradiction? If I had to guess it's because contradictions don't exist in real life so if P were true and it entailed something that could never exist then it must be the case that P is not true (and this is true because of modus tollens: not-Q entails not-P). But we are dealing with symbols in the case of formal logic so how does this apply? Is formal logic an analogy of real life? I hope the question is clear after this rant!

I'll confess that I'm not sure I have your question right. You've given a pretty good explanation of why P can't be true if it entails a contradiction. I'd rephrase the way you put it, however. Instead of saying "contradictions don't exist in real life," I'd say "contradictory statements are never true." But as you in effect note, if a statement entails a contradiction, then the statemetn could only be true if a contradiction were true. That can't happen, so the statement must be false. So far so good. Your worry has to do with that fact that we are dealing with symbols and formal logic rather than "real life. " But the point of the the symbols is just to let us talk in general. The schema is (roughly) that whenever P entails a contradiction, P is false. That's shorthand for saying that whenever a statement entails a contradiction, the statement can't be true. In other words, Pick any "real life" statement you like that entails a contradiction. Then the statement is false. Notice that...

I have a question concerning the gender of words that exist in many languages, except in English. What does the presence of grammatical gender in a language say about the mentality of its speakers? A different question is whether the features of a language reflect the characteristics of the societies where it's spoken in a largely unconscious and involuntary way. (Modern) Persian, spoken in Iran and Afghanistan, doesn't have the feature of grammatical gender (anymore), just as English. Many say that the languages that do have grammatical genders are sexist, and that they help to perpetuate the conviction that sex is a tremendously important matter in all areas. For Marilyn Frye, this is a key factor in perpetuating male dominance: male dominance requires the belief that men and women are importantly different from each other, so anything that contributes to the impression that sex differences are important is therefore a contributor to male dominance. Societies whose languages do not have...

You've several questions, though they're closely related. Let me start with the first one: "What does the presence of grammatical gender in a language say about the mentality of its speakers?" My answer is: "Darned if I know!" But I rather suspect that most of my co-panelists are in the same position. Whether the presence of grammatical gender in a language has an effect on the outlook of people who speak it is something we could only figure out by bringing to bear the reseources of disciplines like sociology, psychology, sociolinguistics and who knows what else. It would also call for refining the question itself to the point where we knew what counts as an answer. As you yourself observe, it's not exactly obvious that societies whose languages don't mark gender are less sexist than their grammatically gendered counterparts. If there is an effect here, one suspects that it's a subtle one, and not easy to tease out. It may well be that if the people in a society believe that men and women are ...

Is there any good argument to support the claim that homosexuality is a perfectly valid lifestyle?

I'd suggest reflecting on a different question: is there any good argument to support the claim that it isn't? I ask this because for my own part, I can't think of one. Further, I don't think this is just a failure of imagination on my part. When I think about the same-sex couples I know, the fact that both partners are men or both are women fades into the background pretty quickly. I've known dysfunctional same-sex couples, and dysfunctional opposite-sex couples. I've seen loving, sustaining, healthy same-sex relationships, and loving, sustaining, healthy opposite-sex relationships. Some homosexual people are abusive; so are some heterosexual people. Some heterosexual people are just the sort of people you'd be glad to see your own child in a relationship with. And so are some homosexual people. Now it's true: homosexual sex isn't procreative. Neither is sex with birth control. Nor is celibacy. It's also true: if everyone were homosexual, the survival of the species would be a lot more...

I'd like to challenge the validity of the "Ad Hominem" fallacy - it seems to rest on a certain metaphysics. At the very least, this metaphysics should be argued, not assumed, in my view. The separation of a person from his/her ideas strikes me as certainly not obvious. Isn't this the reason why we urge people not to discuss religion and politics with each other? Because their views, expressive of their very identities, can offend us?

On the one hand, there is still a real fallacy of the sort we label ad hominem . The fallacy consists in claiming that a person's conclusion should be rejected because they have a bad character or have an ulterior motive. This is a fallacy because I don't have good grounds for saying that the conclusion is false. A bad person can occasionally offer a good argument, and a conclusion can be plausible even if it's argued for by someone of suspect character. Further, in the wild, so to speak, ad hominem arguments are often the last (or first) resort of intellectual scoundrels who want to divert attention from the poverty of their own case. That said, there's a familiar sort of move that all of us make legitimately. Suppose, for example, that I am not an expert on some controversial topic, but I do realize that coming to sound conclusions is hard and that I'm not in a position to sort good arguments from bad. Suppose I come across an argument by someone who has something at stake, and who has a...

I used to love my work and see it as a path to a virtuous happiness and sense of self-fulfillment. But working for someone else had changed all that; amidst the petty slights, status contests, and probably just far too many hours in the office working for people who don't treat me well (with no choice about when or what I work on), my work has lost all its meaning. I feel like I built up a false belief system about achievement, and it worked for 27 years, but it's now come crashing down. I know I listed some probable causes, but I'm sure it could be explained more philosphically and eloquently. I need to better understand in abstract terms - what causes meaning to erode? And what have philosophers suggested as cures for such existential crises?

Sorry to hear of your distress. And I'm also sorry that I don't have a lot of insight to offer, except but of negative advice. When you wonder what causes meaning to erode, there are two rather different sorts of things you might be asking. One is what sorts of reasons and arguments might persuade us that things don't have the cosmic significance we thought they did. Some philosophers have had things to say about that, and you might find Thomas Nagel's classic article "The Absurd" (Journal of Philosophy, 1971 pp. 716-727) interesting as an example. But Nagel cautions that even if his diagnosis of the absurdity of things is correct, it doesn't give us a reason to worry about it. Put in a different way, perhaps, a philosophical account of how things mean less than they seem needn't get in the way of a rich and enjoyable existence. And that brings me to what I suspect is the real point. Many of us have gone through periods when things seem meaningless to us not just in some abstract philosophical...

How can you think that your opinion is worth anything when all your opinion is is a thought process that came to you as a result of everything that happened in your extremely unique life? If you look at all the other arguments that go against your own beliefs, the people saying them believe them as truth. So do you ever think that you're just as equal as they are, or do you actually think that you're more "on the right track" than they are? Finally, if I always understand and justify why people think the way they do regardless of the subject, then how can I think that my own opinion matters, if, again, my own opinion is only a result of how I see things in my mind, because of everything around me that led to me being who I am today.

There are a couple of ways we might think about the questions you're raising. One is by trying to look for an Archimedean Point, so to speak, that provides some sort of absolute or incontrovertible answer. The other way is to look at how we actually think about these sort of things -- look from the inside. Since I have no Archimedean point available to me, I'll offer the latter sort of response. What we think does depend on what we've experienced, but even though my life is different from yours, we have lots of common ground to appeal to. Obvious sort of case: if you and I were both to look out my office window, then even though your experience is not just like mine, we'd agree that there's a building directly across from us. We'd also agree that there's a large grassy area behind it, and that there are people wandering around in the vicinity. Other cases of ho-hum agreement among people are more complicated, but we could multiply examples indefinitely. We can also agree that some people are...

Is it immoral for a health insurance company to refuse to cover a person with a pre-existing condition?

Timely! I'm inclined to tinker a bit with the question. First, I think it's a scandal that in the USA, people with pre-existing conditions often can't get health insurance. Other developed countries have figured this out; it's about time the US caught up. However, given the way the system works at present, we might get a fix on your issue by asking this. Suppose I'm in a position to set up a not-so-large company that provides health insurance, but I'm not willing to take on the risk of insuring people with certain pre-existing conditions; I'm worried that if I do, the company will be bankrupted and then won't be able to insure anyone. (I'm not saying this is actually the case for most big health insurance companies, but bear with me.) So long as I'm upfront and honest about what I'm offering, it's not clear that I do wrong by offering my more limited product. It's in the nature of private insurance schemes that the companies are in the business of risk management. Companies that don't make...

Recently I read an article in a newspaper about belief in God. The author was quite disparaging about atheists, maintaining that they have some essential flaw in their make-up. The author could not understand how anyone would chose to not believe in God. I am a Catholic and was always taught that "you must believe in God" and that "disbelievers would be punished". I was frightened by this and by the story of Doubting Thomas who didn't believe that Christ had risen from the dead as I knew that I wouldn't have believed that purported fact either. My question is can you choose to believe? I would think not.

An interesting question. On the one hand, we can't simply choose to believe or not believe things. I couldn't simply decide to believe that Paraguay is in Africa, for example. But there are things we can do that make it more or less likely that we'll end up with certain beliefs. Pascal famously suggested that one might be able to become a religious believer by going to mass, hanging out with believers, and so on. To some extent and for some people, this strategy probably works. We can also go out of our way to avoid hearing about evidence that counts against what we want to believe, and to hear only things that count in favor of the belief. To whatever extent strategies like this work, they amount to indirect ways of "choosing" our beliefs, though I'd be reluctant to drop the shudder quotes. On the specific question, however, many people become atheists because belief in God becomes hard to sustain. They don't decide to become atheists; they simply find that at some point, their theism gives...

Say there is a music band whose members engage in frequent illegal/immoral acts, e.g. drunken driving, drug use, prostitution, rape, assault, etc. I want to buy their latest album, but I know that the money they receive from me will end up fueling their criminal behavior. Knowing this, is it wrong for me to buy the album?

You've given some good reasons for not buying the album. And since it's hard to make the case that you need this particular album, the reasons seem pretty strong - strong enough to convince me, at least. That said, there's a larger and harder issue here, and I'm guessing you may have it in the back of your mind. Many of us spend money at businesses whose practices we really wouldn't approve of if we let ourselves think about it. Perhaps they buy goods from sweat shops. Perhaps they have despicable labor practices. Without pretending that this does justice to the matter, a couple of issues strike me. One has to do with thresholds and balances. At what point are the practices of a business "bad enough" or insufficiently offset by the value of what they provide (including employment) that I should stop patronizing them? And how strong are my obligations to inform myself? I may know that business X has some very nasty practices. I might decide to patronize business Y instead, but the only...

Peter Smith wrote recently (Question 2823) that "facts aren't the sort of thing that are rational or irrational". But that isn't true, is it? The first definition of the word "rational" on dictionary.com is "agreeable to reason". Certain facts offend reason - and the questioner's example (while not the best, in my view) of death seems to be a fact that is not agreeable to reason. That is to say, if reason ruled the world or, put another way, if God created everything in accordance with reason, we would not die. There is no rational explanation or reason for our death. Certainly there is a sense in which I understand Peter Smith's statement that facts aren't rational or irrational, but there seem to be plenty of definitions of "rational" for which it makes perfect sense to say that facts are rational or irrational. What's more - and I don't mean to be contentious - Peter seems to focus on this aspect of the question to the detriment of the spirit of the question. The questioner seems perturbed by...

Not to be flippant (well, yes: to be flippant) but I'm tempted to point to Peter Smith's earlier reply and say "What he said!" Let's grant that in one sense of the word "irrational," some of life's surd facts are irrational -- aren't how things would be if a rational Maker had her way. Prof. Smith acknowledges that some facts are difficult to cope with emotionally. And he might add (I'll add it for him) that being rational doesn't mean ignoring your emotions or trying to stuff them into a sack. But how, exactly, would it help to leave reason aside in dealing with tragic, intractable facts? Prof. Smith's closing comment seems to me to be a sober, thoughtful way of summing it up: "For irrationally formed beliefs are not likely to lead to actions whichget any of us what we want -- including a decent life, lived well inthe knowledge of our all-too-explicable mortality." The language of philosophy is seldom poetic; in that sense it may not mirror the gravity of some of its subject matter. That said, the...

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