Is length an intrinsic property or is it something which is only relative to other lengths? Is an inch an inch? Or is it simply a relation between other (length) phenomena?

It is indeed an interesting question, and in fact it's more than one question. To begin with, my colleague is correct: in special relativity, length is like velocity in classical mechanics: it's a "frame-dependent" quantity. However, the theory of relativity is also a theory of absolutes; between any two points in space-time there is a quantity called the interval , and it is not frame-dependent. To put it in the jargon of relativity, the space-time of special relativity has a metric -- a generalized "distance function" -- and that metric delivers an unequivocal answer to the question of whether the interval between w and x is equal to the interval between y and z. But now we have a new question: suppose that relativity says that the interval between w and x is, in fact, the same as the interval between y and z. What kind of fact is that? Suppose that the two intervals have no overlap. Doing business as usual, so to speak, we come up with the answer that the intervals are equal, but we ...

Am I a hypocrite if I support gun control while owning guns myself?

Being in favor of "gun control" covers a lot of territory — from modest reform of gun laws to outright prohibition.But a hypocrite is someone who exempts himself from his own stated principles. If the sort of gun control you favor is something you'd be willing to apply in your own case, there's no hypocrisy.

Do polygamy bans violate the natural rights of bisexuals? In wake of the current Supreme Court debate in the US that gay marriage bans violate due process and equal protection guarantees, I want to ask a philosopher whether these two legal concepts, due process and equal protection (which go by different names in different countries), are derived from natural philosophical rights. If so and assuming that they are similar in meaning, does that mean that at least philosophically speaking, polygamy irrespective of particular examples is NOT inherently immoral? The main philosophical argument for gay marriage from what I've heard is that since sexual orientation is a fundamental and largely unchangeable part of a person's nature, it is immoral to deny gays a right that straight people have. But what about bisexuals? Isn't a bisexual woman or man who is in a serious relationship with both a man and a woman at the same time just as deserving? I don't think it matters whether or not the other two members of the...

I'm not sure I have your question clearly in my sights, but I think it's something like this: As it stands the only kind of marriage many countries recognize is between one man and one woman. Advocates of same-sex marriage argue that for a variety of reasons, not least the fact that sexual orientation isn't simply a choice, we ought to recognize same-sex marriages as well. Otherwise, there's a serious issue of fairness and justice. Your suggestion is that this leaves a particular injustice unaddressed: bisexual people who are in relationships with men and women at the same time. If same-sex marriage is the cure for discrimination against homosexual relationships, then, so the thought goes, polygamous marriage is the cure for the parallel injustice against bisexuals. Here's why I'm not persuaded. Leave hetero- vs. homo- vs. bisexuality aside. Some people are in love with more than one person. Call people capable of such attachments polyamorous. In some cases, all concerned parties would be more...

Are dreams an instance of the imagination, hallucination or something else?

There is an interesting discussion of this question in a recent paper by Jonathan Ichikawa. You can find a downloadable pre-publication version at http://philpapers.org/rec/ICHDAI Briefly, Ichikawa sees dreams as a form of imagination.

You are a single male, a highly attractive female asks you to engage in a sexual relationship with her. However, they are already in a long-term, albeit unstable relationship. Do you accept or decline the offer? I have declined on the basis that should I accept there is a likelihood that the pleasure I would gain is less than the suffering I would cause to their partner (who I do not know) and there is a possibility I am being used to hurt their partner. From canvasing the opinion of my friends I am almost unique in my decision. Am I wrong or do I just need better friends?

I have a somewhat different take than my co-panelist. Yes: we can tag the sorts of reasons you're offering as Utilitarian, though I'm not sure that adds a lot. I'd ask a different question: are they the sorts of considerations a morally conscientious person might care about? Seems to me they are, and that seems even clearer when we put them in a plain-spoken way: you're worried that you'll hurt someone else. And you're not sure that whatever pleasure you get out of the arrangement makes up for the hurt. Whether that settles the matter or not, if your friends don't think that's relevant than maybe you do need better friends! We could ask whether you have an obligation to the woman's partner, but I worry that the retreat to polysyllaby hides the more basic point: how your behavior affects this man is morally relevant. The old-fashioned question "How would you feel if you were in his shoes?" is a perfectly good way to see that. I'm not about to offer concrete advice about this case; there's way too...

Hi, I love your website and I have enjoyed reading the articles. Please could you help me with a question? I would like to ask the question regarding 'negative numbers'. Can there be such a thing as a negative? Please allow me to explain. My daughter recently brought home some Math homework that asked what -20 + -10 =. So this had me thinking, -20 (or-10) does not exist. There is no difference between having no apples to having minus a million apples both equal me having no apples. I don't think this is the same as debt as the amount in question (as in financial debt) does physically exist, even if you owe it. My daughters teacher explained that you have to see it as a scale. But I do not feel this explains the question either. For example if a car travels one direction on a scale (say North) at 100mph, if the scale is reversed the car is not travelling minus 100mph, it is now simply travelling South at 100mph. Scale I feel is inaccurate, surly its a measure of direction along an axis i.e. left or right...

If I understand you correctly, there's a plausible point behind you question: things either exist or they don't. There's no such thing as what I'll call "negative existence" for shorthand, if that means a state that's somehow less than plain non-existence. And while there's no view so strange that some philosopher won't defend it, I'm betting most philosophers will agree: "negative existence" is a confused idea. I'm pretty sure mathematicians will be equally willing to go along with that. And since the point about negative existence seems so uncontroversial, that suggests we need to ask: when people use negative numbers, do they really mean to suggest that there's something "below" non-existence? I don't think so. Start with numbers themselves. There's a long-standing debate abut whether numbers of whatever sort exist, but we can sidestep that. There's a consistent, useful and highly successful enterprise called mathematics. From it, we learn all sorts of interesting and surprising things....

Isn't racist to find the word "nigger" racist? As in when it's merely said around you and not directed towards you. When someone calls another an "asshole," there isn't a normally a particular ethnicity that comes to mind -- yet The "N" Word is automatically associated with people of African descent. This all seems to fit into the ideology of race making racism possible.

I'll have to admit that I'm having a bit of trouble following you. In the sorts of cases that matter for this discussion, the "N" word is a slur. It's also a slur that, unlike "asshole," has a racial meaning. It's belittling someone because of their race. I think we agree on all that. The reason the "N" word brings "a particular ethnicity" to mind is because of what the word means; no mystery there. You write "yet the 'N' word is automatically associated with people of African descent" as though this was somehow puzzling or in need of explanation, but there's no puzzle that I can see. Close enough for present purposes, a racist is someone who has a negative view of some people simply because of their race or who mistreats people on account of their race. Seems pretty clear that that's bad; also seems pretty clear that there are plenty of people like that. Using a racial epithet like the "N" word is stereotypically racist behavior, and I can't see why that should seem puzzling. So what's left is...

Am I guilty of some kind of inconsistency if I reject scientific consensus about evolution, global warming, the big bang, etc., but still make regular use of modern technology?

No inconsistency. Your computer works whether you accept the quantum story that explains its microprocessors or not. You might run a risk of unreasonableness; the evidence for the things you mention is pretty good, and the same might hold for whatever gets included in your "etc." And if some of the things falling under your "etc." are routine parts of the science we use to produce the technologies you rely on, someone might wonder whether the success of those technologies doesn't give you good reason to accept the science. But consistency is not a very high bar, and though inconsistent views are arguably unreasonable, unreasonable views can be consistent.

A lecturer I met a few weeks ago said to me (among other things) that up to this point no-one has managed to disprove Kant's famous claim that 'we should always treat others as ends in themselves and never as mere means'. While I agree that this is a noble maxim by which to live our lives, is it true that it has not been disproved? It seems slightly hasty to claim this about anything.

I think there are two different issues here, so let me start with the simpler one. Suppose the lecturer said: "To the best of my knowledge—and I've read a great deal on the matter—no one has disproved Kant's claim. That seems the sort of thing one might reasonably be able to say, and might well be what the speaker meant. If so, no problem. If the speaker is claiming more or less a priori that no one has a disproof, this would be harder to swallow, but there's a way to understand it that makes it not just mere arrogance. Suppose I said: no one has disproved that 3+4 = 7. I might well mean not just that no one happens to have done this, but that no one could do it. And in fact, I'm quite sure that's right: no one could disprove it. So the speaker might have meant that Kant's claim had a status rather like "3+4=7": necessarily true, hence not disprovable. If so, I'm not sure he's right, but also not sure he's wrong. However, there's yet another possibility. To see it, ask what would count as a...

Is it wrong to fall in love and have a relationship with your first cousin even if you did not grow up together and met as adults? There are many taboos about this kind of relationships and some cultures see it as a very bad thing and others don't. I am very curious to know what philosophers have to say about this.

On the one hand, there are no doubt good reasons for incest taboos. For one thing, family life might become hopelessly complicated if sexual liaisons between first-degree relatives were common. To that we can add that when close relatives have children, the risk that their child will have birth defects goes up, and to that we can add further that if such situations became common, there might be unfortunate effects on the genetic variability of the larger population. That said, your first cousin is not a first-degree relative. Furthermore, the fact that a practice would be problematic if everyone engaged in it doesn't mean that it's automatically wrong. After all, if everyone were to practice celibacy, the human race would die out. But even if you think that would be a bad thing, you presumably don't think it means that no one should decide to be celibate. More relevantly: while it's true that when first cousins have children the risks of birth defects increase somewhat, the increase is on a par with...

Pages