I'm not convinced that we gain a lot here by talking about obligation; more on that below. However it's true: if you are unhealthy, then this makes at least a marginal difference to other people's health care premiums. That's one reason why it would be a good thing to try to stay healthy, even it we don't want to use the stronger language of obligation. Of course, it's just one among many reasons for trying to stay healthy, and almost certainly not the most important. Indeed, some of the other reasons (being able to care for your children, could be an example) might move us a lot closer to saying that you're obliged to stay as healthy as you can. Why the hesitation about call it an obligation? Though staying healthy is a good thing in general, there are many, many things that are each, considered one by one, possible for us, and that would make others better off if we did them. However, there are so many such things that it's not even remotely possible to do them all. This makes it pretty clear...

I have a feeling I'm not getting the intuition behind your question. Offhand, it's hard to see why random killing would be less immoral. In fact, depending on the case it could be more immoral. Suppose A, B, C, D and E are all murderous villains. While that doesn't justify taking the law onto one's own hands, there could at least be something like a moral motive behind the killings in this case. But if the victims were picked at random, killing them cold hardly be a response to any guilt they may bear. As for the difference between how a philosopher of law and an ethicist would respond, I'm afraid I have nothing to add, being neither.

I'm having trouble seeing what evolution has to do with it. Many animals, Singer supposes, feel pain. Pain (roughly; the refinements won't matter here) is intrinsically bad, no matter what sort of creature experiences it. Whether animals (or humans) feel pain because of evolution, because a God made them that way, or because we're all sentient animaldroids, designed by mad scientists from Mars is beside the point. Singer's thought is that pain is bad for us, and animals are no different from us in that respect. He isn't making a point about the phylogenetic tree. Cabbages don't feel pain; cats do. So when we're calculating the balance of pleasure to pain, the cat's pain (or pleasure) should be included in the calculation. But since cabbages aren't sentient (so far as we know), there's nothing about the cabbage to add or subtract.

First, a quibble: "murder" usually is taken to mean wrongful killing. But we can set the quibble aside. I'm inclined to turn your question around. I take it to be as plausible as any moral claim gets to be that in general killing people is wrong. Philosophers have had various things to say about why, but a bit of reflection on the fact that typically, rational people would very much prefer not to be killed should tell us something. If we agree that killing people is wrong in general, the question is why it might not always be wrong to kill people Your suggestion is that what we really care about is the "good" life, and that this is more important than mere life. Though it's more complicated than that, there's a nugget of truth there. People who favor assisted suicide, for example, may believe that not just any life is worth living, and that people shouldn't be required to live lives that only promise pain, and that they should be entitled to ask for help in ending a painful life. Whether...

There are some ethical views that would say you have a duty here. A ham-fisted version of Utilitarianism, for example, might say that you should figure out if taking the job you don't prefer would do more good overall. If so, this crude doctrine would continue, you should take that job all the same. * This is not very plausible. For one thing, the maxim asks us to calculate the incalculable. You might take the job you want less and end up burnt out only to leave it early. And since there are many ways of doing good, most of them outside the workplace, you might end up doing more good against the backdrop of a job that you love. You don't know how things will turn out. More to the point: we're obliged not to do harm when we can avoid it, and it's reasonable to think we're obliged to do some positive good, but beyond that, a good deal is up for grabs. I know of no good argument against picking the livelihood we'd like, within the bounds of decency and reason, and I'd be mightily skeptical of...

Perhaps you're putting more weight on the fable than fables are meant to bear. Fables are short, stylized ways of conveying a point, and the point here seems clear enough: if you come to be seen as a liar, you risk not being believed when it matters. Though I gather that there's a remark attributed to Aristotle that conveys much the same message, once again it may not be profitable to put too much weight on the fable as a device for exploring Aristotle's Ethics. The boy seems clearly to represent someone who lacks an important virtue: truthfulness. The fable doesn't really address the question of whether the townspeople also lack some virtue such as prudence or caution. In real life, we might wonder how many times the boy would have to lie before it become reasonable for the townspeople to ignore him; in the context of the fable, that's not really the point at issue.

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.

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...

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...

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...