I'm not sure why other philosophers dislike the notion of relative identity. I find it unattractive because (1) it's a more complicated notion than absolute identity and (2) I don't see how the added complication solves any problems or illuminates any distinctions that we can't solve or illuminate without it. Take the example you gave: two printed copies of Animal Farm . I say that those items are absolutely distinct. I take it that relative-identity theorists say that the items are identical -- one and the same individual -- qua story but not qua printed book. But why not say, instead, that the two printed books are type-identical tokens -- absolutely distinct physical tokens of a single story-type -- just as multiple distinct tokens of the single word-type "tokens" occur on the screen you're now reading? The type/token distinction is already available and independently motivated. So I see no reason to invoke relative identity in order to understand the example you gave. At any rate, the...

I agree with Prof. Stairs: even if we fix the argument's conflation of permissions and requirements, the analogies to piercings and 'R'-rated movies aren't close enough to abortion. We need to consider procedures that are of roughly equal invasiveness and seriousness. So imagine that the 15-year-old daughter needs a tonsillectomy but doesn't want one (maybe she's terrified of even routine surgery, or she's joined a religion that forbids undergoing surgery). Do her parents have the right to force the tonsillectomy on her against her will? I expect that many will answer yes . Now instead imagine that she's pregnant, and her parents judge that an abortion is in her best interests, but she doesn't want one (maybe she thinks having a baby at age 15 is in her best interests, or she's joined a religion that forbids abortion). Do her parents have the right to force the abortion on her against her will? I expect that many who answered yes to the first question will answer no to this question,...

Are there contemporary debates regarding this topic still? To judge from the SEP article on mereology, the infinite divisibility of matter is indeed a topic of contemporary debate. See especially section 3.4 here: http://plato.stanford.edu/entries/mereology. Do you think it's plausible that matter can be divided infinitely? I'd distinguish between (1) the claim that every bit of matter is composed of smaller bits of matter and (2) the claim that, as a matter of physical law, those smaller bits of matter can always be pulled apart. (1) is a logically weaker claim than (2), so (1) can be plausible even if (2) isn't. I myself find (1) to be plausible. I take no stand on (2). When we hear of experiments in modern physics where particles are collided and break into smaller pieces, does this constitute a division of matter? Yes. Or at least I can't see why it wouldn't.

You seem to be asking an empirical (psychological or sociological) question: Besides enlightened self-interest, what actually motivates atheists to behave morally? The best answer to that question will come from systematic empirical research. I don't know of any, but I wouldn't be surprised if you could find some on the web. As for what motivates particular atheists to behave morally, you might consult this collection edited by Louise M. Antony, one of the Panelists on this site. You wrote that the belief "that there is something greater than the self, of which we are a part ... seems to me only to make sense in a spiritual tradition" of the kind that atheists reject. In my reply to Question 5607 , I argued against treating the term "atheist" as implying a lack of regard for anything but gratifying one's own ego: the term simply doesn't have that implication. I see no reason why an atheist shouldn't believe that some things are worth a degree of self-sacrifice. Indeed, some philosophers...

If we are only molecules in motion and a few hundred thousand years from now, the world and history will vanish, then are our moral rules any more than the rules of a club? With all due respect to Prof. Marino, the antecedent of that question is tendentious. According to naturalism, I and a rock both consist of molecules in motion. But naturalism doesn't imply that there are no important differences -- including objectively important differences -- between me and the rock. Even though naturalism says that I consist of molecules in motion, it doesn't say that all agglomerations of molecules in motion are objectively the same: it doesn't say that I'm only molecules in motion, in the reductive sense of "only" implied by the antecedent. As to naturalism's prediction that humanity and its traces will one day be gone: Why must humanity or its traces go on forever in order for anything to be objectively right or wrong? I've never seen a good answer to that question. Several recent writers have...

Sorry to be a pest, but I still don't see how Hume escapes the problem. The claim that appeals to induction have natural force is itself an inductive claim: not a historical report of the force such appeals have had but a generalization about the force they continue to exert even on people the claimant has never met. So Hume seems to rely on the existence of a force when, by his own lights, he has no justification (not just ultimate but any justification) for believing that it exists. It looks as if Hume has to soften his critique of the justification of inductive beliefs or else stop arguing for the practical rationality of relying on induction.

If I may complicate things a bit: I don't question the scholarly accuracy of Prof. Baxter's reply on behalf of Hume, but I'd point out that he attributes to Hume a handful of inductive claims, for example: "We instinctively make and believe...predictions, anyway. We can't help it"; "People who rely on experience in this way tend to be happier and longer-lived than people who rely on other ways of coming to belief." Those are claims about human tendencies: not simply historical reports about how things have gone but inductive generalizations about how things (will) go under normal circumstances. If they were merely historical reports, we'd expect them to use the past tense rather than the present tense ("make," "believe," "rely," "tend"). Since they're inductive claims, by Hume's own lights we have no good reason to believe them. So it would seem, on this reconstruction of it, that Hume's argument for the practical rationality of our relying on induction contains premises he thinks we have no...

Because the present questioner refers to my reply to Question 5536 , I'll chime in here to clarify what I said there. My point was about the fundamentality of LNC. I wrote, "I can't see how there could be any law more fundamental than the law of non-contradiction (LNC)." I gave the following reason: "Let F be any such law. If the claim 'F is more fundamental than LNC' is meaningful (and it may not be), then it conflicts with the claim 'F isn't more fundamental than LNC' -- but that reasoning, of course, depends on LNC. " So that's why no law could be more fundamental than LNC, because LNC would need to be true before (in the sense of logical priority) the claim that some other law is more fundamental would even make sense. If someone can make sense of the claim that some law is more fundamental than LNC, I'm all ears.

How about this: All physical things occupy spacetime. But not all nonphysical things occupy spacetime, and maybe none do. The clearest example of allegedly nonphysical things would, I think, be abstract objects such as numbers and sets. Platonists say that there are infinitely many such things. See this SEP entry .

I'm not convinced that your expression "all the strawberries he does have" is a recognized way of disambiguating the expression that you say is ambiguous: "all the strawberries he has." When would we use the expression "all the strawberries he does have"? As far as I can see, only in special contexts such as this one: "He doesn't have all the strawberries in the county. But all the strawberries he does have are organic." In that example, "does" isn't used to signal the indicative mood; instead it's used merely to emphasize a contrast. Nor am I convinced that "does" + infinitive always carries existential import (i.e., implies the existence of at least one thing satisfying the verb phrase). Consider: (P) "All the intelligent extraterrestrials our galaxy does contain are extraterrestrials." Again, P will sound awkward except in a context such as this: (Q) "Our galaxy may not contain any intelligent extraterrestrials. But all the intelligent extraterrestrials our galaxy does contain are extraterrestrials...

If all that exists is matter, then what kind of property would 'value' be? If all that exists is matter, then what kind of property would any property be? I have trouble seeing how any property could itself be a material thing. A red apple is a material thing, but is its property of being red itself a material thing? Fortunately for me, not even the physicists say that literally everything is matter: there are also fields of force, states of matter, quantum vacuum states, etc. In any case, the claim that everything is matter seems to threaten not just the property of being valuable but every other property as well. If happiness, for example, is simply a mental state, no different from sadness or pain, then how can it have the property of 'value'... If happiness, sadness, and pain are all mental states, then they don't differ from each other in respect of being mental states . But that still allows them to differ in terms of whether they have the property of (positive) value....

Defenders of the possibility of time-travel usually address this potential contradiction by distinguishing between your personal time (the time kept by your biological clock) and external time (the time kept by the world's calendars). Your departure on a time-travel voyage can be future in your personal time (as well as in external time) even though your destination is past in external time (and future in your personal time). This distinction is already required by Einstein’s special theory of relativity. If you travel in a rocket so fast that your personal time passes much more slowly than external time passes for residents of Earth, you may return after one year of your personal time to find that your generation has died off: think of it as time-travel into the future. Stories about time-travel into the past also require distinguishing between these two kinds of time.