You seem to be arguing for this claim: Atheism implies that everything is morally permissible. In the view of many philosophers, myself included, that claim is false. These philosophers argue that objective truths about moral right and wrong not only needn't be God-made (or man-made) but couldn't be God-made (or man-made). I recommend reading Wes Morriston, "God and the Ontological Foundation of Morality," and Erik J. Wielenberg, "In Defense of Non-Natural, Non-Theistic Moral Realism" . On the issue of whether all laws require a lawgiver, please see my response to Question 5619 .

...how can non-being, as a concept, not have being? I see no reason why it can't. I see no reason to think that the concept of non-being (or non-existence, or related concepts) fails to exist. Not every concept must instantiate itself. Indeed, typically concepts don't instantiate themselves: the concept of tree isn't a tree, etc. It's more controversial whether being (or existence) is a characteristic (or property) of things. You'll find detailed discussion of this issue in the SEP entry linked here . I myself favor the widely held view that all (and only) things exist. It's not clear to me that this view implies that existence is a property, nor is it clear to me that anything of importance turns on whether existence is a property.

If your acquaintance argues that mandatory vaccination is immoral because it exposes people, against their will, to the risk of injury or death, you might ask her if she thinks a mandatory seat belt law is also immoral, because on rare occasions seat belts cause injury or even death. Surely it matters how likely it is that people will be harmed by obeying the vaccination law or the seat belt law, compared to the likelihood that they'll be harmed by not getting vaccinated or not wearing a seat belt. In the case of seat belts, I take it that the latter risk is much higher. I presume the same holds for vaccination. There's another factor to consider: mandatory vaccination isn't just paternalistic intervention for the sake of those getting vaccinated. It also protects others from infection, including others who can't take the vaccine because they are (known to be) allergic to one of its ingredients. So even someone opposed in principle to paternalistic laws needs another argument against mandatory...

It would, of course, be equally true that you've lost every game of chess you've ever played. Bad news to go with the good.

Just what is a definition? To answer your first question, I looked up "definition" (in the linguistic sense of the word) and got this: " define : to explain the meaning of (a word, phrase, etc.)." If that definition is accurate, then a definition is an explanation of the meaning of a word, phrase, etc. Are definitions ever proved? The definitions in dictionaries are attempts to explain the actual meanings of terms as those terms are used by the community of language-users. As such, definitions can be more accurate or less accurate, depending on how well they capture the actual way terms are used. I wouldn't say that such definitions are ever "proved," but as a matter of empirical fact some definitions are more accurate than others. Another kind of definition, not found in dictionaries, is a stipulative definition: it's just a speaker's proposal to use a word in a particular way or else the speaker's declaration that he/she will be using the word in that way. Stipulative...

I'm not sure why you regard it as a worrisome sign about current philosophy of mind that some of its practitioners take eliminative materialism (EM) seriously. At worst, it would show that some philosophers regard EM as far more plausible than it really is, but even then I don't see how that would indict current philosophy of mind as a whole. Anyway, you've asked an empirical question whose answer depends on (1) reliable data about the views of philosophers and (2) what you mean by "take seriously." I presume you mean something like "regard as too plausible to be dismissed without argument," which is a weaker attitude than "regard as plausible." I don't have empirical data, but my hunch is that most philosophers do take EM seriously in that sense, but probably because most philosophers don't regard any philosophical position as worthy of being dismissed literally without argument. At the same time, however, my hunch is that most philosophers regard EM as implausible. Curiously, the PhilPapers...

Yes. No. The time I spent defending my previous position -- against what I now regard as decisive objections -- helped me to see why a different position is more plausible, and it helped me to adopt the new position without having to worry that I hadn't given my previous position a fair shake.

If so, then just who is the jury that decides? ...then just who is right? As I see it, those two questions don't go hand-in-hand. Which side in a debate has the better reasons isn't something that a jury (in any sense of 'jury') can decide . It's not like legal guilt, which is something that a jury (or its equivalent) must decide and which isn't guaranteed to match what a fully informed and impartial observer would decide. No one is legally guilty unless a jury (or its equivalent) decides that he/she is. But one side in a debate can have the better reasons even if everyone in the audience judges otherwise. I think this point holds for debates in general, including philosophical debates. That's one reason why the oft-repeated "Who's to say?" is the wrong question to ask when debating an issue in ethics: no one's say-so is necessary or sufficient for truth in ethics or in philosophy more generally. The idea that the consensus, or even the unanimity, of an audience doesn't determine the quality...

There are relevant differences between the rapist and the fetus conceived as a result of rape. If, after the fact, the rapist no longer poses a threat to the rape victim, then the victim's killing the rapist would be revenge rather than self-defense , and we normally take very different moral attitudes toward those two types of action. By contrast, the fetus still constitutes at least a burden, and perhaps also a threat, to the rape victim, and importantly a burden or threat for which the rape victim is in no way responsible. I think it's this absence of responsibility in the case of rape that makes the most important difference. Even if we assume that the fetus conceived by rape has as much intrinsic moral status as a normal five-year-old child, that wouldn't make the rape victim responsible for the fetus in a way that obligates her to allow the use of her body for its survival. There are many five-year-old children in the world for whose survival you and I aren't obligated to make highly...

Can studying philosophy make one's life worse? Certainly it can, just as working out to get fit can make one's life worse: one who works out to get fit can thereby tear a hamstring and become laid-up and miserable, or thereby suffer a heart attack, etc. Indeed, working out to get fit can make one's life worse overall , i.e., all things considered. Ditto for studying philosophy. There's no reason to think otherwise. But studying philosophy, or working out to get fit, can also make one's life better, including better overall. For many people, myself included, studying philosophy has improved their lives overall (although I began studying philosophy because of an intense curiosity about the issues it covers rather than because of a conscious desire to make my life better by studying it). I doubt I can say anything more helpful without knowing more about your own encounters with philosophy. For instance, by "more critical of everything," do you mean "more intellectually vigilant about everything"...