Is existence a property? The way I became confounded was an example like this: a phoenix is a bird, it has feathers, and it is born from ashes, but it does not exist, whereas a penguin is a bird, has feathers, exists, and is born in snow. As in, existence and being born in snow are properties of penguins, but not of phoenixes. I feel there might be some mistake, but I certainly lack the expertise to puzzle through this on my own.

Why not think of it this way? The concept phoenix is the concept of a bird, with feathers, that arises from ashes, etc. The concept penguin is the concept of a bird, with feathers, that's (typically) born in a cold climate, etc. As it happens, the first of those concepts isn't fulfilled: nothing answers to the concept; there are no phoenixes; phoenixes don't exist. As it happens, the second concept is fulfilled: something answers to it; there are penguins; penguins exist. Both concepts exist, but only one of them is fulfilled. Our having the concepts phoenix and penguin doesn't imply that either concept is fulfilled, nor does it imply that there's any sense of 'exist' in which phoenixes (or for that matter penguins) exist.

Look at what I just read in Stanford Encyclopedia of Philosophy: "2. You could not have been born of different parents. (Someone born of different parents wouldn't be you.) (...) Each of these claims appears to have a true reading." Do you all think this way? A son of my paternal twin-uncle and my maternal twin-aunt could easily (so to say) have exactly the same DNA as I have. He could have been born on the same day. He could have been told that his parents were my actual parents. He could have been given my name. My actual parents could have had no biological child. Things in the whole world could have been exactly as they actually were and are since then. So, in what reasonable sense wouldn't this person be me?

Interesting question. Can't we interpret the story you told as one in which you never exist but someone quite similar to you does instead? Why would such an interpretation be unreasonable? You list six conditions that you seem to regard as jointly sufficient for someone's being you: (1) having exactly your DNA sequence; (2) being born on your birth-date; (3) being told that your parents are his parents; (4) being given your name; (5) your parents' having no biological child; (6) all else being equal. None of those conditions is individually sufficient for someone's being you. (1) Given identical twinning or cloning, someone else (your twin or clone) could have exactly your DNA sequence; (2) plenty of other people share your birth-date; (3) someone else could be told that your parents are his parents (and has been if you have a brother); (4) someone else could (and may actually) share your name; (5) your parents' having no biological child is certainly not sufficient for someone's being you; (6)...

Why would any one think this question is meaningful? (below) Surely morality is only objective when your current language community agree on its precepts; I don't know any atheists that would claim an "objective morality" is a viable claim beyond this, and most lean towards accepting that moral systems are contingent upon cultural norms, as such they are relative. "In conversations with Christians (and members of other religious groups), more often than not I'm asked on what grounds atheism can claim to have an objective morality. This isn't a new question, but it is one I don't feel properly equipped to answer well. I think reason and our intuitions can aid us in finding objective moral truths, but I often find myself at a loss articulating a good defense. I do not find the theist's claim that morality depends on God's existence a good one, but I want to advance a better argument for why secular morality works out, and not just knock down their view. What's the general consensus among philosophers? Is...

Your question concerns Question 4929 , which you quoted. Have a look at the Morriston and Wielenberg articles that I linked to in my answer there. In the case of Wielenberg, you have an atheist who emphatically rejects the idea that "morality is only objective when your current language community agree on its precepts." Another example is Russ Shafer-Landau ( Whatever Happened to Good and Evil? , 2004; Moral Realism: A Defence , 2004). A great many atheist philosophers think that truth in ethics isn't relative to culture or community. It's a topic of much contemporary debate, as you'll see if you search the Stanford Encyclopedia of Philosophy under "moral realism" and "moral anti-realism."

In conversations with Christians (and members of other religious groups), more often than not I'm asked on what grounds atheism can claim to have an objective morality. This isn't a new question, but it is one I don't feel properly equipped to answer well. I think reason and our intuitions can aid us in finding objective moral truths, but I often find myself at a loss articulating a good defense. I do not find the theist's claim that morality depends on God's existence a good one, but I want to advance a better argument for why secular morality works out, and not just knock down their view. What's the general consensus among philosophers? Is there a firm foundation for morality without God?

The literature on this topic is huge. Much of the work in theoretical ethics and metaethics in the last 200 years has been an attempt to provide a non-theistic foundation for morality, whether a foundation within ethics or a foundation outside ethics. If you look under "ethics," "metaethics," and "moral" in the table of contents of the Stanford Encyclopedia of Philosophy (linked in the right sidebar of this site), you'll find dozens of entries that give non-theistic treatments of ethics and ethical issues. Two good recent journal articles on the non-theistic grounding of ethics are this one by Wes Morriston and this one by Erik Wielenberg . You might also find this forthcoming paper of mine to be relevant. Best of luck in your research!

Is there a way to prove that logic works? It seems that the only two methods for doing this would be to use a logical proof –which would be incorporating an assumed answer into the question– or to use some system other than logic –thus proving that sometimes logic does not work.

Even asking "Is there a way to prove that logic works?" presupposes that logic does work at least at the level of its most basic laws, such as the Law of Noncontradiction, because the question itself has meaning only if the most basic laws of logic hold. To put it a bit differently: No sense at all can be attached to the notion that logic doesn't work (or even sometimes doesn't work). See also my reply to Question 4837 and Question 4884 . So we have what philosophers call a "transcendental" proof of the reliability of logic: If we can so much as ask whether logic is reliable (provably or otherwise), then it follows that the answer to our question is yes . You might say that this proof won't impress someone who doubts the most basic laws of logic in the first place. But I'd reply -- predictably -- that no sense can be attached to the notion of doubting the most basic laws of logic.

Is Kant's project of reconciling freedom with an apparently deterministic nature still relevant given how Quantum mechanics does not (as I understand it) see nature as a deterministic totality?

In my opinion, it's no harder to reconcile freedom (free choice, responsible action) with determinism than to reconcile it with indeterminism. On the contrary, it may be easier; see, for example, this SEP entry . According to compatibilists, we can act freely even if determinism should turn out to be true and hence even if the indeterministic interpretation of quantum mechanics should turn out to be false. But no one thinks that the truth of indeterminism (whether quantum indeterminism or some other kind) by itself would suffice to give us freedom. The debate is about whether indeterminism is necessary for freedom. In my view, incompatibilists bear the burden of showing that it is and have failed to discharge that burden.

Is it possible for a mathematical equation to both be fundamentally unsolvable and also have a correct answer?

I hope philosophers of math on the Panel will respond with more authority than I have. My understanding is that G ö del showed that arithmetic contains pairs of mutually contradictory statements neither one of which is provable within arithmetic. Assuming the standard logical law that exactly one of every pair of mutually contradictory statements is true, we get the result that some arithmetical truths are unprovable within arithmetic. I can't say whether those truths include statements to the effect that such-and-such is the solution to an equation, but if they do, and if their being unprovable within arithmetic makes the associated equations "fundamentally unsolvable," then the answer to your question is yes . Someone might reply that an unprovable arithmetical statement can't be true , but I think that would be to mistake truth for provability.

Would it be fair to say that philosophy is a manipulation of words, and that scientists deal with the relationship between language and extra-language observations? Thus "truth" would primarily be a language concept according to which consistency between words would exist. In the non-language (empirical) world truth would be infrequent because be empirical observations can rarely be one hundred percent verified.

To be candid, your question seems to embody some confusions. I'll try to address them in this reply. 1. I think it's fair to regard philosophy as the analysis (if you like, the logical manipulation) of concepts , although that view of philosophy is rejected by some philosophers. In any case, concepts can be expressed in any number of languages, so I wouldn't regard philosophy as the manipulation of words as such. 2. Scientists, as far as I can tell, don't in general examine the relationship between language and extralinguistic observations. Instead they try to explain or predict patterns of observations in as unified and elegant a way as they can manage. 3. I don't see how it follows ("Thus") from your first sentence that "truth [is] primarily a language concept according to which consistency between words would exist." First, what does "consistency between words" mean? Are "red" and "colorless" mutually inconsistent words because red and colorless are...

Would an omnipotent and omniscient being be bound by the laws of logic? If so, to what degree?

Yes. Completely. The tricky question is why . It's tempting to answer that necessarily everything is bound by the laws of logic because the alternative -- the claim that something isn't bound by the laws of logic -- is necessarily false. But, as I suggested in my reply to Question 4837 , no sense can be attached to the claim that something isn't bound by the laws of logic. So the claim can't be false , strictly speaking. Perhaps all we can assert is a wide-scope negation: it's not the case that something isn't bound by the laws of logic, just as it's not the case that @#$%^&*. Necessarily everything is bound by the laws of logic because the alternative is literally nonsense? I wish I had a better explanation!

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