When you say that "species...care for each other and co-operate with each other to ensure the survival of their own species," I take it you're referring not to all species (including all plants, all microbes, all invertebrates, etc.) but only to those species whose members care for each other and cooperate with each other, which may be a minority of the species that exist. Anyway, you ask whether something like the following argument is "fairly viable": 1. The members of all species [of the restricted kind referred to above] act so as to promote the survival of their own species. 2. Therefore: We humans ought to act so as to promote the survival of our own species. As you seem to recognize, the argument isn't logically valid: The premise doesn't logically imply the conclusion. But the argument can be made logically valid by inserting a premise, such as P. We humans ought to do what the members of all species [of the restricted kind referred to above] do. One problem is that P itself is highly...

You give an interesting argument that the ground of one's identity is biological rather than (just) physical and/or psychological. But it may run into a problem. Not only can one's body reject organs transplanted from someone else. It can also, in the case of autoimmune disease, "reject" (i.e., attack) one's own cells and tissues: sometimes the body doesn't "know its own." Yet it seems incorrect to say that sufferers of autoimmune disease have a "compromised" identity. Does this problem cast doubt on your proposal?

Don't forget the compatibilist account of free will (see the entry here ), which says that we can make free choices -- i.e., choices for which we're responsible (including morally responsible) and properly subject to praise or blame -- even if our choices result from totally deterministic processes. In other words, free will doesn't require the falsity of determinism. I know of no cogent arguments against the compatibilist account of free will. According to compatibilism, then, we can make free choices without needing any mysterious, non-causal, or indeterministic neurological goings-on. By the same token, an advanced AI machine could also make a free choice, provided it's advanced enough to be able to entertain, appreciate, and evaluate reasons for and against making (in its own right) some particular choice and able to choose in accordance with that evaluation. As far as I know, such machines are a long way off, but I see nothing in the concept of free choice that rules out, in principle, their...

Science also says that some of the cells in our bodies are dead. That already implies that our bodies are only partly alive, but only in the sense that not every part of our bodies is alive. If every part of a living thing must be alive, then the fact that atoms and molecules aren't alive implies that none of our cells are alive, and no bodies are ever alive. Both of those consequences are false. So we must reject the principle that every part of a living thing must be alive.

I notice that your question leaves "free will" undefined, so let me propose the definition found at merriam-webster.com: "the ability to choose how to act; the ability to make choices that are not controlled by fate or God." I presume that no one imagines that neuroscience will prove that some of our choices are controlled literally by fate or God. So if neuroscience is to show that some or all of us lack free will, neuroscience must show that some or all of us lack the ability to choose how to act or the ability to make choices. I don't think we need neuroscience experiments to show us that some people lack free will in the sense just defined: for example, people who are in the midst of drug-induced mania or a psychotic episode. To show us something we didn't already know, neuroscience would have to show that people in general typically or routinely lack free will. Some neuroscientists do claim to have shown that, but their arguments are woefully unpersuasive (in my judgment and in the...

I don't think that the theory of evolution (which I accept) provides anything like the kind of meaning that existentialists such as Camus have in mind. What is the meaning of existence according to evolutionary theory? The only remotely plausible answer I can think of is this: "To pass on one's genes to posterity, since that's what counts as success from the perspective of natural selection." But, of course, natural selection has no perspective, point of view, intentions, or goals. It's a mindless process. So that answer depends on a false presupposition. Even if that weren't true, it's highly implausible anyway that passing on one's genes could really be the meaning (or purpose) of existence. If it were, then anyone would be missing the point of existence who didn't make it his/her top priority to reproduce as often as possible, to clone his/her genome again and again, etc. But, on the contrary, someone who tried to live such a life would be pathetic. Evolutionary theory explains how species arise...

Although it is, as you say, "generally thought that all life descended from one original single-celled [organism]," the issue doesn't seem settled among the experts, as reported here . But regardless of the resolution of that issue, I'd answer no to your question. Each of the numbers you mentioned is unique. Any card in an ordinary deck is as unlikely to be drawn as any other; it's just that we arbitrarily assign special significance to particular cards, such as the ace of spades. Similarly, we may assign special significance to the number 1 or (simply because we use a base-10 system) the number 1 million, despite the fact that every number is unique. Furthermore, it's not clearly true that "all the life which exists in all the known universe seems to have arisen from one ancestor." More accurately, it's "all the life we know of seems to have arisen from one ancestor." The life we know of may constitute a small sample of all the life that exists, as yet unknown to us, in the known universe:...

I presume you're asking a normative or conceptual question, rather than a descriptive question about how healthcare systems are in fact viewed or implemented in various places. I'd answer, then, that whether ethical principles are objective or relative, universal or particular, doesn't depend on the subject matter at hand. If ethical principles depend on the place or culture (like rules of etiquette), then it seems they must be relative no matter whether they concern the ethics of healthcare or (say) the ethics of meat-eating. On the other hand, if ethical principles are true or false objectively (like statements in chemistry), then it seems they must be true or false objectively regardless of the subject matter. I can't see how there could be objective principles concerning the ethical permissibility of eating meat but only culturally relative principles concerning the ethical permissibility of aborting a fetus or euthanizing a patient. This isn't to say that objective and universal principles of...

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)...