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...

If I may: One can argue that people have morals only if they do not , in the relevant sense, "acknowledge God." I give such an argument in this chapter of a recent anthology.

This purely instrumental justification for assigning moral responsibility is typical of hard determinism, which says that, because determinism is true, agents are never morally responsible for their actions, even though society can benefit from talking and acting as if they were. One obvious objection is that it would be dishonest and unfair to treat agents as morally responsible if in fact they are not. But there is another deterministic view of moral responsibility: soft determinism. It says that agents can be genuinely morally responsible for their actions, even though determinism is true, provided that the agents (1) act from motives that they would endorse on reflection, (2) know what they are doing, and (3) are not coerced by other agents. All of (1)-(3) are compatible with determinism. For this reason, soft determinism is a compatibilist attitude toward determinism and moral responsibility. It avoids the charge that assigning moral responsibility is dishonest and unfair. You can...

As best I can tell, you may be confusing two different senses of the word "positive." When philosophers refer to your "positive" right, as opposed to your "negative" right, they typically mean your right to have some good or service provided to you, as opposed to your right not to be interfered with in some activity. So (putting it a bit simplistically perhaps) a right to adequate health care would be a positive right, while a right to speak freely in a public park would be a negative right. But philosophers also use the word "positive" to label rights that are conferred by explicit human decrees, such as rights conferred on citizens by the decrees of legislatures or courts. The contrast is often with "natural" rights, which are supposed to be rights that we possess regardless of any human decree. You seem to be saying that all of our rights are positive rights in this second sense, which -- even if true -- wouldn't imply that all of our rights are positive rights in the first sense. A legislature or...

One might ask why people would hedge the original claim, "Water is H2O," and intend to assert only the presumably weaker claim "The stuff from around here that we call 'water' has the molecular structure H2O." Is it that they don't want to identify water with the molecule H2O but merely want to assert that water is constituted by molecules of H2O? Or is it that they want to hedge against possibilities like Hilary Putnam's Twin Earth, where what the residents call "water" is macroscopically just like H2O but is in fact identical to (or constituted by) a different molecule that Putnam abbreviates "XYZ"? Either of those reasons for hedging the original claim seems to me to be too abstruse to explain the hedging (if any) done by ordinary speakers of the language. But I can't think of a third explanation. So I'm not sure how to compare this case to the assertion "Killing is wrong" or to the hedged version, "According to the normal values around here, killing is wrong." My hunch about ordinary...

Not unless ethical egoism is true. See more at the link.

The argument itself is logically valid -- indeed, formally valid. It uses only modus tollens and the rule that "P" and "~ ~ P" are equivalent, both of which are valid rules of inference. However, I think the argument is unsound -- and therefore I think it fails to establish its conclusion -- because Premise 1 is false, at least if Premise 1 is meant as a strict conditional. (I think it's also false if it's meant as a material conditional, but that's more controversial.) For excellent discussion of Premise 1, I recommend this article and this collection of essays .

I'm no expert on libertarianism in political philosophy, but I think I can answer this one: Yes. As I understand it, political libertarianism is a position concerning the legitimate power of the state. One can consistently oppose suicide on moral grounds while maintaining that the state has no business interfering with suicide. One can consistently think that, for various reasons, one morally ought not commit suicide while also thinking that the law should keep out of it. Indeed, a particularly strong distinction between "immoral" and "illegal" seems to lie at the heart of the libertarian outlook.

On this question, I doubt I can do better than to recommend to you an excellent article written by Professor Donald Hubin, available at this link: http://www.researchgate.net/publication/264974452_Empty_and_Ultimately_Meaningless_Gestures

I'm not sure that most people consider lying to be illogical even when it can produce good. More likely they consider lying to be presumptively immoral , and they allow that the moral presumption against lying is overridden in some circumstances. Take a case of the kind you described: imagine lying to a known murderer about the (nearby) location of the next innocent person he's seeking to murder. In that case, I'd agree that the moral presumption against lying is overridden by the good of protecting the innocent person. All else being equal, one shouldn't lie. But sometimes all else isn't equal. Immanuel Kant (1724-1804) is a famous philosopher who holds that lying is never morally okay: that the moral presumption against lying is never overridden. In fact, he argues that lying is illogical in a particular sense. I don't find his argument compelling, but you can learn more about it in this SEP entry ; see especially section 5.