On secular views, good and evil are concepts of human morality, they do not apply to non-humans, you are talking about lions as if they were humans. Even if we extended them to animals it is generally believed that they can not form intent to be held morally responsible for their actions. On religious views evil is acting against the will of God, which only creatures with free will can possibly do. Lions do not have free will (on traditional view), and them acting according to their nature is exactly according to God's will anyway.

A lion can decide whether to kill or not. A lion can like (even protect) one person and hate another. When the biblical prophet, Daniel, was thrown into a den of lions, he survived. Furthermore, lions have been kept as pets. Of course it's not advisable. There is a natural communication barrier, for one thing. And then there is the physical mismatch. (I reposted because my comment had an intolerable typo which I fixed, changing the first word only, from I to A).

Interestingly, your last argument does indeed appear in modern life. There is the concept of "duress" where someone is compelling you to do something (such as having a gun to your head), which absolves one of legal liability. Obviously legal liability is a far cry from the moral extremes of good and evil, but it does start to show the grey areas.

Do you have a context you would like us to use for determining what a "good argument" is? An argument that would satisfy a Japanese Zen Buddhist will be markedly different than one which satisfies a New York Businessman.

Why is killing evil? If you could explain that belief, it may be easier to provide a good argument.

So you would actually fault a person for committing an evil act under the threat of immediate death? That's not high philosophy, that's ignorance of psychology.

Depends on what you mean evil. I'd like some harmful animals (e.g. ones who transmit diseases) to extinct. I think world would be better without them. Thus, they are evil in my view. Evil by nature. Some people can be evil by nature as well, but some could be convinced not do something what I consider "bad", these people are not evil by nature.

Objectively, the gun invalidates the concept of choice and puts the scenario outside the realm of morality. When there is no volition, there's no morality. One can also question if an objectivist sees that her rational interest is to live in an Universe devoid of all other life. Thirdly, objectivism is about living here on earth, not about life boat scenarios.

What is the reference for your claims? It looks like you've diggen into some strange forums written by people with narrow minds... Why would eating be evil? If eating is evil, then the life itself would be evil...

Define "evil". Also, you've never met an asshole cat? You need to get out more ;)

@WordsandNumbers That's a good point to bring up. As humans we have soldiers that kill for a living yet are celebrated as heroes. Thus I think most people would agree that killing is not inherently evil.

who said a lion is not evil >:)

In addition to all the responses given so far, I would like to add that there are documented cases where animals have killed besides for merely food. For instance you can find on youtube a video documenting dolphins tearing apart a porpoise and playing a game of catch with its head. So, animals do not merely kill for food.

Are we evil because we eat chickens? Only a small minority seem to think so; it's surely a question where we will have to agree to differ. But at least we're able to discuss the matter, and vegetarians can try if they will to persuade the rest of us to conform to their ethical values. I wouldn't try persuading a lion.

Related : The Moral Status of Animals and Animal Consciousness.

Like all cats, one must only look at a lion's paws and nose and ears to know that they are not evil

"to be evil means precisely that one has evil instincts" To you, maybe. To many, "evil" means failing to overcome those instincts and failing to replace them with "good" behaviors.