I would caution against the use of "murder" so loosely. Lions don't murder their prey. They kill their prey. Murder occurs when one entity with personhood intentional kills another entity with personhood, where personhood is rooted in the ability to comprehend reality (intellect) and the ability to make free choices among comprehended alternatives (free choice). "Murder" thus has a moral dimension that mere killing does not. Personhood is the seat of moral agency; without personhood, murder simply cannot take place, only killing, and it is a category error to ascribe moral goodness or evil to an act committed by a non-person. A spider eating another spider of the same species isn't murder; it may very well be the nature of that species to function that way.
(Entailed also by personhood is social nature. So, murdering another person is bad, because it is opposed to the very nature and thus good of the murderer. It's why killing in self-defense and the death penalty for murder are themselves mere killing, but not murder. Justice is served against the injustice of the gravely antisocial.)
From a game theoretic perspective w.r.t. just resources, murder does not generally pay especially given the social nature of a species given how antithetical it is to the social, but even if it does in some constrained sense, there is a greater intangible loss for those with personhood. Speak to almost anyone who has murdered someone. They will tell you that it changes them drastically, and not in a good way.
Why do you think that we can define personhood without much understanding of the interior life of anything other than humans? Why do you think personhood is even required for murder? Does your pet have enough of whatever makes personhood important to qualify? How about the source of your blt?
> Why do you think that we can define personhood without much understanding of the interior life of anything other than humans?
Because the "interior life" is demonstrated by observable behavior. It is nonsensical to speak of animals with a "secret rationality" that exists apart form their behavior. This would be a dualistic position that posits that these animals are two things, not one: one that is rational, the other irrational in expression. This doesn't satisfy the demands of parsimony. In fact, it isn't even coherent.
The hallmark of rationality is language, and I mean language in the full sense, not merely signaling or expression of emotional state. The descriptive and argumentative functions are what are characteristic of rationality.
> Why do you think personhood is even required for murder?
Because, as I wrote, personhood is composed of rationality - the ability to comprehend reality - and the ability to make decisions freely among rationally comprehended alternatives. If you can't understand reality, then it is nonsensical to speak of having the ability to choose freely - that's why contracts signed by mentally incompetent people are void, because rational comprehension was a missing element and thus free consent. Without the ability to choose freely, we have no culpability for our actions. We had no choice in the matter! So, a non-person can only kill, but never murder.
> Does your pet have enough of whatever makes personhood important to qualify? [etc, etc]
I don't understand what your getting at. My pet is not a person, because my pet does not rationally comprehend reality. Comprehension is not mere sensation. Animals absolutely perceive the world. They have emotions. But rational comprehension is more than sense perception and brute imagination. It is abstraction, which is to say, the formation of intensional signs - universal concepts - like "human" and "mortal" from the sense experience of particular instances which allows me to form propositions like "every human is mortal" and from there inferences like "every human is mortal / Socrates is a human / therefore, Socrates is mortal".
No other animal that we know of demonstrates these capacities, and therefore, no other animal is personal.
If you examine the interior life of a human and its behavior you will find a LOT of complexity that doesn't appear in their behavior and if you tries to run a society simulator without modeling any part of that interior life it would probably be mostly wrong because that interior life matters.
Your position that you know to what degree the interior life of the animal is simple to the point of being able to understand them fully whilst modeling none of that implies that you don't understand them or the problem.
An act is composed of object (the act itself), intent (the purpose/end motivating the act/toward which it aims) and circumstances (the context).
Thus, murder is a species of homicide. The specific differences of murder relative to homicide is that it is voluntary, premeditated, and malicious.
The law merely recognizes this distinction. It doesn't construct some convention around homicide. Indeed, law in general is a particular determination of general moral principles within a particular jurisdiction.
So, a lion doesn't commit murder, because a lion's actions are involuntary and neither malicious nor premeditated. Also, while a lion can kill a person or non-person, it is not capable of homicide, because its meaning specifically pertains to the killing of one person by another.
I think that 'hom' in homicide stands for homo so killing of (hu)man. I read your comment as lions committing homicide on hyenas which I'm sure you don't mean.
(Entailed also by personhood is social nature. So, murdering another person is bad, because it is opposed to the very nature and thus good of the murderer. It's why killing in self-defense and the death penalty for murder are themselves mere killing, but not murder. Justice is served against the injustice of the gravely antisocial.)
From a game theoretic perspective w.r.t. just resources, murder does not generally pay especially given the social nature of a species given how antithetical it is to the social, but even if it does in some constrained sense, there is a greater intangible loss for those with personhood. Speak to almost anyone who has murdered someone. They will tell you that it changes them drastically, and not in a good way.