This post is a bit long-winded. It is essentially an essay arguing against animal rights. It's long, but I think it's definitely worth reading. As you are posting in these forums, you are obviously passionate, or at least interested in this topic, and so, I think this should be a rather pertinent topic. Enjoy.

Before deciding whether animals should be granted rights, it is first of vital importance to define what rights are, and on what criteria they are granted.

Rights do not exist on their own; they are not a force of nature, like gravity or light, they do not exist in the natural world. They only exist as a construct of humans, as laws do.

Rights can exist or be created only in the minds of "persons". Persons, in the philosophical phrase, is not limited to humans, but rather, individual sapient entities. Some qualifications for being a person are the ability to think conceptually, make rational and informed decisions, to consider other individual's perspectives and their feelings, welfare, etc (be they person or non-person). All of these traits are necessary for an individual to be able to recognize the concept of rights, and act accordingly. Thus, rights are a construct of persons, and, as we are the only persons we know to exist, for all practical purposes, only humans can recognize rights.

Rights are, as I have said, not present in nature. They exist only as a construct of humans. The question then becomes, "on what basis are rights assigned?". According to Singer, because (some) animals can feel pain, they have equal interests as any other organism which can feel pain, and are thus entitled to equal consideration (ie, rights). Yet, Singer has also argued that we cannot base rights solely on an individual's capabilities or traits- their intellect, their physical traits, etc. So, assigning rights based on a trait- ability to feel pain- would be violating one of the original premises of Singer's argument.*

Aside from the moral theory of utilitarianism, there are two other moral theories which I feel could have relevance in this matter. As none of these three are accepted universally as correct, I think they should all be addressed.

The first of these is the concept of a social contract: That we are obligated not to lie, murder, etc, because if we did so, society would not function properly. We are obligated not to lie because if everyone did or could lie at any time, we would never be able to accept anything anyone said at face value. Likewise, we are obligated not to murder because if everyone could at any time do so, we would be forever distrustful of everyone: anyone could murder you whenever it served their best interests. From this idea of a social contract, we are led to the concept of rights as being contract of reciprocation: we respect the rights of others based on the unspoken promise that they will do the same in return. Without this reciprocation, rights do not exist, and so they can only exist if reciprocated. Thus, only persons can have rights, as only they can reciprocate them.

The next theory I will address is Kant's categorical imperative- more specifically, his idea of "free and rational agents". This is the concept that we are fee and rational agents- persons- and that as such, we have intrinsic value. This means that we have value in and of ourselves, and should be never be treated solely as a means to an end. An example would be- one does not rescue a person out of a river in hopes of fame, or rewards, we simply do it to save the person- we are not treating them as a means to anything else. This applies to rights in that we respect the rights of an individual simply because any free and rational agent has value, and that value must be respected- thus, they have rights.

Finally, there is utilitarianism- the assertion that all morality is based on pain and pleasure. pain is immoral, pleasure is immoral. Thus, in a moral world, we must strive to reduce pain, and increase net pleasure. It does seem self-evident that to minimize pain, we would have to abolish those things which might cause suffering to animals. However, this is not necessarily the case, as some alternatives might cause MORE pain to animals- say, the killing of cows in a slaughterhouse, and the killing of small mammals in wheat fields- neither is definitively proven to cause less deaths or harm. Could it not be conceivable that a slaughterhouse, in an ideal setting, could produce NO suffering to any cow (or, no suffering in the majority of its cows), and by using less grain overall, minimize the overall suffering? In this scenario, it would be more moral to eat meat than adopt a lifestyle where one ate meat than a lifestyle where on did not- And, if this scenario is even possible, it would nullify the idea of an animal having rights- because the more moral solution would be violating these supposed rights.

If the following arguments are true, then I feel we can arrive at only one conclusion: NONE of these moral theories (utilitarianism, Hobbe's social contract, or Kant's categorical imperative) would support the concept of animals having RIGHTS.

My personal stance on morality is somewhat of a mix- I feel that persons do have intrinsic value, and that we do deserve rights, and the only way those rights can exist over any period of time is also with some promise of reward in the future. Kant argued this reward was heaven, but I would argue that the reward is simply that of reciprocation of rights. When the concept of rights or personhood is not involved in a moral dilemma (and even sometimes when it does), then I feel utilitarianism comes into play- and THAT is where animals fit in. We are obligated to respect rights of persons, and morally obligated to minimize or eliminate pain or suffering from persons AND non persons.

Thus, my ultimate conclusion is this: Animals are certainly owed moral consideration, but are NOT entitled to rights, and further, that the concept of "animal rights" is fundamentally flawed.

*If I have any of this mistaken, please feel free to correct me.
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It would be a tragic mistake if even a small section of the Animal Liberation movement were to attempt to achieve its objectives by hurting people

-Peter Singer, founder of the modern AR movement.

It is a good essay, covering most of the bases. The term "rights" is a catch-all phrase, used and abused by human and animal rights advocates. As it is used by the masses it is frequently confused it with welfare.

You are correct that rights are granted, and not innate. Animal rights advocates feel that rights should be granted to animals for the same reasons that many folks believed in the 1860's that rights should be granted to black slaves. There have been many rights granted when there is no reciprical expectation. It's a choice, and choosing sentience for granting rights has at least as much logic to it as compared to the way that rights have been historically granted in most countries.

Animal rights advocates feel that animals have the right to their own lives, and should not be property. There has never been any consistent logic to the rights we have given, and trying to discredit the position of animal rights because it doesn't fit any previous moral guideline is simply rationalizing cruelty.

Actually, that's not true. Not all animals feel pain. Feeling pain requires, at the VERY least, neurons. Not all animals have neurons.

The definition of pain, given by the IASP (International Association for the Study of Pain) requires that, for an individual or organism to be able to feel pain, it must be able to feel unpleasant physical stimuli, AND associated emotions. This would require a complex brain and nervous system. To the best of my knowledge, only vertebrates (with the exception of cephalopods) are considered complex enough to feel emotions.