1. Cows voting?
Many objections to anti-speciesism stem from a misunderstanding of what it means to reject speciesism. A common misconception is that rejecting speciesism means that all species must be treated in an identical fashion; does anti-speciesism mean that cows should get to vote? The obvious answer is no — on the contrary, anti-speciesism means that equal interests deserve equal consideration and that an individual’s species membership should not count against them. Because cows do not have an equal interest in voting (lacking the capacity to vote) they do not get equal consideration in this case. Understanding what interests humans and non-human animals possess can inform us about what rights they possess.
See David Pearce’s The Antispeciesist Revolution for further detail:
So what is the alternative to traditional anthropocentric ethics? Antispeciesism is not the claim that "All Animals Are Equal", or that all species are of equal value, or that a human or a pig is equivalent to a mosquito. Rather the antispeciesist claims that, other things being equal, equally strong interests should count equally. Experiences that are subjectively negative or positive in hedonic tone to the same degree must count for the same. And conscious beings of equivalent sentience often have equally strong interests, which (other things being equal) we must care for and respect equally - though other animals who may be less sentient can also have important interests as well.
2. Human Superiority
“But we are humans! We must look after our own species first — pigs and chickens are just animals!”
Often when we discuss anti-speciesism, we may be met with resistance where the person we are speaking to asserts that humans are superior. The simple assertion that being human grants special moral status is not an argument; it’s the articulation of exactly what anti-speciesism is calling into question. Simply saying “humans are the superior/dominant/the most valuable species” is begging the question. That is to say, it assumes what it’s trying to prove. Begging the question means one makes a claim based on evidence that requires one to already accept that the claim is true.
This passage from the Stanford Encyclopedia of Philosophy clearly explains how simply being human is nothing exceptional in regards to moral worth:
That humans are members of the species Homo sapiens is certainly a distinguishing feature of humans—humans share a genetic make-up and a distinctive physiology, we all emerge from a human pregnancy, but this is unimportant from the moral point of view. Species membership is a morally irrelevant characteristic, a bit of luck that is no more morally interesting than being born in Malaysia or Canada. As a morally irrelevant characteristic it cannot serve as the basis for a view that holds that our species deserves moral consideration that is not owed to members of other species.
3. Unique Human Capacities
Some may concede that merely belonging to the species Homo sapiens is not morally relevant. Instead, they argue it is not being human that makes us superior, but rather the capacities humans possess that make us unique and superior to other animals. For example, one may argue that humans are the most intelligent species, therefore we deserve special moral consideration. Another example may be someone who argues humans deserve special moral consideration because we have the capacity for moral reflection.
In Alastair Norcross’ paper Puppies, Pigs and People: Eating Meat and Marginal Cases, he discusses the issues that arise when the above argument is presented.
To take one of the most commonly-suggested features, many humans are incapable of engaging in moral reflection. For some, this incapacity is temporary, as is the case with infants, or the temporarily cognitively disabled. Others who once had the capacity may have permanently lost it, as is the case with the severely senile or the irreversibly comatose. Still others never had and never will have the capacity, as is the case with the severely mentally disabled. If we base our claims for the moral superiority of humans over animals on the attribution of such capacities, won’t we have to exclude many humans?
We must work to make our moral community inclusive of all who are sentient.
See Animal Ethics’ page The Relevance of Sentience for more detail.