I. The Test of Conscience
Sometimes, I wonder whether average human beings possess a conscience—an ability to independently judge and be motivated by moral truths—or if they instead possess only the instinctive disposition to conform to social conventions and the demands of the powerful. Most seemingly ethical behavior could be explained by such conformity—for instance, it could be that the reason why most refrain from robbing, raping, and killing other people is that those behaviors are contrary to the conventions of our society and the commands of our government. This would not require most human beings to possess a genuine conscience. The test of whether one has a conscience would have to be about whether one recognizes and is moved by moral considerations when those considerations fail to align with the social conventions, the law, or the commands of the powerful. The majority of human beings, by my read, fail that test about as badly as one could fail it.
For example, we know from the famous obedience experiments of Stanley Milgram that close to two thirds of people can be persuaded to electrocute an innocent person if ordered to do so by a man in a white coat. We know from history that large numbers of people can be induced to participate in a genocide when so commanded by their government. In our own society today, most citizens are untroubled by behavior on the part of the powerful that would outrage us if performed by those without political power: If an ordinary person forcibly extracts money from his neighbors to fund his own charity organization, that person is a thief and an extortionist; if the government does the same, it is merely pursuing normal tax policy. If an ordinary person kills large numbers of people in order to bring about some political change, that person is a vicious terrorist; if our society’s dominant group does the same, this is a standard military operation.
Those are all examples with which libertarians are familiar, and for which most libertarians can readily see my point. But the largest and most obvious example of the failure of conscience is one that many libertarians have difficulty seeing at all. It is the treatment we give to members of other sentient species. The most abject cruelty, cruelty that would horrify us if perpetrated against any other human being, scarcely troubles us when it is done to members of another species. Nearly all meat and other animal products available in the market today are produced on factory farms, under conditions that we would not hesitate to call “torture” if any human being were subjected to them. Worldwide, 74 billion animals are slaughtered for our gastronomic pleasure per year, nearly ten times the entire human population. It is a plausible guess that a decade of factory farming causes more total pain and suffering than all the human pain and suffering in history. If non-human pain is even a little bit bad, therefore, the total quantity of suffering must make this among the world’s greatest problems.
Yet many human beings see nothing wrong with this situation and—even after being apprised of the above facts—will feel no compunction as they bite into their next burger. Many others will admit that buying factory farm products is wrong, yet will struggle to find the motivation to actually modify their own behavior in light of this. Why is this? My best guess is that the vast majority of human beings are motivated to avoid moral wrongs only when those wrongs either (a) are socially disapproved, or (b) conflict with the dictates of the powerful.
But perhaps I am getting ahead of myself. Perhaps I should first explain why the treatment of other animals is a matter of moral concern. I have addressed this subject in other work, to which I refer the reader for a fuller treatment. Here, I very briefly address two questions: (1) Are animals moral subjects? (2) What duties to animals do we have?
II. Are Animals Moral Subjects?
What I mean by the first question is roughly this: Do non-human animals have experiences that are intrinsically good or bad (valuable or disvaluable for their own sake, not merely as means to something else)? The answer is obviously yes: Non-human animals such as cows, pigs, and chickens can experience enjoyment or suffering. Enjoyment is intrinsically good; suffering is intrinsically bad. Therefore, some non-human animals are subjects of intrinsically good or bad states.
How do we know that some animals experience enjoyment or suffering? Two reasons: First, they have similar physiological structures to those that explain enjoyment or suffering in us. Second, they behave as if they have enjoyment or suffering, in circumstances that would also induce enjoyment or suffering in us. Pigs, for example, have the same kind of pain sensors as you, and they squeal in pain and try to escape when stabbed, just as you would.
How do we know that pain and suffering are bad? I think that is self-evident. If someone does not see what is bad about suffering, I don’t see how I could explain it. If someone only sees the badness of his own suffering, then that individual lacks a conscience, and, again, I don’t think anything I say could remedy that. If someone sees the badness of his own suffering, and that of other people, but does not see the badness of suffering in other species, then I desire that person to explain why suffering would only be bad when felt by members of his own species. Surely that could not be a fundamental axiom; surely there would have to be some explanation for that.
The most popular answer is “Intelligence.” Your pain only matters if you’re smart. Animals are dumb, so their pain and suffering aren’t bad.
This answer is arbitrary, like the claim that pain only matters if the subject of the pain has light-colored skin, or was born in America, or can recite the Pythagorean Theorem. It also entails that the pain and suffering of human infants and mentally disabled people does not matter. This would apparently license us in torturing babies and the mentally disabled, if we smart people could obtain some small benefit by doing so. That is absurd. If your efforts to defend the status quo lead you to a defense of baby torture, and if that seems fine to you, then I would question whether you understand moral concepts.
To be clear, I am not saying that an individual’s mere failure to agree with me, or even with the correct ethical theory, shows a lack of moral concepts. I can predict that some readers are going to ascribe that to me. No, I am saying that the inability to appreciate the most paradigmatic, least controversial of moral judgments—e.g., that it is wrong to torture babies for fun—suggests a lack of conscience. It is in any case not reasonable to demand arguments against baby torture.
Some people claim that the relevant characteristic is not one’s own intelligence, but the intelligence of one’s species. Your pain matters if and only if your species is smart, whether or not you are smart. This avoids the absurdity of licensing baby torture, at the cost of taking the arbitrariness to an even greater extreme. It was not clear to begin with how intelligence is supposed to be relevant to the badness of one’s pain. But now we are supposed to think that the crucial features that make your experiences intrinsically good or bad are not even features of you or your experiences. This would be a particularly odd move for libertarians who, in other contexts, insist on the fundamentality of the individual and the moral irrelevance of unchosen group classifications.
Other theories are similarly arbitrary. Some argue that only humans possess the faculty of reason, or the ability to grasp abstract objects or universal essences. The religiously inclined may argue that only humans possess immortal souls that will join God in the afterlife. All of this, even if true, is plainly irrelevant. How would one’s ability to grasp abstract objects or to enter the afterlife have anything to do with the badness of suffering? If nominalism or atheism is true, would it follow that torture is fine?
The defenders of animal cruelty typically make no effort to answer such questions. It is as if they are simply grasping for any feature that could be said to distinguish themselves from other species, whether it be morally relevant or not, whereupon they will declare it to be an inexplicable, self-evident axiom that pain only matters if one has that feature. In the last resort, they will directly appeal to membership in the species as a crucial feature. This, I submit, is exactly what a deep-seated prejudice would look like.
III. Duties to Animals
If animal cruelty is a problem, what, if anything, ought we to do about it? I do not know the full extent of our duties, either to animals or to other humans. But I know something of our duties; I know the bare minimum that we ought to do. At a minimum, we ought to refrain from inflicting enormous pain and suffering on other beings for the sake of obtaining comparatively small gastronomic pleasures. This is a special case of the general principle that one should not cause extremely bad things to happen in order to obtain small benefits for oneself. This is not a subtle or complicated principle. This is the basic core of morality. If we do not accept that, then I don’t know why we would accept any moral principles at all.
We not only should avoid directly torturing other creatures; we also should not pay other people for such torture. One does not avoid responsibility for a wrong by outsourcing it to others. If, for example, the president hires some soldiers to torture terror suspects, the president is at least as responsible for the torture as the direct torturers. Nor would he escape responsibility if he merely tells the soldiers vaguely to “get some information” from the suspects, while knowing that the soldiers will in fact seek the information through torture. The lesson is that it is wrong to pay another person for a product, when one knows that the other person has produced the product through extremely wrongful behavior and will continue to do so as long as he continues to be paid. Thus, at a bare minimum, a person of conscience must refrain from buying products from factory farms.
We may indeed have stronger duties, both to people and to animals. Perhaps we should not purchase animal products even from humane farms. Perhaps also we must speak out against cruelty and other severe wrongs. I do not focus on such stronger duties here, as there is limited space, and I think it most important to address the most clearly wrongful behavior that almost everyone is doing on a daily basis, particularly when most seem unaware of the wrongness of this behavior.
With that in mind, I will now mention some related issues that are likely to distract libertarians.
First distraction: Do non-human animals possess rights of the same sort as individual human beings? This is an intellectually interesting question, but it is not the best question to focus on now, for a number of reasons. One reason is that, in general, adequately addressing the topic of rights requires long and involved theoretical discussions, discussions many times longer than the word limit for this piece. Another reason is that, even after such long and involved discussions, hardly anyone will have been persuaded of any important conclusions. I know this because I have plenty of experience with such discussions among libertarians and philosophers. (This is partly because most libertarians and philosophers are absurdly overconfident about abstract generalizations. They will cling with dogmatic certitude to the first vaguely plausible speculation they think of, then reject any proposition, however obvious, that comes along later. But I digress.) A final reason is that, fortunately, the largest practical issues can be resolved without discussion of rights. Without mentioning the notion of “rights,” we can see that pain and suffering is bad, and that one should not cause an enormous amount of something bad solely for the sake of obtaining comparatively small benefits for oneself. Those points are enough to see that the behavior of the overwhelming majority of people is morally wrong.
Second distraction: What should be the government’s policy regarding the treatment of animals? Though this, too, is intellectually interesting, it is not the optimal question to focus our attention on. Again, an adequate treatment would require lengthy and involved discussion of political philosophy, which would produce no agreement. Again, however, the most practically important question for us as individuals—what we ourselves ought to do—can be addressed without resolving the public policy question.
Third distraction: Are the most extreme animal rights positions defensible? On this issue as elsewhere, human beings have a strong temptation to focus on our most extreme intellectual opponents. But, here as elsewhere, the rational approach is to focus on the most reasonable and difficult-to-answer positions that are contrary to one’s own. For example, in order to argue that most people are acting very wrongly on a regular basis, it is not necessary to claim that non-human animals have the same rights as humans, nor that their interests matter exactly as much as human interests. If animal suffering were even one thousandth as important as (qualitatively similar) human suffering, factory farming would still be among the most serious problems in the world today. (Imagine that 74 million humans were being tortured in factory-farm-like conditions each year. Unquestionably, this would be among the world’s greatest problems.) Therefore, a rational interlocutor, if he disagreed with my central contention, would focus on explaining why non-human animal suffering is not even a thousandth as bad as qualitatively similar suffering by humans.
V. Commitment to the Good
I am a committed libertarian. Yet my first commitment is not—nor should yours be—to libertarianism. Our first loyalty, as human beings, must be to the good and the right. Members of other sentient species on the Earth may not possess the same liberty rights as human beings (that is a matter for debate), and thus the ethical treatment of these other creatures may not be addressed in a distinctive way by our political ideology. Their mistreatment may also fall outside the range of what our society presently condemns or punishes. But it most certainly is possible to treat these other creatures wrongly, and when such wrongful treatment occurs on a massive scale, a scale to dwarf any suffering by our own species, that should be a matter of concern to all rational beings, libertarian and non-libertarian alike.
 See Stanley Milgram, Obedience to Authority: An Experimental View (New York: Harper, 2009).
 For discussion, see Michael Huemer, The Problem of Political Authority (New York: Palgrave Macmillan, 2013).
 On the conditions in factory farms, see Stuart Rachels, “Vegetarianism,” pp. 877-905 in The Oxford Handbook of Animal Ethics (Oxford Univ. Press, 2011), at pp. 877-83, available at www.jamesrachels.org/stuart/veg.pdf. On the number of animals slaughtered per year, see U.N. Food and Agriculture Organization, http://www.fao.org/faostat/en/#data/QL, accessed Sept. 5, 2018. By recent estimates, about 107 billion people have lived in the history of the Earth; see Wesley Stephenson, “Do the Dead Outnumber the Living?”, BBC News, February 4, 2012, https://www.bbc.com/news/magazine-16870579, accessed Jan. 22, 2020.
 See especially my Dialogues on Ethical Vegetarianism (New York: Routledge, 2019). (This book is an improved version of the article “Dialogues on Ethical Vegetarianism,” Between the Species 22 (2018): 20-135, available at https://digitalcommons.calpoly.edu/bts/vol22/iss1/2/.) See also my contribution to Michael Huemer and Daniel J. D’Amico, “Debate: Libertarians Should Be Vegetarians,” Reason, October 2018, available at https://reason.com/2018/09/26/proposition-libertarians-shoul1/, accessed January 20, 2020.
 This is the situation of psychopaths, who are essentially incurable; see Robert D. Hare, Without Conscience: The Disturbing World of the Psychopaths Among Us (New York: Guilford Press, 1999).
 See Bryan Caplan, “Reply to Huemer on Ethical Treatment of Animals (including Bugs),” Econlog, Oct. 11, 2016, http://econlog.econlib.org/archives/2016/10/reply_to_huemer.html; “Further Reply to Huemer on the Ethical Treatment of Animals,” Econlog, Oct. 14, 2016, http://econlog.econlib.org/archives/2016/10/further_reply_t_1.html.
 See Richard Posner’s contribution to “Animal Rights” (debate between Peter Singer & Richard Posner), Slate, June 2001, available at https://www.utilitarian.net/singer/interviews-debates/200106—.htm.
 Nominalism is a position in metaphysics that denies the existence of abstract objects.