In my work I have repeatedly pointed out two things about what philosophers think the options are in developing a theory of moral truth: (1) that their standard assumption of only three options (consequentialist, deontological, and virtue ethics) curiously omits a fourth of equal importance, the only one developed by a woman, and (2) that these are actually all the same ethical theory and the fact that no one has ever noticed this is very annoying, and impeding progress in moral philosophy. Today I’m going to outline why both points are true, and matter a great deal. Philosophy will forever remain stuck and getting barely more than nowhere, until it acknowledges and integrates both facts in all future analysis of this question: What moral propositions are true?

The Moral Theory Debate

In broadest scope, the moral theory debate can be divided into two general camps, those who think there is no discoverable moral truth (e.g. nihilism, skepticism, emotivism, prescriptivism, etc.) and those who think there is. I’ve written extensively before on why there necessarily must be moral truth, and it is empirically discoverable. You needn’t trouble with the proof now, but if you wish to, see [1]. Here I will take that as assumed and discuss what then.

Philosophers who teach theories of moral realism most commonly claim (and especially in introductory courses and articles nearly always claim) that there are three incompatible theories of moral truth under that umbrella. You can see this in the Internet Encyclopedia of Philosophy entry on “Ethics” and the Stanford Encyclopedia of Philosophy entry on “Virtue Ethics” (both peer reviewed resources written by professional experts, they will be referenced heretofore as the IEP and the SEP).

These three theories are:

Consequentialism: Moral truth is a function of what behaviors produce the best consequences. The question then becomes “What are the best consequences?” Once you’ve worked that out, “What behaviors best produce those consequences” becomes a straightforward empirical question. There are two general versions of this, based on the question “Consequences to whom?” The most widely pursued is the tradition of utilitarianism sort of formalized by John Stuart Mill (d. 1873, in actuality various forms of utilitarian ethics precede him, even by thousands of years, but he is the first to frame up the category in the form subsequently debated). Utilitarianism now comes in many debated varieties—it has long since advanced well beyond Mill’s original conception. But two general classes of it are ethical egoism (whereby consequences to the moral agent are the deciding factor: the IEP and the SEP both have entries) and ethical pluralism (whereby the consequences to everyone, or at least some public group, is the deciding factor: the IEP and SEP both discuss this under consequentialism).

Moral truth is a function of what behaviors produce the best consequences. The question then becomes “What are the best consequences?” Once you’ve worked that out, “What behaviors best produce those consequences” becomes a straightforward empirical question. There are two general versions of this, based on the question “Consequences to whom?” The most widely pursued is the tradition of sort of formalized by (d. 1873, in actuality various forms of utilitarian ethics precede him, even by thousands of years, but he is the first to frame up the category in the form subsequently debated). Utilitarianism now comes in many debated varieties—it has long since advanced well beyond Mill’s original conception. But two general classes of it are (whereby consequences to the moral agent are the deciding factor: the and the both have entries) and (whereby the consequences to everyone, or at least some public group, is the deciding factor: the and both discuss this under consequentialism). Deontology: Moral truth is a function of what behaviors are intrinsically the best, irrespective of consequences (in some sense). It is often described as a theory based on moral duty, or wherein the rightness of the act derives from the nature of the act itself, or what sort of person you become in acting as you do (the SEP has an entry; the IEP covers the subject within its entries on Kant and Natural Rights Theory ). The most seminal formulation, which has become foundational to all subsequent variations, is that of Immanuel Kant (d. 1804). He developed the concept of morality as that which is entailed by a categorical imperative , as distinct from hypothetical imperatives (which everyone who knows what they are talking about knows are empirically testable propositions). One example of how it supposedly differs from consequentalism is that deontologically, killing innocents can be wrong even if some greater good can come of it, a conclusion consequentalism might struggle to justify.

Moral truth is a function of what behaviors are intrinsically the best, irrespective of consequences (in some sense). It is often described as a theory based on moral duty, or wherein the rightness of the act derives from the nature of the act itself, or what sort of person you become in acting as you do (the has an entry; the IEP covers the subject within its entries on and ). The most seminal formulation, which has become foundational to all subsequent variations, is that of (d. 1804). He developed the concept of morality as that which is entailed by a , as distinct from hypothetical imperatives (which everyone who knows what they are talking about knows are empirically testable propositions). One example of how it supposedly differs from consequentalism is that deontologically, killing innocents can be wrong even if some greater good can come of it, a conclusion consequentalism might struggle to justify. Virtue Ethics: The oldest, fully-developed formal theory of moral facts is that of Aristotle. It similarly drove variants in other moral philosophies of antiquity, such as Stoicism (Epicureanism was consequentialist, and involved some of the earliest social contract theory justifications of morality). Though Stoicism resembled deontological theories more than is sometimes noted, it did so around the model of embodying moral virtues. Aristotelianism, by contrast, was actually ultimately consequentialist, but again through the model of embodying moral virtues. In this theory, morality consists of those behaviors that are entailed by the best virtues of character. It is distinguished both in emphasizing the need to cultivate habits of character (and thus not just following rules, consequentialist or deontological) and in its casuistic situationalism: moral truth derives not from rules but from the combination of the particular situation one faces and the best virtues guiding action in all situations.

Sometimes what will be suggested as a fourth theory is some form of Social Contract Theory (see entries at IEP and SEP). Christian apologist William Lane Craig was most famously defeated by it in a debate with philosopher Shelley Kagan. However, SCT is always framed as either a consequentialist or deontological theory (and could be alternatively framed as a consequence of virtue ethics). It needs to be, since it has no justification without some underlying theory of why we should follow the social contract, and answering that question always throws us back into the three ways of doing that usually laid out above.

But what should be a fourth theory, the equal of the standard three and required in any introduction to moral theory (notably also as it can serve as justifying foundation for SCT, thus similarly illustrating its precedence to it), is the one developed by one of the most important women philosophers of the 20th century: Philippa Foot. Her theory was that morality is not as Kant thought contrary to hypothetical imperatives but in fact actually a system of hypothetical imperatives. This is summarized by Nick Papadakis at Analysis, but her famous paper on the subject can be found online and in one of the best reference collections on moral realism: see [2]. Spoiler: I think she is right. My article in [1] formally proves her case.

These Are All the Same Theory

I have made this point before: see [3]. But never in a single place and in clear enough fashion to make the point obvious. So that’s what I’ll now do.

What will become clear shortly is what I proved in my peer reviewed chapter in The End of Christianity (see citation in [1]): that Kant’s categorical imperative reduces by his own reasoning to a hypothetical imperative (pp. 340-41), and since all hypothetical imperatives are consequentialist, any deontology that has a plausible claim to being true (pp. 342-43) always reduces to consequentialism, and consequentialism in turn always entails virtue ethics (p. 424 n. 26), and vice versa, by the following reasoning:

Virtue theory of ethics has the most scientific support [source] (modern social contract theory still explains the evolution of most human moral reasoning [source], but such reasoning still assumes the primacy of associated virtues), and is thus what I defend elsewhere, but virtue theories still reduce to a system of foundational imperatives (e.g., “you ought to develop and cultivate the virtue of compassion”), from which follows a system of occasional imperatives (e.g., “if you are compassionate, then you ought to x in circumstance z“).

I’ll unpack that shortly. But first let’s settle the claim about all true deontologies collapsing into consequentialism and all true consequentialisms collapsing into deontology.

Deontology Reduces to Consequentialism

Kant’s first formulation of the categorical imperative remains the most familiar: “Act only according to that maxim whereby you can at the same time will that it should become a universal law without contradiction.” His other two formulations are just attempts to build on the first formulation in different ways.[4] In short, the morally right act is that act you would gladly wish everyone perform. But on what basis do you decide what behaviors you would wish to be universal? Well, guess what. Consequences. You are thus, when following a categorical imperative, actually covertly engaging in consequentialism.

And there is no avoiding this. It is logically impossible to decide what laws to wish universal without any context as to what such a universalized behavior will do (to you, and the world). It is always decided in reference to that context. It is thus always decided in reference to consequences. This is even true in Kant’s desperate attempt to avoid this with his second formulation (see [4]), since he has much to say about how important it is that we not treat others or even ourselves as only a means to an end, but in every case he appeals to consequences in arguing that point. They might be different consequences than utilitarians talk about, but that just means Kant was noticing consequences they were ignoring: consequences like what sort of person you become when you act a certain way (and thus the consequence of how that will make you feel, how that will impact your happiness, how that will influence others’ behavior, and so on). Kant’s argument against suicide is full of covert appeals to how it would make you feel if you realized the significance of what you were doing. That’s an appeal to consequences.

This is more obvious if Kant was wrong: if we didn’t care about any of the consequences he appeals to, we would have no basis for willing his ban on suicide to be a universal law. And guess what? Kant was wrong. His claim that suicide never treats a person as an end in themselves is manifestly false, since alleviating someone’s intolerable misery is precisely that which Kant regards as laudably treating a person as an end in themselves. One can only apply Kant’s argument to those suicides contemplated in the absence of any such end (e.g. when the misery is not actually intolerable or inescapable, or doesn’t even exist, being only a product of the imagination, or a false apprehension of future events), and it becomes apparent why: the consequences then are not what we would will to be universally sought. But those of us who see clearly, do indeed see the option of suicide as sometimes what we would indeed will to be a universal law (e.g. the liberty of the individual to choose medical euthanasia or heroic death: Sense and Goodness without God, pp. 341-42 = V.2.3.1). And we do so precisely because it accepts persons as ends in themselves: their wishes and dignity, reflected in their own exercise of autonomy, with full and rational cognizance of the truth of their situation and the differential consequences of their choosing to act or not to act.

Some have attempted to claim Kant’s categorical imperative admits of no exceptions, and this is what distinguishes it from consequentialism, but that is not logically true. For example, I can will to be a universal law that no one kill except in self-defense. This satisfies the categorical imperative as stated. Kant denied this, but on no logical ground. Because exceptions are themselves universal laws: they can be willed into existence by the same categorical reasoning. In fact exceptions are built in to every rule derived by his categorical imperative. Though Kant was absolutely against killing, many have claimed they’d will to be a universal law that one not kill innocents. But that is simply a disguised exception: “one shall not kill anyone except the non-innocent.”

And metaphysically, it’s exceptions all the way down. “One shall not kill, except people who enjoy being killed because they are instantly resurrected even healthier and happier.” It just so happens that that isn’t an actual consequence. But it contingently could have been. And it will be someday (e.g. when we all live in fully programmable virtual realities a million years from now). This reveals the fact that not only is the categorical imperative actually consequentialist, but its consequentialism is circumstantial. It is simply overlooked that the fact that killing someone is permanently destructive is a contingent fact of our being accidentally evolved biological organisms. If we were indestructible gods, who always rise from the dead in better health and actually desired that, “thou shalt not kill” would not be a categorical imperative anymore. It would be as trivial and permissible as stopping someone’s heart to surgically repair it with their consent. An act routinely performed every day around the world.

And this leads us to the hidden secret of all plausible deontologies: to be true, they must appeal to reasons we have to obey them (otherwise, we have no reason to obey them, and they are therefore no longer true, in any sense that commands our concern: TEC pp. 342-43), but those reasons will always consist of an appeal to consequences (because all desires are by definition an interest in certain consequences: the consequences being desired: TEC pp. 340-41). Therefore all true deontologies reduce to consequentialism. As I wrote of Kant’s case in particular (TEC p. 340):

Kant argued that the only reason to obey his categorical imperatives is that doing so will bring us a greater sense of self-worth, that in fact we should “hold ourselves bound by certain laws in order to find solely in our own person a worth” that compensates us for every loss incurred by obeying, for “there is no one, not even the most hardened scoundrel who does not wish that he too might be a man of like spirit,” yet only through the moral life can he gain that “greater inner worth of his own person.” Thus Kant claimed a strong sense of self-worth is not possible for the immoral person, but a matter of course for the moral one, and yet everyone wants such a thing (more even than anything else), therefore everyone has sufficient reason to be moral. He never noticed that he had thereby reduced his entire system of categorical imperatives to a single hypothetical imperative.

Kant made it all about an end (a consequence) we all want, and want more than anything else. He thus couldn’t even justify his categorical imperative without covertly hiding the fact that it was a hypothetical imperative all along.

The same will follow for any other purported version of deontology. Either there will be no reason to obey it (and thus it will be literally false, i.e. it will not truthfully describe how anyone ought to behave), or it will collapse back to consequentialism. And it will do so through precisely that channel of the reason to obey it: which reason is and will always be the consequences of adopting it. Philosophers ought therefore to stop acting like deontological ethics are not consequentialist, and start exposing the actual consequences being appealed to in every appeal for any deontological conclusion.

Consequentialism Reduces to Deontology

A common example that is supposed to illustrate how deontology gets a different result than consequentialism is that deontologically we ought not kill the innocent for any reason, whereas consequentialism supposedly entails that we should kill the innocent whenever a greater good results. But this is a hopeless confusion. The error is in assuming there is a good that results from the killing of innocents that is greater than the good that results from leaving them alive. The error, in other words, lies in misidentifying something else as “the greater good.” And in fact that is all deontologists are actually saying (generally unawares): that there is always greater good in not killing innocents than in any other consequences of doing so. In other words, deontologists and consequentialists are really just arguing over which consequences matter more than others. They are simply all consequentialists disagreeing on what the greater good is.

So there is no fundamental distinction here. It’s consequentialism all the way down. But there remains the actual dispute, which differs from the dispute these philosophers think they are having. The actual dispute is: What is the greater good we should be pursuing? Kant argued it was a feeling of “a greater inner worth of our own person” that comes from being a certain sort of person (who acts a certain way and cares about certain things). If he was right, then his version of consequentialism, his utilitarianism, would define acts that produce “a greater inner worth of the moral actor’s own person” as the end justifying all means. Kant’s utility function was simply “feeling a greater sense of inner worth that comes only from being a certain sort of person in our actions.” For example, the sort of person who just doesn’t kill innocent people. His hypothesis was that we will feel better about being that sort of person than about being any other—like, say, the sort of person who would dispose of innocent people to gain some other end.

Of course, Kant would say, that this is what will be the case when we are fully aware of who we are and what we’ve become and what that means in terms of consequences to ourselves and others—many a delusional person will be ignorant of these and thus continue to make bad decisions falsely believing them to be good ones. And I agree. Moral truth cannot follow from a false accounting of the facts. Therefore, moral truth is what follows from the true account of the facts, even if we are not yet aware of what that is. But this can be as true of Kant’s own account as anyone else’s. And in fact, it largely is: Kant was wrong about a lot. His conclusions in moral theory are therefore also wrong—as in, factually false. The higher level point is true—who we become in our actions and how a fully aware person will feel about that is a consequence that can supersede all other consequences—but the derivation is not: sometimes, it might be moral to kill innocent people.

On full analysis, projecting the differential consequences to our feeling of self-worth for each available choice, (A) killing innocents to (for example) save a greater number of innocents or (B) not killing those innocents and thereby letting even more innocents die, might actually lead us to a greater contentment with ourselves if we choose (A). Which would then mean that (A) is actually what’s right by Kant’s own reasoning. After all, we can easily imagine willing that to be a universal law. Even on self-interest, since our chances of dying are greater if we allow smaller groups to be saved at the expense of larger, since statistically we will more likely find ourselves in a larger group. This has of course been studied scientifically. It is known as the Trolley Problem (incidentally first formulated by, guess who…Philippa Foot). And the findings don’t back up Kant as much as his theory requires. Kant needs everyone to agree which decision makes them more comfortable with themselves. But that is not what we find. In fact, when faced with the dilemma, most people kill the few to save the many.

But this only illustrates that any fully realized consequentialism (and thus any consequentialism that is actually based on all the facts) will be far more complex than simplistic utilitarians have imagined. And thus, deontological thinking has valuably called attention to consequences utilitarians have typically overlooked and thus not accounted for. One example relates to variants of the Trolley Problem in which, covertly, the scenario becomes one in which a Duty of Care has entered in. Duty of Care is a legal term in tort law. But it actually reflects a moral reality, which on the surface is deontological (it is, after all, called a “duty” of care), but in actuality is consequentialist, as revealed when analyzed through the lens of Social Contract Theory (which reduces to Game Theory, but that’s an argument for another time: see [5]).

For example, one of the Trolley variants is the Transplant Problem, developed by Judith Jarvis Thomson:

A brilliant transplant surgeon has five patients, each in need of a different organ, each of whom will die without that organ. Unfortunately, there are no organs available to perform any of these five transplant operations. A healthy young traveler, just passing through the city the doctor works in, comes in for a routine checkup. In the course of doing the checkup, the doctor discovers that his organs are compatible with all five of his dying patients. Suppose further that if the young man were to disappear, no one would suspect the doctor. Do you support the morality of the doctor to kill that tourist and provide his healthy organs to those five dying persons and save their lives?

Transparently this looks just like the Trolley Problem and exposes the horrors that deontologists claim consequentialism leads to and which deontology avoids. Though that’s false: any consequentialist argument for murdering the hapless patient can be reconstructed as a deontological argument to the same conclusion—since what we will to be a universal law is actually based on the consequences we want, so if we wanted the consequences of saving five lives at the cost of one, then killing the patient would even be deontologically correct behavior. The deontologist can only object by appealing to consequences that are worse—thus admitting that they are really consequentialists after all. But in this they would be right. And this is why deontologists have been looking at a piece of consequentialism that the self-described consequentialists have been ignoring. Unifying both views is the only way to produce a valid consequentialism. In essence, both groups are looking at the exact same theory from different angles and thus, due to perspective, seeing different things. What they don’t realize is that they are both not seeing the whole picture. And if they did, they’d end up completely agreeing.

Here is why. If it were a universal law that single patients attending hospitals can be killed to save five, no one would ever go to hospitals. The social consequence of this would be vastly worse than letting the five patients die. This is why Duty of Care exists as a concept. For social systems to function, we need certain duties to be followed (generally, those that allow people to be assured of their safety in various respects when performing certain actions that are necessary to their lives or happiness or those of others—otherwise, they wouldn’t do those things—or would take socially disruptive measures to do so, e.g. any lone patient entering a hospital will bring guards to hold the doctor at gunpoint to ensure his safety, creating a huge drain on the economy, increased fear, and an increased risk of bad outcomes). This is a greater consequence that consequentialists all too often overlook in their supposedly studious math.

Notably, no such Duty of Care exists in the original Trolley Problem: implicitly, no one in that scenario has any reason to expect their life to be preferred over anyone else’s by the rail switch attendant. Why? Because we are compelled by logical necessity that this be a universal law. There is no way, without self-contradiction, to say one switch position is better than the other based on any duty of care to the smaller group, since the duty of care for them is the same as for the larger group, and so all things thus equal, what remains to decide the correct decision is what remains: how many die. We are thus compelled even by deontological reasoning to kill the fewest. Kant did not foresee this.

Besides these, there are many other respects in which a full-fledged consequentialism actually ends up entailing every preferable conclusion of any deontological ethical system. Duties are morally compelling because of the wide social consequences of not obeying them. Consequentialism thus collapses to deontology, in respect to anything deontology ever had to offer. Philosophers ought therefore to be analyzing every deontological conclusion they think is sound so as to expose what consequences actually make it morally preferable to what any incomplete consequentialism seems to entail. Notably, some philosophers have been doing this without even knowing it: it’s called rule utilitarianism. But overall, instead of just saying some deontology entails you do x, do the hard work of asking yourself why you really think doing x is consequentially better. Because really, you do. And it is doing philosophy no service to ignore the consequences you are preferring and why.

And They Both Reduce to Virtue Ethics

If a certain set of behaviors is morally right (as both deontological and consequentialist theories assert), then it is by the same reasoning morally necessary to cultivate those habits of character that will make those behaviors common, consistent, and easy to perform. Any categorical imperative will in turn entail this, as will any consequentialist imperative.

Deontologically, if you will something to be universally performed, you are de facto also willing that people cultivate those virtues that will produce this universal behavior. Because “I would will that everyone behave thus” entails “I would will that everyone cultivate those moral virtues that will cause them to reliably behave thus.” It would be self-contradictory not to. And the categorical imperative rules out self-contradiction. The same reasoning will follow for any coherent deontological system that has any claim to being true. The fact that Kant and later deontologists didn’t think this through so as to notice it is just another example of the same blindness that caused consequentialists to fail to see the kinds of consequences deontologists didn’t realize they were arguing as more important.

Consequentially, if you want the greatest good, you need to accept those behaviors that produce it, and that therefore must include behaviors that produce the character that produces those behaviors (more commonly, consistently, and easily). Thus, virtue ethics is entailed by consequentialism as well. It is only the more pertinent that science has established the needs of this: moral behavior only reliably issues from persons who have fully habituated moral virtues (such as compassion for others, a passion for honesty and reasonableness, etc.). Systems of rules are simply ineffectual, unless moral agents feel naturally inclined to follow them. And that requires cultivated virtues.

And the reduction goes both ways. Deontological and consequentialist ethics reduce to virtue ethics, as just demonstrated. And virtue ethics reduces to deontology and consequentialism. The justification for virtue ethics (that which motivates anyone to obey it) has always been explicitly consequentialist: the production of personal happiness, or more precisely that state of contentment with oneself and one’s life Aristotle described as eudaimonia (which is egoist, but Aristotle also implied a non-egoist consequentialism: society will function better for everyone if the members of that society live by moral virtues). Deontologically, a justification for virtue ethics arises from the same fact that reduces deontology to virtue ethics: you would will to be a universal law that everyone live by moral virtues. Deontological ethics has long been about what sort of person you become in the act (as opposed to ignoring that and focusing solely on the external consequences of the act), so it is surprising no one realized that “who you become as a person” is quite simply virtue ethics.

Philosophers therefore should abandon an exclusive focus on moral rules and recognize that moral virtues must also be fully integrated into any true moral theory. Virtue ethics can no longer be treated as a side option. It is fully a component of any valid consequentialist or deontological ethics. Not surprisingly both, as they reduce to each other.

And It’s Hypothetical Imperatives All the Way Down

Social Contract Theory emerges from any deontological, consequentialist, or virtue based moral system when placed in contact with the reality of social systems. So given that deontological, consequentialist, and virtue based moral systems are all actually in fact the same one system, just looked at from different angles, it is easier to see that SCT is also an inalienable component of any true moral system. We already saw a taste of that fact in our realization of how prima facie deontological duties of care emerge from consequentialism.

But one other thing you might have noticed by now is how often hypothesis has come up in every part of this discussion, explicitly or implicitly. Kant’s moral philosophy was a system of hypothetical imperatives—not only did we show his categorical imperative was in fact a hypothetical imperative, but all his derivations of moral rules were heavily built out of hypotheses: about what people want, and what certain behaviors will cause, in them and to others, such as whether it will cause people to be treated as means and not ends and what the consequences of that will then be to them and to society. The same holds, again, for any deontological system that has any plausible claim to being true. Because, as shown, it’s consequentialism all the way down.

But consequentialism is fundamentally a system of hypothetical imperatives. It’s all about what consequences are to everyone most desirable (the definition of the greatest good), which is the condition component of a hypothetical imperative; and the actions that will produce those desired outcomes are the consequence component. Virtue ethics likewise: if you want above all things eudaimonia, or a greater sense of self-worth, or to live in a just and functional society, or anything else (or a collective of things) that can only be reliably realized through cultivating certain moral virtues, then virtue ethics itself becomes a system of hypothetical imperatives. If you want the outcome, then you ought to do what will produce it. Which in this case means the virtues of character that will more reliably cause in you the behaviors that will generate that most desired outcome.

There is a great deal more to everything, of course. The details of what’s moral and of what are moral virtues, for example. Or the complexities of different circumstances. And how we integrate unavoidable ignorance into sound decision-making. And pedagogy: what people ought to do, and what will convince them of that, are very different things. Likewise, consequences to add up don’t just include inner worth and external effects, but also states like joy and security and contentment (in yourself, and in others), which often depend on respecting such personal goods as autonomy and privacy. And what we happen to desire most right now, could well be completely not what we would desire most if we reasoned logically from true facts instead of reasoning fallaciously from false beliefs—and moral truth can only follow from factual truth, which means our “greatest desire” from which all moral truth follows is only the second of these desires: the one you would have if you were logical and informed. You therefore ought to be pursuing what that is. Which is a categorically and consequentially true fact about you. It only remains for you to realize it.

-:-

Notes

[1] That true moral facts exist: Moral propositions are imperatives that supersede all imperatives (by definition and practice, that is what everyone always really means by an imperative being a moral imperative as opposed to some other); hypothetical imperatives are well recognized as verifiable and falsifiable empirical propositions, and many have in fact been proved objectively true (e.g. best practices in surgery, agriculture, engineering, are all systems of hypothetical imperatives, many of which have been proved true by empirical means, refuting the claim that there is an absolute dichotomy between is and ought—there isn’t; get over it; and be thankful, because it’s the only thing that keeps bridges up in an earthquake or you alive in the surgical theater); hypothetical imperatives are by definition conditional propositions whose condition is a desire for the consequence; greater desires supersede lesser (a material fact); greatest desires exist (a material fact); therefore there are imperatives that supersede all other imperatives, and which are factually true (for each moral agent a greatest desire actually objectively exists, as do best practices to realize the consequences thus desired). All that remains is to determine what the greatest desire is (an empirical question) and what will obtain it (also an empirical question). For the formal syllogisms and peer reviewed defense of this argument see: Richard Carrier, “Moral Facts Naturally Exist (and Science Could Find Them),” The End of Christianity (ed. John Loftus: Prometheus 2011), pp. 333-64, 420-29 (formal proofs: pp. 359-64).

[2] Philippa Foot on moral theory: Philippa Foot, “Morality as a System of Hypothetical Imperatives,” The Philosophical Review 81.3 (July 1972), pp. 305-316, reproduced in Moral Discourse and Practice (ed. Stephen Darwall, Allan Gibbard, and Peter Railton: Oxford University Press, 1997), pp. 313–22. She took a different tack later in life with an argument in Natural Goodness (Oxford University Press, 2001), although one not incompatible with her more well-known proposal, that moral facts are natural facts about Homo sapiens as a species. There is a general and chapter-by-chapter summary at the publisher’s website, and some thoughtful analysis of this (more fundamental) view by Brook Sadler in Essays in Philosophy 5.2.28 (2008), and by Peter Eichman in “Thoughts as Data, Thoughts as Code: Natural Goodness and a Model of the Will” (2007).

[3] My previous notice that all moral theories are the same: In Sense and Goodness without God: A Defense of Metaphysical Naturalism I developed colloquially and at length the moral theory I more formally and succinctly proved under peer review in The End of Christianity cited in [1]. That treatment in SGG spans pp. 291-348 (Part V), with a pertinent semantic foundation spanning pp. 37-40 (Part II.2.2.3-6). My conclusion sums up the consequences of all that was there demonstrated: that my Goal Theory of Morality (a variant of Preference Utilitarianism) actually unifies all other ethical theories—it unites subjectivist and objectivist accounts of ethics (p. 346); it unites cognitivist and noncognitivist accounts of ethics under a common moral realism that explains how moral intuition is actually a manifestation of implicit cognitizable truth (pp. 346-47); it shows how egoism entails behavior that is observationally identical to altruism (pp. 347-48); and it “also unites both deontological and teleological ethics under the umbrella of a virtue-based theory” (p. 347). I illustrate all of this again in my subsequent paper in TEC (pp. 340-43), pointing out that “a theory that can unify all competing theories under one umbrella (and thereby explain and justify them all) has a strong claim to being true” (p. 424 n. 26).

[4] That Kant’s other formulations of the categorical imperative build on the first: His second formulation, “Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end,” is more like a second stage application of the first formulation. Kant believed that if we can will that a rule become universal, we would all will this rule to be universal: that people treat others as ends as well, and not only as a means. As such this formulation is too narrow and cryptic to have as much utility and clarity as the first formulation. It is also a disguised hypothetical (about what everyone would want; indeed, it is only a hypothesis about what he himself would want, because Kant could be wrong—if after seeing this in action, Kant could well decide he predicted its effects badly and would no longer will that it be a universal rule). Kant’s third formulation, “Every rational being must so act as if he were through his maxim always a legislating member in the universal kingdom of ends,” is just another way of describing the point of the first formulation, in particular that it has certain (universally desirable) ends as an objective, which is an even clearer (though still inadvertent) admission that even the first formulation is a hypothetical imperative after all.

[5] That Social Contract Theory reduces to Game Theory: Ken Binmore, Game Theory and the Social Contract (MIT Press: Vol. 1, 1994; Vol. 2, 1998). See also Gary Drescher, Good and Real: Demystifying Paradoxes from Physics to Ethics (MIT Press: 2006), pp. 273–320.