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Why Rule Utilitarianism Fails as a Moral Stance

By rule utilitarianism, here I will mean, roughly speaking, the moral stance summarized as follows:

  1. People experience varying degrees of wellbeing as a function of their circumstances; for example, peace and prosperity engender greater wellbeing than for their participants than war and famine.
  2. As a matter of fact, some value systems yield higher levels human wellbeing than others.
  3. Moral behavior consists in advocating and conforming to value systems that engender relatively high levels of human wellbeing.

Varieties of this position are advocated in academic philosophy, for example, by Richard Brandt, Brad Hooker, and R.M. Hare -- and in popular literature, for example, by Sam Harris in The Moral Landscape and (more cogently, in my opinion) by Stephen Pinker in the final chapter of his book Enlightenment Now. I do not believe that rule utilitarianism cuts much ice as a moral stance, and this essay will explain why I hold that opinion.

1. The problem of speciesism

In his book Enlightenment Now, psychologist Steven Pinker hedges on proposition #3 of the utilitarian platform, which I will call the axiom of humanism. Pinker writes, "Despite the word's root, humanism doesn't exclude the flourishing of animals" [p. 410]. Well, professor, it sho' 'nuff does exclude the flourishing of animals! If the ultimate moral purpose is to promote human flourishing, then the welfare non-human animals is excluded from consideration in the ultimate moral purpose. To be charitable, I suppose Pinker means that it is consistent with (3) that there is a legitimate secondary moral purpose in maximizing the wellbeing of animals. However, (a) I cannot be sure that he means that, and (b) it is unfortunate that he did not say what he meant, especially since this point is central to a weakness in the humanist position.

In The Moral Landscape, and in his TED talk on the same thesis, Sam Harris spends most of his time defending propositions (1) and (2) of the utilitarian position --- which is unfortunate, because I believe they are self-evident. To his credit, Harris does briefly address issue of "speciesism" (that is, assigning greater moral weight to the wellbeing of animals than humans), saying, "If we are more concerned about our fellow primates than we are about insects, as indeed we are, it's because we think they're exposed to a greater range of potential happiness and suffering." What Harris does not do is to place the range of animal experience on the scale with that of human experience to compare them, or give us any reason to think bottom of the scale for humans is meaningfully (if at all) above the top of the scale for other animals. Moreover, he gives no reason why we ought to draw a big red line at some arbitrary place on that scale, and write "Not OK to trap, shoot, eat, encage, or wear the skins of anything above this line." Perhaps that line reaches well down into the animal kingdom, and perhaps the line falls above the level of some of our fellow men. As a matter of ultimate concern, I cannot imagine an objective reason why it should not.

Perhaps Pinker and Harris don't spend much effort on the issue of speciesism because it is uncontroversial: of course human wellbeing has greater moral gravity than animal wellbeing, and the exact details of why and how much are not a pressing moral concern of our day. I submit, on the contrary, that accounting for speciesism is the one of the first jobs of any moral theory. I am not saying that perhaps we ought to start eating our dim-witted neighbors, or that we should all become vegans; I am saying that if you purport to found a moral theory on objective reason then you should actually do it, and that how that theory accounts for speciesism is an important test case for it.

To wit, either animals count as much as humans our moral calculus, or they do not. If animals count as much as humans, then most of us (non-vegetarians) are in a lot of trouble, or at least ought to be. On the other hand, if animals don't count as much as humans, then the reason they don't, carried to its logical conclusion, is liable to be the reason that some humans don't count as much as others. Abraham Lincoln famously made a similar argument over the morality of slavery:

You say A is white, and B is black. It is color, then; the lighter, having the right to enslave the darker? Take care. By this rule, you are to be a slave to the first man you meet, with a fairer skin than your own. You do not mean color exactly? — You mean whites are intellectually the superiors to blacks, and therefore have the right to enslave them? Take care again. By this rule, you are to be slave to the first man you meet, with an intellect superior to your own. But say you, it is a question of interest; and, if you can make it your interest, you have the right to enslave another. Very well. And if he can make it his interest, he has the right to enslave you. [From Lincoln's collected notes; date uncertain]

In the spirit of Lincoln's argument, for example, do non-humans count less, as Harris claims, because they allegedly have less varied and vivid emotional experience? It is not clear to me that they do in the first place, or, if they do, that they do by a degree sufficient to make cannibalism forbidden and vegetarianism optional. Do non-humans count less because they are less intelligent? In that case, the utilitarian is obliged to explain why the line is drawn just where it is, and, indeed, why, in the best of all possible worlds, deep fried dumbass shouldn't be an item on the menu at Arby's.

The fact that Pinker and Harris do not resolve the issue of speciesism is important -- not because their conclusions on the matter are or ought to be controversial, but because it is the first sign that they are not deriving a theory from first principles, but instead rationalizing the shared common sense of their own culture.

2. And who is my neighbor?

John Lennon famously sang, "All you need is love". Perhaps love is all you need, but, as Bo Diddley famously sang, the hard question remains: Who do you love?

Suppose we were to grant (which I do not) that it is objectively evident that the wellbeing of humans is categorically more valuable than that of other animals. The fact remains the wellbeing of some humans might count more than that of others, from my perspective, as an ultimate moral concern. Indeed, some humans might not count at all except as targets and trophies -- and many cultures have taken this view unashamedly. For example, the opening stanza of the Anglo Saxon poem Beowulf extolls the virtues of the Danish king Sheild Sheafson for the laudable accomplishment of subjugating not just some but all of the neighboring tribes, and for driving them in terror -- not from their fortresses, not from their castles, but from their bar stools:

So. The Spear-Danes in days gone by
And the kings who ruled them had courage and greatness.
We have heard of those princes’ heroic campaigns.
There was Shield Sheafson, scourge of many tribes,
A wrecker of mead-benches, rampaging among foes.
This terror of the hall-troops had come far.
A foundling to start with, he would flourish later on
As his powers waxed and his worth was proved.
In the end each clan on the outlying coasts
Beyond the whale-road had to yield to him
And begin to pay tribute. That was one good king.
[translation by Seamus Heaney, emphasis added]

The literature, monuments, and oral traditions of the world are replete with examples of this sentiment, but for the sake of space I will give just one more example. The inscription on a monument to honor the Roman general Pompey in honor of his 45'th birthday reads,

Pompey, the people’s general, has in three years captured fifteen hundred cities, and slain, taken, or reduced to submission twelve million human beings.

In the West today, people tear down monuments claiming that the men they honor were enslavers or imperialists -- but evidently other cultures put up monuments to glorify their leaders for those very characteristics. So it is not a no-brainer -- that is to say, not at all self-evident -- that the welfare of members of foreign tribes ought to play any role in our moral calculations at all -- or indeed that the subjugation and exploitation of foreign tribes is not a positive moral good from our own perspective. That is how the Romans and the Saxons saw it. If you or I had been born into those cultures we would probably would have felt the same way -- and so, I dare say, would Sam Harris and Steven Pinker.

I imagine the utilitarian response would that we are all better off if we take the modern Western view (of course) that exploiting foreigners is inherently immoral. Sam Harris asks us to imagine two people who are forced to choose between (a) cooperating to build a better society, or (b) smashing each other in the face with rocks. If those are the options, I would certainly choose (a) -- but those are not the options. Harris left out the salient option (c): I smash you in the face with a rock and take your wallet. This is not a straw man, and it has been the position of many honest, intelligent, and upright people. If one suggested to Alexander the Great -- a student of Aristotle -- that "we all" are better off if "we all" lay down our weapons, he might ask, "who is we all??" He might say that he cares little for what makes barbarians (that is, non-Greeks) better off, any more than he cares what makes apes or pigs better off -- and that your way of drawing the circle of love, so as to include all humans but exclude apes and pigs, is no better than his. I imagine the utilitarian response to that would be, "You fiend!", and that the Greek response to that would be "Get out of my sight, you womanish punk". So, from a logical perspective, who won the debate? Nobody did.

Pinker almost concedes this, writing "If there were a callous, egoistic, megalomaniacal sociopath who could exploit everyone else with impunity, no argument could convince him he had omitted a logical fallacy" [Enlightenment Now, p. 412] -- but it is not clear whether he means that the sociopath could not be convinced because he has a thick skull, or whether he is actually not committing a logical fallacy. I emailed Dr. Pinker for a clarification, and he was kind enough to reply, acknowledging that the megalomaniacal sociopath is actually not committing a logical fallacy. Note that (1) this is a second example of Pinker's writing being vague exactly where the argument is weakest (the first being the issue of speciesism), and (2) a Roman general is not a megalomaniacal sociopath or anything of the sort, and whatever we claim to be objectively self-evident ought to be evident to him as well as us.

In fact, Pinker considers something like the argument with a Roman general in his book. His imagined response (in his version to Nietzsche, a Romanophile, rather than an actual Roman) is as follows:

I [Steven Pinker] am a superman, hard, cold, terrible, without feelings and without conscience. As you recommend, I will achieve glory by exterminating some chattering dwarves. Starting with you, shortly. And I might do a few things to that Nazi sister of yours, too. Unless you can think of a reason why I should not [Enlightenment Now, p. 446].

But now that Professor Pinker himself has switched gears, from the strictly logical to the ad baculum, I submit that he is obviously bluffing, and the Romans were not bluffing at all. Someone would win that debate -- and that the Roman argument might have something to do with a crucifix.

In any case, an allegedly universal and self-evident regard for "human wellbeing" leaves unanswered the central question of morality: in the words of the great moral philosopher Bo Diddley, Who do you love? Speciesism is only the thin end of the wedge: not only do I generally value the wellbeing of people more than that that of cows and rabbits, I also value the wellbeing of my people more than I value that of other people -- and, in my view, rightly so. Thus, premises (1) and (2) of the humanist/utilitarian position do not imply conclusion (3) because, as an ultimate concern, I value the wellbeing of people in my identity group over that of people outside my identity group, and it is only right that I should do this. Thus, maximizing human wellbeing -- in the sense where all humans count equally -- is not something I am actually interested in. Moreover, I do not feel it is something I ought to be particularly interested in.

Now in response to this, you might say that I am a scoundrel and a villain. In response to that, I say that's just, like, your opinion, man. Philosophers such as Peter Singer, and popular writers like Stephen Pinker, insist that I must be impartial between the wellbeing of my people on the one hand, and that of homo sapiens at large on the other. For example, Pinker writes, "There is nothing magic about the pronouns I and me that would justify privileging my interests over yours or anyone else's" [Enlightenment Now, p. 412]. To that I reply, why on Earth would I need magic, or even justification, to privilege my own interests over yours as matter of ultimate concern? Of course I privilege my interests over yours, and almost certainly vice versa. In fact, unless you are a friend of mine, not only do I privilege my own interests over yours, I privilege my dog's interests over yours. For example, if my dog needed a life-saving medical procedure that costs $5000, I would pay for it, but if you need a life-saving medical procedure that cost $5000, I probably would not pay for it -- and if an orphan from East Bengal needed a life-saving medical procedure that costs $5000 (which one probably does at this very moment), I would almost certainly not pay for it, and neither would you (unless you are actually paying for it).

I must not be alone in caring more about my dog than I do about a random stranger. The average lifetime cost of responsibly owning a dog in the United States is around $29,000 -- while, according to the Givewell organization, the cost of saving the life of one unfortunate fellow man at large by donating to a well chosen charity is around $4500 [source]. If those figures are correct, it means that if you own a dog, then you could have allocated the cost of owning that dog to save the lives of about six people on average (and if the figures are wrong, something like that is true anyway). Now, Steven Pinker himself once tweeted that dog ownership comes with empirically verifiable psychological benefits for the dog owner. In his excitement over those psychological benefits, I suppose, he neglected to mention that it also comes with the opportunity cost of six (or so) third world children dying in squalid privation. If Pinker really believes, as he claims to believe, that "reducing the suffering and enhance the flourishing of human beings is the ultimate moral purpose," he sure isn't selling it very hard. But then again, no one in their right mind is.

Not only do I actually value my dog's wellbeing above that or a random human stranger, I submit it is only right that I should. That is to say, it would be immoral of me not to privilege my dog's wellbeing over that of a human stranger. Indeed, if a man let his family dog pass away, when he could have saved the dog's life for a few thousand dollars, and he spent that money instead to save the life of a foreigner whom he had never met, then, all else being equal, I would prefer not to have him as a countryman, let alone a friend.

In one talk, Pinker has said, "You cannot expect me to take you seriously if you are espousing moral rules that privilege your interests above mine." But, professor, if I have more and better men on my side, it does not matter whether you take me seriously; it only matters whether they do. Again, I am not saying that it would be right to take advantage of that situation of having more and better men on my side; I am saying that the Pinker and Harris's egg headed argument yields no objective reason why I shouldn't.

3. Degrees of neighborship

One of Sam Harris's favorite examples to illustrate the objectiveness of values is "the worst possible misery for everyone", which he claims is self-evidently and objectively bad situation. I think this is an egregious misdirection, because moral questions are not about the choice between win-win and lose-lose. If iron axes work better than bronze axes, for everyone, at every level, all things considered, then by all means let us use iron -- but that is not a moral decision. I have a moral decision to make when, for example, (1) I have the opportunity to gain at your expense, all things considered, and (2) I don't care about your wellbeing as much as I care about mine.

But not all moral tradeoffs are one-on-one. Human nature being what it is, groups at all levels split into factions which then try to have their way with each other -- from nuclear families, to PTA boards, to political parties, to nations, to the whole of humanity. A code of conduct that is good for my community at one level might subtract from the good of a smaller, tighter community of which I am also a member -- so, real which of those codes should (should, in the moral sense) I advocate and adhere to?

As a matter of fact, the wellbeing of different groups, of which I am a member, often trade against each other in moral decisions -- and the purpose of moral precepts, largely if not mainly, is to manage tradeoffs between our concerns for the welfare of different groups, with different degrees of shared identity, of which we are a common member. What looks like the same group from afar, or in one conflict, may look like different ethnicities or religions when you zoom in, or look at a different conflict. This is nothing new. For example, the Book of Joshua, written at the latest around 600 BC, records nations being formally subdivided into hierarchies of tribes, clans, and families:

So Joshua got up early in the morning and brought Israel forward by tribes, and the tribe of Judah was selected. So he brought the family of Judah forward, and he selected the family of the Zerahites; then he brought the family of the Zerahites forward man by man, and Zabdi was selected. And he brought his household forward man by man; and Achan, son of Carmi, son of Zabdi, son of Zerah, from the tribe of Judah, was selected.

And these various hierarchies were well known to endure conflicts of interest, if not outright enmity, at every level of the hierarchy, from civil war between tribes (and coalitions of tribes) within a nation, right down to nuclear families:

Then the men of Judah gave a shout: and as the men of Judah [Southern Israel] shouted, it came to pass, that God smote Jeroboam and all [Northern] Israel before Abijah and Judah. [2 Chronicles: 15]
And Cain talked with Abel his brother: and it came to pass, when they were in the field, that Cain rose up against Abel his brother, and slew him. [Genesis 4:8]

So what your "ingroup" looks like depend on the particular conflict we are looking at, and the level of structure at which the conflict takes place. These conflicts can be life and death at all levels, and someone who is in your ingroup during a conflict at one level may be in the outgroup in a conflict at another level on another occasion. This phenomenon is a major theme -- arguably the major theme -- of the oldest written documents that exist on every continent where writing was discovered. Thus is a mistake in moral reasoning to conceptualize a code of conduct that benefits "the community": each person is, after all, a member of multiple overlapping communities of various sizes and levels of cohesion, whose interests are frequently in conflict with each other.

Now hear this: when we are looking for a win-win solution that benefits everyone at all levels without hurting anyone at any level of "our community", this is an engineering problem, or a social engineering problem, but not an ethical problem. It is the win-lose scenarios, which trade the wellbeing of one level of my community against that of another, that fall into the domain of ethics. Of course we are more concerned for the welfare of those whose identities have more in common with our own -- but how steep should the drop-off be as a function of shared identity? Should it converge to zero for humanity at large? Less than zero for our enemies? How about rabbits and cows? As an ultimate concern, who do you love, and exactly how much, when it comes to decisions that trade between the wellbeing of one level of your community and another (self, family, clan, tribe, nation, humanity, vertebrates at large)? That is a central problem, if not the central problem, of ethical discourse -- and it is a question about which utilitarianism has nothing to say, and about which humanism begs the question from the outset.

4. No Moral Verve

At the end of the day, the conversation on ethics should come to something more than chalk on a board. When the chalk dust settles, if we have done a decent job of it, we should bring away something that can inspire us to rise to the call of duty when duty gets tough. The fatal defect of humanism in this regard is that practically no one -- neither you, nor I, nor Steven Pinker, nor Sam Harris, nor John Stuart Mill himself -- actually gives a leaping rat's ass about the suffering or the flourishing of homo sapiens at large. Such was eloquently voiced by Adam Smith, and his statement is worth quoting at length:

Let us suppose that the great empire of China, with all its myriads of inhabitants, was suddenly swallowed up by an earthquake, and let us consider how a man of humanity in Europe, who had no sort of connection with that part of the world, would be affected upon receiving intelligence of this dreadful calamity. He would, I imagine, first of all, express very strongly his sorrow for the misfortune of that unhappy people, he would make many melancholy reflections upon the precariousness of human life, and the vanity of all the labours of man, which could thus be annihilated in a moment. He would too, perhaps, if he was a man of speculation, enter into many reasonings concerning the effects which this disaster might produce upon the commerce of Europe, and the trade and business of the world in general. And when all this fine philosophy was over, when all these humane sentiments had been once fairly expressed, he would pursue his business or his pleasure, take his repose or his diversion, with the same ease and tranquility, as if no such accident had happened. [Smith (1759): The Theory of Moral Sentiments]

Here is the point. As C.S. Lewis wrote, In battle it is not syllogisms [logic] that will keep the reluctant nerves and muscles to their post in the third hour of the bombardment ["The Abolition of Man"]. Lewis was right about this -- and, while we are making a list of things that do not inspire people to rise to call of duty when duty gets tough, we can include on that list any concern they might claim to have for the welfare of human beings at large.

5. Mumbo-Jumbo

Be careful what you do,
Or Mumbo-Jumbo, God of the Congo,
And all of the other
Gods of the Congo,
Mumbo-Jumbo will hoo-doo you,
Mumbo-Jumbo will hoo-doo you,
Mumbo-Jumbo will hoo-doo you.*
[ Vachel Lindsay: The Congo]

In a discussion with Alex O'Connor, Sam Harris invites us to imagine two people on an Island, who can choose either to cooperate and build a beautiful life together, or to start smashing each other in the face with rocks. It is immoral to smash someone in the face with a rock, he infers, because if we all started smashing each other in the face with rocks, we would all be miserable. Indeed, I agree that if I had a choice between everyone smashing everyone in the face with a rock, and nobody smashing anyone in the face with a rock, I would certainly choose nobody smashing anyone. But in reality, I do not get to choose whether everybody smashes everyone in the face with a rock. The decision I get to actually make, in which my ethics actually plays a role, is whether I smash you in the face with a rock, and take your wallet in the bargain, which, say, has $5,000 in it. With that, it is suddenly not so clear why that wouldn't maximize the satisfaction of my ultimate concerns -- especially if I value $5,000 more than I value your life (which again, unless you are a friend of mine, I unashamedly do).

On top of ignoring the multilayered, competitive nature of the human condition, and on top of having no practical motivational force even for its professed adherents, another problem with rule utilitarianism is the voodoo it invokes to connect (a) performing a particular action with (b) what would happen, counterfactually, if everyone followed the salient rule that permits the action. For a simple example, let us imagine that I steal a tootsie roll from a convenience store. In this scenario, let us imagine that I am poor and the convenience store owner is rich, and that tootsie roll does me more good than it would have done the store owner if it had remained in his store. In the world of mystical utilitarian counterfactuals, if everyone stole everything all the time, then everyone would clearly be worse off -- but in the actual world, me stealing a bite of candy is not going to cause everyone to steal everything all the time, or, probably, cause anyone else to steal anything else ever. Even if an individual tootsie roll pilferage did have some miniscule ripple effect on society, I would still expect the material impact on me personally to be less than the cost of the candy I stole. To put it more generally, when someone steals something and gets away with it, they do not reasonably expect to lose net income as a result. So, why on Earth should I care about what would happen in the sci-fi scenario where everyone stole everything all the time? I cannot imagine an objective reason why I should.

Perhaps there is some deep metaphysical argument that establishes, on an objective basis, that one ought to behave in the way they wish others in "their community" to behave (if, again counterfactually, there were such a thing as "their community") -- or perhaps there is some kind of cosmic karma stipulating that what goes around invariably comes around on this Earth, but (1) I cannot imagine what that metaphysical argument would be, (2) the world doesn't look to me like it works that way, and (3) neither Pinker, nor Harriss, nor Singer, nor Benthem, nor Mill actually give such metaphysical arguments, nor attempt to show that the world does work that way.

Let me repeat once again that I am not advocating nihilism here. What I am saying is this: if utilitarians claim to base their moral theory on objective reason -- indeed, if they claim to do anything other than manufacture a flimsy rationalization for the moral common sense of their own culture -- then it is precisely the Devil's advocate that must contend with, and it seems to me they are in a hopeless position to do so.

Conclusion

When I say that utilitarianism has nothing useful to say about real world ethical problems, I mean it. Of course one might give evidence about the impacts of some rule or policy, which might then inform whether we want to adopt that rule or policy -- but I doubt the following words have ever been uttered in a real debate over policy or ethics: I conceded that your policy/rule/value-premise, if adopted, would benefit every level of our community more than mine does, but to Hell with that. The fact is that everyone prefers policies that benefit their communities when they are a win/win at every level -- whether or not they have read one fancy word of John Stuart Mill, Jeremy Bentham, Peter Singer, Sam Harris, or Steven Pinker. Thus, to the degree that utilitarianism has any force in the real world, it adds nothing to the conversation that wasn't already inherent in common sense. On the other hand, to the degree that utilitarianism is not redundant with common sense, it has no motivational force, even for its professed adherents -- especially if they own a dog.

I submit that the position of utilitarianism is not only weak, but so evidently preposterous that its firm embrace requires an act of intellectual dishonesty. I can say this without contempt, because less than ten years ago I myself espoused utilitarianism. I knew then and I know now that I was not being intellectually honest in espousing this view. To my credit, I could not bring myself to write a defense of utilitarianism, even though I tried -- because I could not come up with an argument for it that I found convincing. Yet, I presumed that I would eventually be able to produce such an argument, and I did state utilitarianism as my position, without confessing that I could not defend the position to my own satisfaction.

I further submit that programs like utilitarianism are not only mistaken but harmful. They are not just a little bit harmful, but disastrously harmful, and we can see the engendered disaster unfolding before our eyes. The problem is not that utilitarians are necessarily bad people; it is that, if they are good people, they are good people in some sense by accident: reflexively mimicking the virtues and values of their inherited traditions, while at the same time denigrating tradition, and mistaking their moral heritage for something they have discovered independently. As John Selden wrote,

Custom quite often wears the mask of nature, and we are taken in [by this] to the point that the practices adopted by nations, based solely on custom, frequently come to seem like natural and universal laws of mankind. [Natural and National Law, Book 1, Chapter 6]

The problem with subverting the actual source of our moral norms and replacing it with a feeble rationalization is this: each generation naturally (and rightly) pushes back against their inherited traditions, and pokes to see what is underneath them. If the actual source of those traditions has been forgotten, and they are presented instead as being founded on hollow arguments, the pushback will blow the house down. Sons will live out the virtues of their fathers less with each passing generation, progressively supplanting those virtues with the unrestrained will of their own flesh. That is what we are seeing in our culture today -- and impotent, ivory tower theories of morality are part of the problem.

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Your argument would be more sound if you didn't misrepresent one of the most famous lines in the English language.

The line is "We hold these truths to be self evident, that all men are created equal," etc. What Jefferson is doing here is declaring his axioms. He does make several arguments later in the Declaration, but they follow from those axioms; they aren't meant to prove them. Jefferson is speaking to multiple audiences, some of whom reject his axioms--the Declaration is a bold statement that the American colonies intend to chart a path entirely separated from the monarchical institutions of Europe, from the bedrock assumptions of society up.

You can't rephrase "we hold these truths to be self evident" as "obviously." Your conclusion, that handing down traditions takes effort, is sound, but Jefferson would likely agree. Ben Franklin certainly would; when asked what kind of government the Constitution created, he responded, "A republic, if you can keep it." The conditional displays your point, that traditions and institutions require maintenance, and are not immune to decay if neglected.

You can't rephrase "we hold these truths to be self evident" as "obviously."

Isn't that exactly what "self-evident" means?

self-ev·i·dent
/ˌselfˈevəd(ə)nt/
adjective
not needing to be demonstrated or explained; obvious.
[Oxford Dictionary of the English Language]

Also,

What Jefferson is doing here is declaring his axioms. He does make several arguments later in the Declaration, but they follow from those axioms; they aren't meant to prove them.

I don't dispute this; there is no need to prove something if it is self-evident, in the dictionary sense of being obvious.

Your conclusion, that handing down traditions takes effort, is sound, but Jefferson would likely agree.

I believe not only that it takes effort, but also that it a moral duty of each generation. I am curious why you think Jefferson would agree. For example, coincidentally, here is another use of the phrase "self-evident" by Jefferson:

The question Whether one generation of men has a right to bind another, seems never to have been started either on this or our side of the water. Yet it is a question of such consequences as not only to merit decision, but place also, among the fundamental principles of every government. The course of reflection in which we are immersed here on the elementary principles of society has presented this question to my mind; & that no such obligation can be so transmitted I think very capable of proof. I set out on this ground, which I suppose to be self-evident, ‘that the earth belongs in usufruct to the living’: that the dead have neither powers nor rights over it. The portion occupied by any individual ceases to be his when himself ceases to be, & reverts to the society...We seem not to have percieved that, by the law of nature, one generation is to another as one independant nation to another.. [Letter to James Madison, (6 September 1789), emphasis added]

Jefferson seems to hold that a given generation has no obligation to carry on the traditions of its forebears, even from a single generation ago -- and, in the same letter to Madison of September 1789, he argues that, therefore, the national constitution should be rewritten every twenty years:

The constitution and the laws of their predecessors extinguished then in their natural course with those who gave them being. This could preserve that being till it ceased to be itself, and no longer. Every constitution then, and every law, naturally expires at the end of 19 years.

He says in the same paragraph that the constitution should not merely be amended, but rewritten from scratch in each generation (that is, every 20 years). So much for sacred tradition.

An axiom is a premise to an argument. You don't set out to prove axioms within the scope of an argument not because they are obviously true, but because they are outside the scope of the argument by definition. You use axioms to prove conclusions. Yes, you may use "self-evident" more or less interchangeably with "obvious," but I never said otherwise. I said that "we hold these truths to be self-evident" is not the same as "self-evidently." "We hold" is doing crucial work here, and may not be discarded without changing the meaning of the statement.

Jefferson's use of "self-evident" in the quoted letter to Madison is consistent with the above. Again, Jefferson is declaring an axiom, or at least offering one for discussion--"I suppose to be" is a somewhat less emphatic phrasing than "we hold," but it serves the same basic purpose.

Jefferson's twenty-year sunset idea is famously nutty[1], but there's a distinction to be drawn between his private writings to Madison, and the public documents he drafted, like the Declaration. In the Declaration, Jefferson isn't just speaking for himself--after all, there's a long list of signatories, and Jefferson's early drafts got cut down a fair bit in editing-by-committee.

[1] Well, they are famously nutty now, with the posthumous publication of a great many letters and documents that were private at the time they were written. As I recall, Madison's response was more or less, "what a fascinating idea; you should definitely not mention it to anyone else." Madison was considerably more sensible than Jefferson, admittedly not the highest of bars.

As you are likely aware, Jefferson was strongly influenced by John Locke in the writing of the Declaration. Locke wrote that the doctrine of equal natural negative rights was plainly discernable by independent reason:

The state of Nature has a law of Nature to govern it, which obliges every one, and reason, which is that law, teaches all mankind who will but consult it, that being all equal and independent, no one ought to harm another in his life, health, liberty or possessions; [Locke, Two Treatises of Government, essay II, section II].

In the opening words of the Declaration, Jefferson follows Locke's wording in this passage fairly closely, writing "life, liberty, and the pursuit of happiness", where Locke had written "life, health, liberty or possessions." In the same paragraph, Locke says, not that these precepts are part of English or Christian traditions, but that they can be ascertained by "all mankind who will but consult it [reason]". So the idea that these notions would be obvious is not a new idea in Jefferson's time, nor a straw man, but the stated opinion of the thinker who was probably most influential on Jefferson's writing. Logical inference from self-evident premises, in the style of Euclid, was in fashion during that period in writing on subjects from physics to politics -- however queer a fashion it now appears to us.

The fact that Jefferson was advised by Madison to keep his opinions to himself does not make them any less his opinions, and the fact that he was writing a public document does keep his opinion from working its way into the text. The text says what the text says.

An axiom is a premise to an argument. You don't set out to prove axioms within the scope of an argument not because they are obviously true, but because they are outside the scope of the argument by definition.

The phrase "self-evident" has meant the same thing from the time of Aquinas, through the time of Jefferson, up until now:

self-ev·i·dent\ /ˌselfˈevəd(ə)nt/
adjective
not needing to be demonstrated or explained; obvious.
[Oxford Dictionary of the English Language]

Can you explain more carefully, from a textual perspective, why you think it means something else in the Declaration? If this is your whole argument,

I said that "we hold these truths to be self-evident" is not the same as "self-evidently".

I don't buy it.