Interrogating the Symmetry Thesis
Happiness and suffering are worlds apart. Many philosophers, however, account for this qualitative difference in the simplest way possible: they flip the sign. Happiness and suffering, or pleasure and pain, become “positive” and “negative” welfare or utility, respectively, differing in direction but not in kind. They treat them as mirror images of each other, demanding symmetric treatment: increase one, reduce the other.
The result is a simple, if elegant framework, promising tractability in decision-making. Yet we should pause before running with it.
The Symmetry Thesis
It is one thing to hold that happiness and suffering, or pleasure and pain, are positive and negative elements of welfare or utility. It is yet another to hold that they are mirror images of one another, distinguished only by their sign. That is a further claim. We might call this claim the symmetry thesis.
Perhaps this seems like the “default” view of things to some people, but why is that? It might sometimes make matters simpler to treat happiness and suffering symmetrically, but that cannot by itself be a sufficient reason to do so. Really, it is not an innocent starting assumption but a substantive claim requiring defense. Indeed, there is a long tradition of philosophers arguing for asymmetries between happiness and suffering, as discussed in chapter 1 of this book.
The Classical Utilitarians
The classical utilitarians are the primary source of the symmetry thesis. Bentham, Mill, and Sidgwick thought that the amount of pleasure and pain in the world could in theory be aggregated, with the result guiding our actions. In particular, the aim was to produce the greatest “surplus of pleasure over pain,” as Sidgwick put it. Their framework presupposed that pleasure and pain are fundamentally the same kind of thing, differing only in sign, so that in principle the calculations would be relatively straightforward.
Unfortunately, the classical utilitarians did not so much defend the symmetry thesis as assume it.
Jeremy Bentham held that pain and pleasure were our two “sovereign masters” and contended that it was “for them alone to point out what we ought to do.” From this it does not follow that pleasure and pain should have equal authority in guiding our action, such that we should be indifferent between the aims of increasing pleasure and decreasing pain.
But Bentham’s “felicific calculus” brooks no such complications. According to Bentham, we may simply “sum up all the values of all the pleasures on the one side, and those of all the pains on the other,” and let the resulting balance determine whether an act is right. In principle, this is pretty straightforward, except that we must pay attention to multiple dimensions of experience, from the intensity of a sensation to its “fecundity.” Yet for all this attention to detail here, Bentham does not appear to consider whether there might be a fundamental difference between our alleged “two masters” that has its own normative significance.
J. S. Mill carried this view forward. His principal innovation was to distinguish kinds of pleasure, arguing that some pleasures are “higher” and more valuable than others. But Mill did not suppose an analogous qualitative distinction held between pleasure and pain. Instead, he treated happiness and unhappiness as mirror images: happiness was “pleasure, and the absence of pain,” and unhappiness “pain, and the privation of pleasure.”
Sidgwick mostly agreed, though he opened the door to questioning the symmetry thesis. Sidgwick was more candid than Bentham and Mill about the difficulty of aggregating pleasure and pain. He admitted that he could “only to a very limited extent… obtain clear and definite results” from introspective comparisons of experiences. And he suggested that even more difficult than comparing pleasures with one another was comparing pleasure with pain—and to decide “how much of the one kind of feeling we consider to be exactly balanced by a given amount of the other.”
In this latter point, he suggests that individual units of pleasure and pain do not have the same normative significance, pound for pound. He continued, however, to affirm a more basic symmetry between happiness and suffering, regarding them in general as opposites. Indeed, he described pain as the “negative quantity of pleasure” and agreed with his predecessors that enough pleasure or pain can outweigh—as he put it, “annihilate”—the other.
Deeper Investigation
It is striking how little reflection Bentham, Mill, and Sidgwick did to justify their assumption of symmetry between happiness and suffering. As mentioned, Mill reflected at length on pleasure and argued for qualitative distinctions within it, yet he made no such distinction between pleasure and pain. This is curious, since there appears to be an even deeper qualitative divide between pleasure and pain. Indeed, we already distinguish them conceptually; Mill, however, drew no normative conclusions from this—only from his own distinction between types of pleasure.
On reflection, it may seem that happy experiences lack anything that would make them genuine opposites of suffering. (What about happiness is anti-suffering exactly?) Rather than opposites, happiness and suffering may be morally orthogonal: genuinely different kinds of experience, perhaps both elements of welfare, but not to be treated symmetrically.
Some of our moral judgments may also be hard to reconcile with the symmetry thesis. Many seem to treat the prevention or alleviation of severe suffering as more urgent than increasing happiness. In Mayerfeld’s anesthesia case, where we can choose between preventing excruciating agony and enhancing the pleasure of already-happy people, it may seem compelling to do the former.
Perhaps you also endorse the procreation asymmetry, which holds that we have a strong reason or duty not to bring a miserable child into existence but no reason (or a weaker one) to bring a happy child into existence. These judgments may be difficult to explain if we take happiness and suffering to be mirror images.
Finally, perhaps you agree that the Very Repugnant Conclusion is aptly named. If happiness and suffering were mirror images of each other, it seems that the extreme suffering of many could be outweighed by the mild happiness of an enormous number of beings. Yet that may seem implausible—even more so than the infamous Repugnant Conclusion.
Reflect on Your Intuitions
If not symmetrically, how should we treat happiness and suffering? Several possibilities are available. One might hold that they differ in moral weight by some finite ratio; that one matters lexically more than the other, such that no amount of one can outweigh some amount of the other; or that one adds no independent value at all, but instead marks the mere absence of the other.
The point is not that any one of these views is correct. Rather, it is that we should allow careful reflection and considered intuitions to guide our theorizing, instead of assuming from the outset that pleasure and pain belong on a single, symmetrical ledger. Most people encounter classical utilitarianism before explicitly considering whether happiness and suffering deserve to be treated symmetrically. Because Bentham, Mill, and Sidgwick did not pause much to defend their assumption, we may inherit it without noticing, allowing it to harden into a cached thought that quietly structures our moral reasoning.
Many philosophers have suspected that suffering carries a moral importance that resists easy comparison—and aggregation—with positive goods like happiness. Whether or not one ultimately agrees, we should follow these philosophers in scrutinizing the symmetry thesis. This commits us to no particular theory about the relative value of happiness and suffering—only to rejecting the idea that the classical utilitarian picture is the default. If pleasure and pain are to be treated symmetrically, that conclusion must be argued for, not simply assumed.