Myers implicitly describes the utilitarianism as "maximizing well-being". Alternatively, utilitarianism is often described as the theory that an individual ought to do what will result in the greatest good for the greatest number. After taking a brief detour to criticize a vague conception of "relativism", Myers focuses her critique of utilitarianism on the calculation problem. While her critique addresses a specific theory of utilitarianism, it fails to adequately rebut the specific theory. More importantly, it fails to even address the fundamental concept of utilitarianism as a paradigm.
The calculation problem might undermine utilitarianism, but Myers fails to prove it. Myers succinctly describes the calculation problem: If we really are going to act to maximize well-being, we need to calculate not just the direct effects of our actions, but all the indirect effects: the effects of the effects, the effects of the effects of the effects, and so on ad infinitum. But noting that the full effect of an action is infinite is not to say it cannot be calculated. We have many conceptual tools to think about and estimate infinite calculations. In the same sense, quantum mechanics depends (or seems to depend) on not only the quantum state of every particle in the universe, but on the quantum state of all possible virtual particles that might have been created in every possible alternative history. But because these effects quickly become vanishingly small, we can get very accurate estimates of measurable quantities by considering only a finite (and small) number of possible interactions. Similarly, the indirect effects might well be infinite, but if they were to quickly become small, we might only need to use tractable calculations to get a good enough estimate of the effect of an action on social well-being.
Alternatively, we can deal with infinite calculations by using probability theory. I do not need to calculate an infinite (or intractably large or impossibly precise) number of interactions between a coin, my thumb, a lot of air molecules and the table to know that it has a 50% chance of landing heads. We do not have to perform a lot of quantum mechanical calculations to know the half-life of a radioactive isotope. Similarly, if we could empirically determine that the probability of good effects was very high for, to use Myers' example, dedicating a medical professional to curing malaria, we would be justified under even a simple utilitarian theory in doing so, even if we did not know that in this specific case one of the indirect effects would actually be highly negative.
Infinite calculation might undermine utilitarianism, but only if it could be shown that the effects of this infinite calculation typically* were radically divergent, nonlinear and chaotic. In this case, we could not depend on the later effects dampening out as we got "farther away" from the proximate effects of an action, nor could we adequately calculate probabilities. While it might be possible that the effects of human actions really are radically nonlinear (witness any number of science fiction time-travel stories about the dire consequences of making even the tiniest changes to the past), this view doesn't really conform to our everyday experience. Whether or not utilitarianism is an adequate moral theory, human beings typically do act in a loose sense to "maximize well-being". We don't particularly worry — and don't seem to need to worry — that if we hold the door open for a stranger in Peoria that the "butterfly effect" will cause the death of a child in Bogotá. History has shown that when we do so as individuals, people in general really are better off. We might, of course, be mistaken, but to adequately rebut utilitarianism, Myers would need to demonstrate nonlinearity, not just infinity.
*To be sure, there are "edge cases" where the nonlinear effects of human actions become obvious and important. But if such situations really were unusually, we could simply treat utilitarianism as a partial theory, in much the same sense that we treat Newtonian gravitation as a partial theory, inapplicable only in unusual cases, such as near a black hole or neutron star (and General Relativity as a better partial theory, inapplicable only at the singularity inside a black hole.
Myers can be forgiven for "disliking utilitarianism." If you read Bentham, utilitarianism is presented as the very simplistic view that an individual's well-being can be represented as a simple scalar value, and we can calculate overall well-being by simply summing up these scalar values over all the individuals in a society. This specific theory so obviously contradicts our moral intuition that we must view it with the most extreme suspicion. Bentham did have an ulterior motive: as Michael Perelman argues out in The Invention of Capitalism, Bentham was concerned with creating a philosophical justification for the exploitation of the working class for the "benefit of society*". Indeed we can quickly dismiss Bentham's over-simplistic theory with David Chalmers' tongue-in-cheek definition of "Benthamite" as "someone who really would ignore their own drowning child in order to push ... [a button] which will cause mild sexual gratification in a warehouse full of rabbits."
But to dismiss a particular theory of utilitarianism is not to dismiss the underlying concept. In Utilitarianism, John Stuart Mill presents the underlying concept as
The creed which accepts as the foundation of morals, Utility, or the Greatest Happiness Principle, holds that actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure, and the absence of pain; by unhappiness, pain, and the privation of pleasure.Notice the vagueness of Mill's definition. Mill does not tell us here how to actually calculate the rightness of an action; he asserts only that rightness is somehow substantively and necessarily connected to human happiness and pleasure. (Mill later tries to objectively quantify happiness and suffering, but we again get to a specific theory, which might be wrong even even if the key principle were correct.)
Mill's definition here might be vague, but it is not vacuous or tautological. It has at least enough definite meaning to serve as a starting point, because we can differentiate utilitarianism from deonticism. In deonticism, an action is right or wrong without regard to its effects on human happiness or suffering. Ignoring the case where deonticism and utilitarianism are trivially equivalent*, to assert deonticism entails asserting that there could be right actions that could, even if we knew everything, entail the maximum suffering and least happiness of all human beings. Scientific laws have this deontic flavor: if the laws of the universe entailed that all human beings were to die tomorrow in horrible pain (perhaps from a massive gamma ray burst from a nearby supernova), the consequences of the laws of physics would be irrelevant to their truth. While it might be difficult to construct a satisfying utilitarian theory, abandoning utilitarianism at a fundamental level for deonticism creates its own difficulties.
*I.e. actions are be right or wrong without regard to their consequences, but it in all cases the deontically right action "just so happens" to produce the best consequences.
The biggest problem with deonticism is epistemological: How can we know which actions are intrinsically correct, without appealing to whatever evidence we can gather about the consequences of those actions? I'm not talking about how we can know in exact detail or with absolute certainty; I'm talking about how we can get this sort of knowledge off the ground and at least get a sense. We cannot appeal to the scientific method. In science, we conclude that some statement constitutes a law of physics if and only if we never observe a true exception to the statement. We know that things always fall towards the ground when we drop them* just because we never observe things doing otherwise. If we observed a rock that just hung there in the air (and we were convinced we were not hallucinating or somehow being fooled), we would not say that the rock was "disobeying" the law of gravity; we would rather conclude that there was something wrong somewhere with what we thought was the law of gravity. But of course those actions that never occur are excluded a priori from ethical consideration: we do not say that we have any sort of "ethical obligation" to accelerate towards the center of the Earth at ~10 m/s2. However we think about ethical issues, we do not construing ethical laws in the same fundamental way we construe physical laws. We cannot appeal even to psychological evidence. Even if some action were physically possible, it would still be odd to say that an action was ethical if and only if no one at all wanted to do it. People (in some sense) actually do want to murder, rob and rape other people (as evidenced by the fact that they actually do so), but it would seem odd to therefore conclude that murder was ethical. If we can't appeal to the absence of counter-evidence, we appear — absent some radical advance in epistemology — to lack any sort of epistemological foundation for deontic morality save naked assertion or divine revelation.
*I'm egregiously oversimplifying the fine details of gravity, but my point should be clear.
Naturally, noting the problems of deonticism and the failure of Myers' critique of utilitarianism are not by themselves sufficient reasons to conclude that utilitarianism, at the fundamental level, is good paradigm in which to construct a useful ethical theory; we must actually construct such a theory. I will endeavor to do so in a follow-up post.