An Introduction to Evolutionary Ethics (3 page)

In a single stroke, the idea of evolution by natural selection unifies the realm of life, meaning and purpose with the realm of space and time, cause and effect, mechanism and physical law. It is not just a wonderful idea. It is a dangerous idea.

(Daniel Dennett, Darwin's Dangerous Idea)
To be human: To be the place where the falling angel meets the rising ape.

(Terry Pratchett, Hogfather) In order to get some traction on the question of natural selection's role in the development of our moral psychology, we first need to refresh ourselves on the basics of Darwin's theory. In this chapter we review some of the basic features of evolution by natural selection. We will not bother too much with the details. What's important is to highlight the general principles that have led some moral psychologists to claim that evolution played a critical role in shaping our moral mind. I'll start with the general story, which is actually quite easy to tell. Then, with that story firmly in place, I'll dispel some common misconceptions about the view. In the final sections, I'll explore the ways in which this story has been extended to psychology, where it is claimed that, like our bodies, our minds contain specialized adaptations.

1.1 The Basic Story At the center of what might be called the Darwinian Revolution, amid the myriad details and disputes, refinements and revisions, field tests and computer models, is a very simple, very elegant idea. Here's a glimpse of it in Darwin's own words: More individuals are born than can possibly survive. A grain in the balance will determine which individual shall live and which shall die, – which variety or species shall increase in number, and which shall decrease, or finally become extinct. (Darwin 2003/1859: 467) Buried in this passage are three conditions on which the entire edifice of evolution by natural selection stands:
variation
,
differential reproduction
, and
inheritance.
Let's look closely.

One background assumption, left unstated in the passage, is that the number of reproducers in a given population will eventually outgrow an environment's resources; hence, “more individuals are born than can possibly survive.” But, Darwin implies, all individuals are not created equal: speed, strength, coloration – these
vary
within a population. Some (but
only
some) of these variations – in the particular environment individuals inhabit – will over time alter an individual's reproductive success; there will be, that is,
differential reproduction
within a population. For example, the individual moth that happens to be grey tends to be overlooked by predators in her environment, whereas the individual moth that happens to be white makes for an easy meal in that same environment. That tiny difference in color, that “grain in the balance,” may well affect not only that individual's chances of survival and reproduction, but the makeup of the species as a whole. Why? Because if we assume that variation in color can be
inherited
, then offspring will tend to exhibit that color variation as well. And since grey moths have a small reproductive advantage over white moths, grey moths (all things being equal) will come to dominate the population. Mother Nature will “select against” white moths in that environment. In sum, some
variations
that occur naturally among reproducing organisms improve an individual's
rate of reproductive success
in relation to its neighbors; when these fitness-enhancing variations are passed on to offspring, you have evolution by natural selection.
¹

As simple and mindless as this process may sound, its power is hard to overstate. The evolutionary biologist Theodosius Dobzhansky went so far as to claim that “nothing in biology makes sense except in the light of evolution” (1964: 449). First, the theory offers a direct and uncluttered explanation for much of the diversity of organic structures we observe across time and across the biological world, an explanation that does not draw on anything more controversial than, say, the workings of genes. With enough time, the pressures of an unforgiving environment – together perhaps with picky neighbors – will yield any number of exotic forms, from flying squirrels to jellyfish to redwoods.

Second, the theory delivers what was once thought
un
deliverable: an explanation of design that does not depend on a designer. Who could deny that the human eye or the finch's beak is exquisitely suited to its environment? It would seem from any commonsense perspective that that fit
had
to be the result of some kind of engineer, someone who understood both how the design would integrate with the other workings of the organism and how it would mediate the organism's interaction with its environment. But that perspective is distorted by, among other things, our place in time. Were we capable of “rolling back the tape” and observing each generation, with its incremental alterations and minor reproductive successes, we would find the development of the human eye, for example, almost unremarkable. The philosopher Daniel Dennett (1995) compares the process to selecting a tennis champion. How does every tennis tournament always select a champion? Easy, she's the last person standing after all the rounds. Remember: we do not see the 99 percent of genetic mutations that do
not
advance an organism's fitness; we only see the “winners.” Success in design is inevitable and ubiquitous for the simple reason that creatures ill suited to their environment have, as the philosopher W.V. Quine put it, “a pathetic but praiseworthy tendency to die before reproducing their kind” (1969: 126).

Finally, the core logic of evolutionary explanations is not limited to the shape of organs or the strength of bones, but extends rather smoothly to observable
behaviors
. Beginning in the 1960s, biologists following the work of Konrad Lorenz and Nikolaas Tinbergen developed methods of analyzing the underlying structure of animal behavior, a field that came to be known as
ethology
. Here, critical focus was directed on the adaptive purpose(s) of certain behaviors, for example, the phenomenon of “imprinting” observed in ducklings.
²
The assumption among ethologists was that there existed a series of evolutionary events – or
adaptive pressures
– that ultimately led to the behavior. This would explain, if anything did, what the behavior was for. And this in turn might aid in understanding the developmental influences that lead to the expression of the behavior in individuals.

From here, it is only a few short steps back to our main subject: the human moral sense. (For the time being, think of a
moral sense
as a tendency to make moral judgments and experience moral sentiments.)
If
– and I stress the
if
– one wanted to argue that our moral sense is the product of evolution by natural selection, the general shape of the argument must look something like the following. Through the process of genetic variation, some individual (presumably some early hominid) developed something approximating a moral sense. While perhaps only slightly distinct from its evolutionary precursor, that sense enabled its possessor to survive and reproduce at a rate that exceeded, if only slightly, the rate of her neighbors. Left unchecked, the process of natural selection yielded a population dominated by individuals who possessed this moral sense.

Let me emphasize, however, two things: first, this argument amounts to little more than a general schema; all of the details needed to make this argument remotely plausible have been left out. In later chapters we will explore these details. Second, one could maintain that evolution by natural selection contributed to the development of our moral sense, but only
indirectly
. Two positions present themselves.

One of the positions that we will discuss later asserts that our moral sense was, if you will, a “by-product” of some other system that was directly selected for. As a point of comparison, consider the color of human blood. No one seriously believes that the redness of human blood was directly selected for. What was directly selected for was the oxygen-carrying properties of blood; the redness “came along for free.” That was an accidental property of blood.
³
In the same way, some wish to claim that our moral sense was an accidental property of other cognitive adaptations – for example, our capacity to reason about the consequences of our actions.

A distinct but related position states that our moral sense did evolve according to the laws of natural selection; however, the function that our moral sense originally served has been replaced (due to changes in environmental circumstances) by a more recent function, which in turn can alter its structure. A popular example of this kind of biological sleight of hand is the structure of the human lungs. Some biologists insist that human lungs originally evolved, millennia ago, to aid predatory fish in pursuing prey (Farmer 1997). But once the ancestors of these fish began their forays onto land, those “swim bladders” were well suited to respiration. Thus one might argue that our moral sense may have originally evolved to serve a purpose entirely unrelated to its present purpose.
⁴
The exact structure of these views will have to wait. In the meantime, let me warn against some common misunderstandings of Darwin's theory.

1.2 Some Common Misunderstandings The theory of evolution by natural selection does
not
entail the claim that every feature of every organism is an adaptation. It is consistent with the theory that some (some insist on many) of the organic structures we observe are not the result of the pressures of natural selection. Some are the result of random genetic mutation; others are the result of what biologists call
founder effects
, according to which a dominant characteristic (e.g. coloration) of an isolated sub-population is the result of an arbitrary feature possessed by the founders of this sub-population. So, for example, a group of green-winged finches becomes separated from the main colony of finches, only a fraction of the birds in which are green-winged. Assuming “green-wingedness” does not influence reproductive success, we will nevertheless observe “green-wingedness” come to dominate this population even though this form of evolutionary change is not the result of natural selection. Some organic changes are the result of
genetic bottlenecks
. Like founder effects, genetic bottlenecks occur when a population shrinks rather suddenly (e.g., following an earthquake), leaving only a subset of the genes of the original population.

It's worth pausing a moment to point out what these alternative processes of evolution might mean for our main inquiry. One could, for example, claim that our moral sense evolved, but that its evolution was not the result of natural selection. According to a story like this, our moral sense was not an adaptation. Its existence might be the result of a process no fancier than that which produced “green-wingedness.” If this were the case, it would be fruitless to search for the (biological) purpose of our moral sense. It has no purpose. As we move forward, it's important to keep these alternatives in sight.

Another common misunderstanding of Darwin's theory is that evolutionary change is, in some sense,
forward-looking
, or deliberate. Part of the problem stems from terminology: to say that over time organisms
adapt
to their environments strongly invites the mistaken idea that Mother Nature – or the organisms themselves – actively solve adaptive problems by altering their structure. In the standard example, the giraffe reasoned that reaching the leaves in the high trees required a long neck, and so –
voilà
! – a long neck. This of course is nowhere near the truth. We have to remember that natural selection can only “act” on those variants that happen to exist, and which variants happen to exist is quite arbitrary, since variation is by and large the result of genetic “errors” during DNA replication. This is not to deny that some organisms are exquisitely suited to their environment. But it is almost always the case that, on much closer inspection, those adaptive “solutions” are surprisingly jerry-rigged: instead of designing the most efficient or reliable or economic solution, Mother Nature appears to have rigged together pieces and parts of other existing designs (a bone here, a ligament there) to enable the organism to get by. Daniel Dennett (1995: 211) refers to them as “perversely intricate solutions.” If the raw material on which natural selection acts is genetic variation, then this is precisely what we should expect to see: tinkering. She may be clever, but Mother Nature is nonetheless a tinkerer.

1.3 Mother Nature as Tinkerer At least part of the resistance to the idea that our moral minds are the product of natural selection comes from a deep suspicion that natural selection, despite its force, could never lead to a mode of thinking as rich and emotional and powerful as moral thinking. Mother Nature is simply not that clever. One way that biologists have tried to ease this suspicion is by having us think about other more familiar processes that, despite their rigidity, produce quite original and unexpected results. Here's a common method biologists and philosophers use to loosen our resistance: Your assignment is to compose an original Petrarchan sonnet. In case you've forgotten, a Petrarchan sonnet is a poem consisting of fourteen lines; each line should contain, with only one or two exceptions, ten syllables, where every other syllable is accented. The proper rhyme scheme is:
a-b-b-a/a-b-b-a/c-d-e-c-d-e.
Although I leave the theme up to you, it is expected that the first eight lines should introduce a problem or dilemma; the remaining six lines should seek to resolve the problem.

I'm going to bet that you would not relish the thought of completing such an assignment. It's just too constricting. Even if you manage to hit upon an agreeable theme rather quickly, what promises to take up all your time is fitting that theme into the poem's rigid confines. Obviously, you can't designate in advance your rhyming words (“bird,” “heart,” “start,” “blurred”) without making your task nearly impossible. Instead, you just have to strike out in a general direction. Put some words on paper and be prepared to make lots of adjustments. You should expect of course that most of your early efforts will have to be trashed. It's not enough to find a word that rhymes with “deranged”; the word has to fit both
locally
(that is, grammatically) and
globally
(that is, thematically). In some cases, a particularly effective turn of phrase may necessitate restructuring the entire stanza. As unpalatable as this assignment may seem, I would wager that if you were to stick with it, if you were to wrestle your poetic imagination into the poem's form, you would surprise yourself. You wouldn't necessarily proclaim, “I'm a poet after all!” You would, however, produce some quite original and unpredictable lines, and apart from the music of the poem, they would express some quite original thoughts. (The price of doubting me on this, of course, is writing your own sonnet.) But the reason such an exercise is likely to yield unexpected results lies precisely in the
restrictions of the form
. Poetic “energy” has to be channeled, often in unnatural directions. The mathematician Stanislaw Ulam observed that poetic form “forces novel associations and almost guarantees deviations from routine chains or trains of thought. It becomes paradoxically a sort of automatic mechanism of originality” (1975: 180). In the process of wearing out the delete key on your computer eliminating all the obvious expressions (simply because they don't fit), eventually something clicks. It fits the meter, it sets up the rhyme, and it advances the larger theme. Ingenious! Moreover, what are the chances you would have come up with that expression in the absence of such restrictions?