Functionalist explanations in biology and law

Over at Legal Theory Blog, the indefatigable Larry Solum has an entry on functionalist explanations in legal theory. It’s overall a great entry, but I wanted to comment on the section describing the role of functionalist explanations in evolutionary biology:

Functionalist explanations are familiar to almost everyone, because of the important role they play in evolutionary biology. When we try to explain why an organism has a particular trait–why male peacock’s have their colorful feathers or why the elephants have trunks–we appeal to the function that the trait serves. Male peacock’s have colorful feathers because that trait serves to attract female peacocks and hence the genes produce this trait are favored by evolution. Elephants have trunks, because they enable elephants to eat and drink more efficiently.

In biology, functionalist explanations are scientifically valid, because we understand the causal mechanism whereby function plays a causal role. That causal mechanism is evolution, of course, and we have a very good explanation for how evolution works in the form of genetics. DNA (plus a lot of other stuff) provides the precise causal mechanism by which evolution operates.

This account and the subsequent discussion of similar explanations in law and humanities immediately reminded me of the philosopher John’s Searle’s work on functions, formulated in his book The Construction of Social Reality.  Aside from being generally fascinating (and I think correct), Searle’s account of functions has some bearing on how we think of functionalist explanation in legal theory.  (Disclaimer: John Searle was my undergraduate thesis advisor).

Searle’s argument, in a nutshell, is that functions (unlike causes) are not intrinsic to natural phenomena; functions are always imposed by observers and they exist only relative to a particular teleology.  If Searle is right, then functionalist explanations — even those that purport to describe intrinsic facts about nature or other phenomena — may often say more about the explainer’s value system than about the phenomena that’s being explained.

Since I haven’t found any in depth accounts of Searle’s theory of functions online, I’ll try to cover some of it in this post.  I’ll start by giving a quick rundown of two interesting parts of Searle’s account of functions: first, his argument that functions are observer-relative rather than observer-independent, and second, his claim that evolutionary explanations are not functionalist explanations in the most relevant sense.  I’ll conclude by sharing some thoughts about what Searle’s account might mean for functionalist explanations in legal theory.

Searle’s account of functions

Searle makes two points about functionalist explanations (in biology and elsewhere) that are relevant here.  I’ll cover them in turn.

1. Functions are observer-relative

First, Searle argues that functions are not intrinsic to nature but rather assigned by observers. Or, as Searle puts it, a “function” is always an observer-relative fact about the world rather than an observer-independent (i.e., ontologically objective) fact about the world.  When we use the term “function” in an explanation, then, we may be revealing more about our values than about the intrinsic nature of the thing we’re trying to explain.

This, surprisingly, is true even for functional explanations in biology.  Take the explanation, “the function of the heart is to pump blood.”  Is it an observer-independent description of the heart’s intrinsic features, or is it an assertion of particular community’s value-system?  Here’s Searle’s take:

It is … intrinsic to nature that the heart pumps blood, and causes it to course through the body. It is also an intrinsic fact of nature that the movement of the blood is related to a whole lot of other causal processes having to do with the survival of the organism. But when, in addition to saying “The heart pumps blood” we say, “The function of the heart is to pump blood,” we are doing something more than recording … intrinsic facts. We are situating these facts relative to a system of values that we hold. It is intrinsic to us that we hold these values, but the attribution of these values to nature independent of us is observer relative.  Even when we discover a function in nature, as when we discovered the function of the heart, the discovery consists in the discovery of the causal processes together with the assignment of a teleology to those causal processes. This is shown by the fact that a whole vocabulary of success and failure is now appropriate that is not appropriate to simple brute facts of nature. Thus we can speak of “malfunction,”“heart disease,” and better and worse hearts. We do not speak of better and worse stones, unless of course we have assigned a function to the stone. If we use the stone as a weapon or a paperweight or an objet d’art trouvé, for example, we can asses its adequacy under these functional descriptions.

(All quotes are from Searle’s The Construction of Social Reality).

To be clear, Searle is not denying that the heart causes blood to pump, and I don’t think he’s arguing that biologists should abandon the use of the term “function” in this context.

Searle is, instead, pointing out that the vocabulary of functions is inherently observer relative: it always assumes a teleology and a background value system.  The heart causes many things: thumping noises, blood circulation, and so on. When we choose to describe just one of those causes as the heart’s “function,” we reveal something about our value system — we prefer life and the things that promote it, like blood circulation.  And indeed, if we had a different value system, we would very likely describe the heart’s function differently:

It is because we take it for granted in biology that life and survival are values that we can discover that the function of the heart is to pump blood. If we thought the most important value in the world was to glorify God by making thumping noises, then the function of the heart would be to make a thumping noise, and the noisier heart would be the better heart. If we valued death and extinction above all, then we would say that a function of cancer is to speed death. The function of aging would be to hasten death, and the function of natural selection would be extinction. In all these functional assignments, no new intrinsic facts are involved. As far as nature is concerned intrinsically, there are no functional facts beyond causal facts. The further assignment of function is observer relative.

In a nutshell, then, Searle’s first argument is that functions only exist relative to an observer’s value system, or teleology — functions are never intrinsic to natural phenomena independent of observers.  The obvious implication for our purposes is that functionalist explanations, which are often presented as descriptive accounts of the world, are likely to be normative or (at least) value-laden: they assume a particular set of community values, and their persuasiveness depends not merely on the existence of brute facts about nature but also on the acceptance of the value-system that’s implied.

2.  Evolutionary biology does not rely on functionalist explanations

The second of Searle’s arguments I want to cover is about the nature of explanations in evolutionary biology. As discussed above, Searle has made a strong case that functionalist explanations are always observer-relative.  Now Searle has to account for the fact that explanations in evolutionary biology often use the language of functions, even though they very effectively explain observer-independent phenomena.

Searle’s answer to this puzzle, on my reading, is that explanations in evolutionary biology aren’t functionalist in the sense that matters.  That is to say, evolutionary explanations (unlike functionalist arguments) don’t derive explanatory force from the existence of functions in nature.  Instead, evolutionary explanations work by describing brute, observer-independent causal processes at multiple levels of abstraction.  In fact, the genius of Darwin’s theory of evolution and natural selection is precisely that it strips naturalistic explanations of all teleological assumptions. Here’s Searle:

One of Darwin’s greatest achievements was to drive teleology out of the account of the origin of species. On the Darwinian account, evolution occurs by way of blind, brute, natural forces. There is no intrinsic purpose whatever to the origin and survival of biological species. We can, arbitrarily, define the “functions” of biological processes relative to the survival of organisms, but the idea that any such assignment of function is a matter of the discovery of an intrinsic teleology in nature, and that functions are therefore intrinsic, is always subject to a variant of Moore’s open-question argument: What is so functional about functions, so defined? Either “function” is defined in terms of causes, in which case there is nothing intrinsically functional about functions, they are just causes like any others. Or functions are defined in terms of the furtherance of a set of values that we hold—life, survival, reproduction, health—in which case they are observer relative.

(Note that Searle is using “function” and “teleology” or “purpose” somewhat interchangeably at this point in the book.  This makes sense: if you agree with Searle that functions are observer relative, then all functionalist accounts imply a teleology.)

Searle’s point, again, is that evolutionary explanations are specifically non-teleological.  This makes explanations in evolutionary biology different from functionalist explanations. To the extent evolutionary explanations use the vocabulary of functions, they draw little or no explanatory force from that vocabulary.  Explanations in evolutionary biology instead derive their force from the coherent causal story they provide — including causal relationships (such as those between genetic, individual and species survival; natural selection and evolution; etc.) that occur at multiple levels of abstraction and at different temporal scales:

From a philosophical point of view, the marvelous thing about Darwinian evolutionary biology was not only that it drove teleology out of the biological explanation of the origin of species but that it gave us a new kind of explanation, a form of explanation that inverts the order of the explanatory apparatus. So, in pre-Darwinian biology, we would say, for example, “The fish has the shape that it does in order to survive in water.” In evolutionary biology we perform an inversion on that intentional or teleological explanation, where we substitute two levels of explanation. First, the causal level: We say the fish has the shape that it has because of its genetic structure, because of the way the genotype, in response to the environment, produces the phenotype. Second, the “functional” level: We say that fish that have that shape are more likely to survive than fish that do not.  Thus, we have inverted the structure of the explanation. The original structure was, the fish has this shape in order to survive; now we have inverted it: the fish is going to have this shape anyway, but fish that do have this shape are more likely to survive than fish that do not. Notice what we have done in the inversion. Survival still functions as part of the explanation, but now it is introduced into the explanation diachronically. It functions over a period of many generations, and its causal role is inverted. Because the teleology is now eliminated, survival is not a goal that is pursued but simply an effect that happens; and when it happens it enables the reproduction of the survival-producing mechanisms.

The brilliance of Darwin’s theory is that — unlike most functionalist explanations — it explains nature causally, rather than teleologically.  In that sense it is hermetic — observer-relative values don’t need to play a role in evolutionary explanations the way they do in most functionalist explanations.  As Searle points out, this is true even for concepts such as “survival.”  Under Darwin’s theory of evolution, survival is not an inherent function of living things or an overarching value of natural phenomena. Survival is instead an effect that happens, and one that enables reproduction of the survival-producing mechanisms.

Those mechanisms are themselves explained wholly causally — and indeed, we can explain the entire evolutionary process that leads to, say, a fish’s shape, without any assumptions about an overarching teleology, value system, function, or goal.

What Searle’s account means for functionalist arguments in legal theory

The two arguments described above are a very small piece of Searle’s broader project in The Construction of Social Reality (and subsequent works), which is to provide an account of the ontology of human institutions, from money and marriage to games and governments.[1] While these two arguments were not intended as critiques of functionalist explanations in the law and humanities, I do think they have some practical implications for how we evaluate such explanations.

First, Searle’s point that functions are observer-relative suggests we should always be on the lookout for the teleological assumptions underlying a functionalist explanations. While functionalist explanations often purport to describe objective cause and effect relationships, they just as often rely on normative or teleological assumptions for their force. Sometimes, as with self-described Marxists explanations of institutions, the underlying teleology is explicit, and we know where to look for it (start with Das Kapital, etc.). Other times, as with many modern economic analyses of the law, the teleology (e.g., a preference for maximizing efficiency or for free market mechanisms) may sometimes be presented as an intrinsic feature of the world rather than a value framework preferred by the author.  In almost all cases, the persuasive force of the functionalist argument depends on acceptance of the underlying teleology, rather than on the mechanical details of the functionalist story.

Second, Searle’s account demonstrates some of the dangers of injecting terminology from evolutionary biology into social science and legal explanations. Despite it’s use of functionalist vocabulary, evolutionary biology derives its explanatory force from the fact that it presents a coherent, observer-independent, complex causal account of the world around us that is consistent with the weight of empirical evidence.  Evolutionary explanations don’t rely on any intrinsic teleology to be persuasive.  Their persuasiveness hinges wholly on their consistency with brute facts.

By contrast, functional explanations in the social sciences, as elsewhere, derive at least part of their force from a teleology or a specific set of values.  We should therefore be very careful when we see the language of science used to discuss social or legal phenomena to lend “objectivity” to what may ultimately be a normative account.

Of course, none of this is to say that functionalist explanations are bad, just that they often require additional unpacking.  And it is not to say that Searle believes an objective account of humanities — institutions like laws, schools, money, and so on — is impossible.  The rest of his book is, in fact, an effort to draw the broad outlines of what such an account would look like.  There’s quite a bit more to Searle’s account, which I’m skipping over for the sake of brevity.  I encourage those who are interested to go straight to the source (and at the time of this writing, an early chapter of The Construction of Social Reality is available here).

[1] One point of disambiguation for those who have read the book: while Searle’s theory of institutions relies on the terminology “status functions,” Searle’s account of human institutions is ontological rather than functionalist — he argues institutions exist by virtue of collective acceptance of certain deontological relationships of power, duties, rights, roles, etc., and calls those “status functions.”  In other words, he does not claim that institutions exist because they serve particular functions, he argues that institutions exist (and perform particular functions) because people collectively believe them to exist.