Are Biological Functions Observer-Relative?

The following three positions need to be distinguished:

Theists who rely on design arguments subscribe to (1), while some naturalist philosophers come out in favor of (2). (2), however, involves the claim that there is intrinsic design in nature, a claim that is far from obvious, and is arguably inconsistent with Darwinism. The point of Darwinism is that what looks to be designed, in reality is not, but can be accounted for in terms of mechanistic, non-teleological processes of random variation and natural selection.  If we are using the term 'design' strictly and without equivocation — and thus not confusing 'design' in the present sense with 'design' in the sense of pattern or shape — then nothing can exhibit design unless there is a designer responsible for the thing's design.  If someone were to say that natural selection designed birds' wings so that they can evade their predators they would be gulty of a two-fold fallacy: first, the fallacy of hypostatizing natural selection, and second, the mistake of supposing that birds' wings exhibit an intrinsic designedness.

So it looks as if (3) is the correct view. The following considerations will be based on passages from John Searle's The Construction of Social Reality (The Free Press, 1995). We consider the case for the contention that there are no intrinsic design features in nature, equivalently, that biological functions are observer-relative.

Suppose the object is a screwdriver. Its being a screwdriver is not intrinsic but relational: it is only in relation to an observer or user or fabricator that a screwdriver is a screwdriver. Of course, nothing can be a screwdriver unless it has certain intrinsic properties that fit it to play this functional role: one cannot make a screwdriver out of ice or spaghetti. Not even an Eskimo or an Italian could do it. But the property of being a screwdriver is not intrinsic to the object. It is an observer-relative feature.  This is not to say that I can make a thing a screwdriver just by wishing it to be one or thinking it to be one.  The point is that nothing is a screwdriver apart from a context of tools (ein Zeugzusammenhang as Heidegger would say) which refers necessarily to tool-users, purposive beings such as us.

As Searle puts it, the property of being a screwdriver is epistemically objective but ontologically subjective. (p. 10) Thus it is objectively true that the tool in my hand is a screwdriver, but its being a screwdriver necessarily involves a reference to a subject who uses it as such.  Nothing is a screwdriver or a jackhammer or a modem intrinsically.

Here is a rough-and-ready test to determine whether a property is intrinsic or observer-relative: Could the property exist if there had never been any human beings or other sorts of sentient beings? (p. 11) The property of being a screwdriver could not exist (be instantiated) in a world in which there were no sentient beings. This ought to be obvious. A screwdriver is an artifact designed for the purpose of inserting screws by beings who make plans and have purposes. In a world without such purposive beings there would be no tools of any kind. There might be rocks, ponds, fires, and forests, but no paperweights, swimming holes, heaters, or fuel sources.

2. Searle's point about functions is that they are never intrinsic but always observer-relative. Functions are assigned or imposed by us. A burro (my example) is not intrinsically a beast of burden but is susceptible to having that functional role imposed on it. Or else we fabricate a mechanical 'burro' to suit our purposes.  Similarly, cats and dogs are not pets intrinsically: the pet role is imposed by us.

There are no functions in the natural world: "nature knows nothing of functions." (14). Hearts occur in nature, and it is an observer-independent fact that they cause blood to course through the bodies that house them. But the function of the heart to pump blood is not intrinsic to nature.

One consideration in support of this view is that things in nature cannot be said to either fail or succeed in exercising their function. You cannot say of a piece of metal in nature that it failed or succeeded since there is no job or function that it was supposed to perform. But one can say of a metal rivet that it failed or succeeded. ('The main rivet failed and that triggered a series of events that led to the collapse of the bridge.') Normative talk is now appropriate. Only things having functions can malfunction. Depending on its size and shape and weight, a rock may make a good or bad weapon once we assign it the weapon function. But a rock in nature is neither good nor bad since there is nothing that a rock in nature is FOR. There are no weapons or paperweights or door stops in nature.

As Searle puts it, "functions are never intrinsic to the physics of any phenomenon but are assigned from outside by conscious observers and users." (14) But wasn't the function of the heart, namely, to pump blood, discovered? Now if a function is discovered, how can it be "assigned from the outside"?

Although it is true to say that we discover the functions of organs and the like, "the discovery of a natural function can only take place within a set of prior assignments of value (including purposes, teleology, and other functions)." (15) The natural facts are exhausted by the causal facts. The functionality of the heart is something we add to the natural facts. So although one does discover how the heart works — its mechanism — one does not discover any teleology. Searle:

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 that 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. (15)

3. Searle thinks that Darwinism supports his contention that functions are never intrinsic, but always observer-relative:

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. (16)

Searle could draw on the authority of experts like Ernst Mayr who also insist that Darwinian theory results in the expulsion of Aristotelian final causes.

4. Compare airplane wings and eagles' wings.  The wings of an airplane are designed by human engineers for a purpose: to generate lift so that a heavier-than-air craft can become airborne.  They are for flying. Now it might seem that the same is true of eagle's wings: they too are for flying.  This is true, but only relative to us.  Because we value mobility and survival, we project onto the eagles' wings the function of being for flying and escaping predators.  Searle's point, however, is that nothing in nature intrinsically has a function.  He is not saying that airplane wings have a purpose while eagles' wings don't: they both have a purpose, but it is observer-relative.  In a world without beings like us, bird's wings and birds' nests would exist and have causes and effects but lack functions.