The Importance of Significance for Artifactual and Natural Functions
Peter McLaughlin provides separate formulations of what qualifies an artifact as having a function and what qualifies something naturally occurring as having a function. Most arguments over functional explanation seem to center around the functions of naturally occurring entities, although the apparent necessity of separate definitions for natural and artificial entities possessing functions is not without controversy. The problem with the split between natural and artifactual functions is usually located at the split, but I think there is also a major difficulty when the two come together.
McLaughlin’s basic summation of natural functions is this:
(1) X does/enables Y (in or for some S)*
(2) Y is good for some S; and
(3) By being good for some S, Y contributes to the (re)production of X (there is a feedback mechanism involving Y’s benefiting S that (re-)produces X). (2001, p. 140)
And for artifactual functions, he provides the following schematization:
(1’) X does Y—or at leas some relevant agent believes it does.
(2’) Y is good for some S—or at least some relevant agent believes it is. (ibid)
Now, to muddy the waters a little bit. It would seem that natural entities and artifacts might be divided along lines of living and non-living things. This is not the natural entities that are living ones, but is to say that “artifact” seems to intuitively include only non-living things. After all, living things cannot be made into artifacts, right? More than that, natural things cannot be artifacts, right?
This being philosophy, the line is not nearly so clear. What about domesticated animals? On the other end, in the non-living but nonetheless natural range, what about the Milky Way Galaxy? There seems to be a large enough class of things that blur natural/artifactual distinctions that there might be a confusing proliferation of function ascriptions, not to mention difficulties in classification.
Let’s look at one of my two examples that blurs the artifactual/natural distinction, the one that is more extreme: the Milky Way Galaxy. How, you might be wondering, might the Milky Way be an artifact? Under the guidelines for artifactual function ascriptions, the Milky Way (and the rest of the Universe, for that matter) might be said to (1) provide a substrate for life and (2) that providing a home for life is good for humans. In fact, this is much of the fine-tuning argument in a nutshell. One immediate problem with this ascription of function is the insignificance of providing a home for life (at least to the best of our knowledge) to the existence of the universe. It is an explanation incredibly small in scope– to say that a function of a galaxy is to provide a home for life is similar to declaring that a function of mine was to touch a particular token at an arcade in 2004. It is to pick out a physically and temporally small occurrence in the history of an entity and hold it to be a function.
Another problem is that one can also cast a functional explanation for the Milky Way as a natural entity. (1) The Milky Way Galaxy fuses particles together in such a way that solid matter exists. (2) Solid matter is essential to maintain the shape and makeup of the Milky Way. (3) The more solid matter there is in the galaxy, the more of the galaxy there is, and without solid matter there would be no Milky Way. This certainly seems to be a more significant function of the Galaxy than providing a home for life, not to mention that solid matter seems to be more important to the actual continued existence of the Milky Way as such than the existence of life in some corner of the Galaxy. Except in a linguistic sense (without language, the Milky Way Galaxy would lose its name), there is not much that the continued existence of life does that maintains the existence of the Galaxy.
Before function ascriptions can be made for natural entities and artifacts, perhaps there first needs to be an additional guideline on how to decide which function ascription to employ. This could take the form of a significance criterion, similar to that described in Philip Kitcher’s The Advancement of Science (1993). There, Kitcher asserts that a goal of science is not simply truth, but significant truth. There are all sorts of trivial truths that are easy to arrive at, but science is after those that are significant. Similarly, to ask for an explanation of an entity’s function one is looking for the most significant of the range of explanations. While life is important to some features of the Milky Way, solid matter is much more so. Focusing on a natural function of the Milky Way explains more– it helps explain more of how the Milky Way exists at all– while an artifactual function ascription explains the Milky Way from a very unrepresentative biocentric perspective. This is not to say that the artifactual function of the Galaxy provides no information, but the natural functions of the galaxy are much more significant and provide explanations with greater depth.