Natural vs. Organic Functions– Review: Peter McLaughlin, What Functions Explain
In my previous post, I described the importance of a significance criteria for function ascriptions. My primary example was dueling function ascriptions for the Milky Way Galaxy. I argued that a natural function ascription for solid matter in the Milky Way Galaxy was a more significant explanation for the existence of solid matter, and the Galaxy, than an ascribing a biocentric (artifactual) function to the Galaxy. This argument rests on a presupposition that I did not explore however– that it makes sense to explain the functions of natural, but inorganic, entities at all.
Peter McLaughlin, whose What Functions Explain has spurred this series of posts, does not think that this presupposition of mine makes sense. Or at least that is the message I take from his late discussion of inorganic replicators in his book. McLaughlin writes that, “it makes no sense to speak of the function of some molecular substructure of a crystal, but we are not committed to the belief that the crystal somehow ‘benefits’ from being replicated” (2001, p. 181). Partially submerged in both of my previous posts on functional explanation is the idea that the split between natural and artifactual functions is a bit of a misnomer. In fact, the split seems to be much more between artifactual and organic functions, and so discussing functional explanation in terms of natural/artificial instead of natural/organic is a mistake. Merely being natural does not mean that something has a function, according to McLaughlin, but all organic entities do seem to have a function. McLaughlin seems to recognise this problem in his last few chapters, as once he has restricted the possession of functions to self-reproducing systems that have goods he begins to talk more in terms of organic entities that have functions and less in terms of natural entities that have them. To a degree, this problem is about semantics– if you don’t mean to include everything that falls under the category “natural”, use a different category, like “organic”!– but in a more important sense, the semantic problem reveals a real issue. Why don’t inorganic but natural entities have functions?
I think the split has been drawn between natural and artificial not just because it has a nice, dualistic ring to it, but because the terminology actually captures an important topic of metaphysics. There is a real difference between what it means for an artifact to have a function and what it means for a natural entity to have one. And, to add the kicker, that includes inorganic, but natural entities, such as the Milky Way. In my previous two posts, I have borrowed from McLaughlin function definitions that he ascribes to other authors, especially C.G. Hempel. But in the last (and very impressive) chapter, McLaughlin lets loose with a definition of his own. Answering the challenge posed in the book’s title, McLaughlin writes that functions explain “the existence and properties of those parts of a self-reproducing system that contribute to the self-reproduction of that system. What functions explain is systems whose identity conditions consist in the constant replacement, repair, and reproduction of their component parts” (2001, p. 209). This definition is meant to encapsulate organic functions only— artifactual functions are relative to the valuations of valuing agents, and (to repeat) it just makes no sense to think of the parts of inorganic systems as having functions.
I maintain that they do, and with alterations even McLaughlin’s definition of functional explanation can be made to accommodate them. Consider again my example of a system of extremely large scale– the Milky Way Galaxy. Then, expand the scale even further to that of the universe. According to most currently accepted cosmological theory, the universe is expanding, and has been since the Big Bang. Now, take the first half of McLaughlin’s definition of functional explanation– that functions explain “the existence and properties of those parts of a self-reproducing system that contribute to the self-reproduction of that system”– and integrate that thought with the idea that the universe is expanding. The universe is expanding, and (barring a misunderstanding, which, given the subject, seems almost inevitable), this means that there are parts of the universe that contribute to that expansion. These parts are parts of a self-reproducing system (the universe), that by their very existence, contribute to the self-reproduction and expansion of that system. Note that this would not be the case if the universe was in a steady state or in the process of collapsing into a Big Crunch sometime in the future.
There are clearly some enormous, massive difficulties in the details of this example. We don’t know what the stuff is that is causing the universe to expand. Some (a very small amount) of that universe seems to be matter of the kind with which we are used to dealing– solids, liquids, and gases– but most of it is apparently other stuff. Because I am not an expert Cosmologist, I cannot hope to explain these details. The expert cosmologists themselves seem to be at a loss, as well, but at least they have some ideas of how to work on these problems. What is important for my use of this popularly scientific understanding of cosmology is this: the Universe, the largest natural, physical, and (largely) non-living thing that can be conceived, seems to be a system that has parts that have functions. Many of those parts, being the structure of the universe, are just like it– they are natural and non-living. Yet they seem to be function bearers, at least with the first half of McLaughlin’s definition in mind.
At this point, you might be wondering if the universe, as a system, satisfies the second part of McLaughlin’s definition. Is the universe the sort of system “whose identity conditions consist in the constant replacement, repair, and reproduction of [its] component parts”? The rub for non-living systems in the definition seems to be the criteria of “replacement” and “repair”, included by McLaughlin in order to 1) distinguish natural functions from artifactual functions and 2) generalise the causal feedback loop required by functional explanations from requiring natural selection (which itself requires inter-generational reproduction) to intra-generational processes like the gradual maintenance of organs in living creatures (McLaughlin, 2001, pp. 179-190) This itself is an adaptation of a Maynard-Smith’s conditions for life, namely replication, regeneration, metabolism, and growth (Maynard-Smith, 1986). Regeneration, repair, or maintenance– no matter how you formulate the condition, it does not seem as if it is the kind of thing that can be assigned, broadly, to most parts of the universe. Which is why I suggest that we jettison the repair condition.
My motive for this is that parts of natural, non-living systems do seem to have functions. For the most part, except for this one criteria, parts of such systems meet the requirements that must be met by function bearers. The reason that I think natural, non-living entities should be included as possible subjects of functional explanation is that such explanation can be useful in providing more information about the universe. We are paying a heavy explanatory cost by limiting (severely limiting!) functional explanation of natural entities to living entities. Most of the universe is non-living, and we need all the information about it that we can get.
We do have to go about this sort of explanation in the right way. To lower the metaphysical costs of functional explanation, as well as to make the explanation more complete, we should be careful to limit (if not eliminate) intentional teleology, as well as anthro- or bio-centric perspectives, from functional explanations. Appealing to causal feedback loops as a primary ingredient of functions is currently the best way to achieve this goal. It is also important to keep the distinction between natural and artifactual functions, as one has an internal teleology and the other an external teleology, related to that of an external valuing agent. The primary objection to jettisoning the repair condition from a definition of natural functions is that by doing so one not only brings in natural but non-living entities but also artifacts. How do I propose to keep the distinction between natural and artifactual functions while rejecting the repair criteria? By building in a significance criteria. To get the most information out of an explanation, we should employ the variety of functional explanation that has the most significance for the system being explained. For a bicycle, an artifactual explanation is the most significant, and for the universe, a natural explanation is the most significant. It is not necessary to build into our definition of function that there is a distinction between artifacts, living entities, and non-living entities. We lose much by insisting that only one kind of functional explanation is possible for artifacts, another is possible for living entities, and no functional explanation is possible at all for non-living, natural entities. If we are truly motivated to accept a definition of functional explanation with the greatest explanatory range and power, and the lowest metaphysical cost, then we should not require that the subjects of such explanation be living if they are natural.