LEE MCINTYRE
THE EMERGENCE OF THE PHILOSOPHY OF CHEMISTRY ?
ABSTRACT. After a long period of neglect, the philosophy of chemistry is slowly being recognized as a newly emerging branch of the philosophy of science. This paper endorses and defends this emergence given the difficulty of reducing all of the philosophical problems raised by chemistry to those already being considered within the philosophy of physics, and recognition that many of the phenomena in chemistry are “epistemologically emergent”.
The philosophy of chemistry has been a long neglected field. Indeed, much of the excellent work done in this area over the last few decades has been forced to contend with the prejudice that there is no such field as the philosophy of chemistry.1 Recent events, however, have belied such skepticism and have lead to an increased awareness of the emergence of this discipline. A recent symposium organized for the Boston Colloquium for the Philosophy of Science on the emergence of the philosophy of chemistry, the appearance of an entire special issue of the journal Synthese devoted to issues within the philosophy of chemistry, and the founding of the present journal – which shall be exclusively devoted to the philosophy of chemistry – are important milestones in the acceptance of the philosophy of chemistry as an independent discipline within the philosophy of science. It is important to realize that the philosophy of chemistry is finally being recognized as an autonomous subject. Of course, this immediately raises the question: “why has it been so long neglected?” That is what I would like to discuss in the present paper. The fate of the philosophy of chemistry has been inextricably linked with that of the philosophy of science in general, which itself only emerged as a discipline separate from epistemology in about the 1920s. The philosophy of physics has existed since the beginning ?
An earlier version of this paper was read at Boston University on November 5, 1997. Foundations of Chemistry 1: 57–63, 1999. © 1999 Kluwer Academic Publishers. Printed in the Netherlands.
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of the philosophy of science. Indeed, it was probably the desire for philosophical precision in considering the foundational questions of physics near the turn of the century that gave the philosophy of science its impetus. The philosophy of biology came along somewhat later, in the 1960s, with the work of David Hull, Michael Ruse, and others, and led to the journal Biology and Philosophy. However, there is one foundational science that is missing here. Traditionally, the dominate triumvirate in the natural sciences has been physics, chemistry, and biology. Indeed, in the great hierarchy of the disciplines, it is often held that chemistry is more foundational than biology. So, if there is a philosophy of biology, why hasn’t there been a philosophy of chemistry? To answer this question, I think, one must delve into the historical relationship between chemistry and physics. While biology has always struggled to assert the autonomy of its subject matter, and even at times the separateness of its methodology, chemistry has often been thought of as a runner up to physics. If biology is the kid brother – born to rebel and to establish its legitimacy as a science on its own terms – chemistry has been the proverbial “middle child”, forced to grow up in the shadow of its overachieving older sibling. Uncharitably, some have argued that chemistry is just “applied physics”, or, fresh from a breakthrough in theoretical physics, it has been announced haughtily that “the rest is chemistry”. These and similar remarks, I am sure, are well known and grow out of the confidence that physical explanations are always superior to chemical ones. The ontological dependence of chemical relationships on physical ones has more or less determined the fate of chemistry as an explanatory enterprise and, in turn, has led to the false assumption that chemistry raises no interesting philosophical questions of its own. Indeed, the relationship between chemistry and physics is widely taken to be a paradigm case for reductionism, whereby the entire content of chemistry is thought to be perfectly reducible to that of physics. That it has not been so reduced already is argued simply to be a matter of efficacy. Thus, it is felt by many that the philosophy of chemistry is superfluous – that since chemistry is perfectly reducible to physics, then any potential issues within the philosophy of chemistry must already be being considered within the philosophy of physics. Now
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this would not be so bad, except that a quick glance at the philosophy of physics shows that it is pretty well dominated by three issues: special relativity, quantum mechanics, and space-time.2 Is one, therefore, justified in having confidence that any interesting philosophical issues that might be raised within the philosophy of chemistry are already being considered within the philosophy of physics? Aren’t there any interesting philosophical questions raised by chemistry on its own? Doesn’t the philosophy of chemistry deserve to be an autonomous discipline? And, if not, then why hasn’t chemistry already been reduced to physics? That is, if chemistry is not really very different from physics, then why does it have as much explanatory autonomy as it has? Moreover, if one is prepared to reject the philosophy of chemistry – on the grounds that the subject matter of chemistry is ontologically dependent upon physical relationships – shouldn’t one then be prepared to make the same sort of argument, in principle, about the philosophy of biology? Does the defense of the philosophy of biology depend upon our belief that there is some sort of mysterious ontological break between the subject matter of biology and physics? Should we return to vitalism? A host of philosophers of biology will give you a fight on that one! In the philosophy of biology, we recognize the sense in which biological phenomena are ontologically dependent upon physical relationships. And yet, we rightly insist that biology is more than just “applied physics” or even “applied chemistry” – that biological phenomena deserve to be explained in their own descriptive terms. May we not, therefore, embrace the idea that in the study of chemical relationships, we should allow for a similar degree of explanatory autonomy? Despite their many differences, biology and chemistry seem to be in much the same position relative to their respective ontological dependence upon physics, yet we nonetheless sanction the explanatory autonomy that makes them autonomous sciences. Why, then, should we treat them so differently on philosophical grounds? If the ontological dependence of biological phenomena upon physical relationships is not taken to preempt the philosophy of biology, then why would one think that the in principle reducibility of chemistry to physics would preempt the philosophy of chemistry?
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In a recent paper, Eric Scerri and I have argued that there are a number of legitimate philosophical issues that are raised by chemistry, and that the existence of the philosophy of chemistry can therefore be defended as an autonomous branch of the philosophy of science.3 Indeed, it is important to note that the philosophical issues raised by the science of chemistry deserve to be considered even if it is in fact true that chemistry is, in principle, reducible to physics. As philosophers have recently learned from the ongoing debate over supervenience and non-reductive materialism in the philosophy of mind, ontological dependence need not compel reductive explanation. Let me explain what I mean by this: there is a heated and ongoing contemporary debate in the philosophy of science and the philosophy of mind over the terms and need for reductive explanation. On the one hand, there are those who suppose that strict ontological dependence between two different levels of analysis is all that is needed for reductionism. If one may, in principle, reduce the subject matter of one science to another, then that is an explanatory goal to be embraced. On the other hand, however, there are those who believe in the “emergence” of phenomena at the secondary level of description, that would be lost at the primary level of description, even if it is also true to say that the phenomena at the secondary level are perfectly ontologically dependent upon relationships at the primary level. Now, what does this mean? Well, what it does not mean is that there must be some sort of mysterious ontological break between the primary and the secondary levels. Throughout the philosophical literature, there has been a lot of cheap talk about “emergence” that seems to have implied that those who support emergence are really just embracing some sort of mysterious ontological status for those entities that are both materially dependent upon physical relationships, and yet also exist “over and above” them. The emergentist slogan that “the sum is greater than the whole of its parts” has been thought to imply a commitment to some ethereal metaphysical thesis about the ontological autonomy of aggregate phenomena. This position was staked out long ago by the “vitalists” and the “animists” in biology, and has long since been repudiated. In the debate over the status of “consciousness” in the philosophy of mind, it is currently
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being fought by the eliminativists and, for want of a better word, the “dualists”. But there is a third position. For one may also support emergence as an epistemological matter. That is, one may agree that there is an important sense in which phenomena at the secondary level of description would be lost if they were to be reduced to the primary level, and yet eschew the idea that this necessitates any sort of ontological break between the primary and the secondary level. Instead, one may fully support the strict ontological dependence of phenomena at the secondary level upon those at the primary level, and yet support emergence as a matter of explanatory efficacy. For what really is the point of reduction? It is a thesis about the value of explanations that unify phenomena across diverse levels of description. Where we are able, we reduce one theory to another because there is explanatory virtue in doing so. But what should we do in those instances where such reduction would require that we try to capture well-defined regularities that exist at the secondary level of description in terms that would seem to obscure or even eclipse the very regularities that we are trying to explain? In such instances we must respect the “epistemological emergence” of the phenomena at the secondary level; we may admit that the ontological dependence of secondary phenomena upon primary relationships would allow us in principle to reduce, if we cared to. However, what we must also see is that in some cases there would be no explanatory purpose for doing so. The above discussion illustrates the position we are in for the explanation of “consciousness” in the philosophy of mind and in the way that we account for “life” in the philosophy of biology. Now, I think we should be prepared to admit that this is also our position with respect to several of the phenomena we wish to explain in chemistry. Indeed, I think there is great philosophical value in admitting to this and to find within the philosophy of chemistry a way for us to explore the philosophical issues that are raised by the concepts of “reductionism” and “emergence” in their most basic terms. That is, in the philosophy of chemistry, just as in the philosophy of biology or the philosophy of mind, even if we are prepared to reject the idea that there are “ontologically emergent” phenomena raised by our science, this need not convince us that there are no
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“epistemologically emergent” phenomena to be considered. Indeed, the very issue of reductionism – considered within the context of the relationship between chemical and physical explanations – is perhaps not as straightforward as one may think. Is the relationship between physics and chemistry a blatantly obvious paradigm case for reductive explanation? Perhaps here we face our first issue in the philosophy of chemistry! Other issues that potentially may be raised by the philosophy of chemistry include the question of whether there can exist independent “laws” of chemistry (and consequently the fascinating question of whether one can have two sets of laws both explaining the same regularity), the potential autonomy of chemical explanations, the debate over whether (and which) chemical concepts might be considered to be “epistemologically emergent” (and therefore, non-reducible to their physical counterparts), and the question of whether the relationship between chemistry and physics is captured by supervenience. Of course, the existence of the philosophy of chemistry as an autonomous discipline does not presuppose any particular position in any of the above debates. One would expect that in the philosophy of chemistry, as in every other philosophical discipline, there would be a healthy diversity of beliefs. Thus, except for the rather doctrinaire dismissal of the philosophy of chemistry as an illegitimate area of concern, this field could and should tolerate many lines of research. Indeed, ultimately, this is perhaps the strongest argument in favor of the philosophy of chemistry. For as such debates persist, critics of the philosophy of chemistry would find themselves in the uncomfortable position of having to deny the existence of a field in which philosophical debate is already taking place! Such, I argue, is where we now find ourselves with respect to the existence of the philosophy of chemistry. It does not need to be argued that the philosophy of chemistry should be founded – since it has already emerged. It need no longer be the neglected sibling of the philosophy of science. Whether it will remain so is up to the efforts of its practitioners and to the willingness of the larger community within the philosophy of science to accept it.
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NOTES 1. For a comprehensive bibliography of past work in this field see Eric Scerri’s excellent “Bibliography on Philosophy of Chemistry”, Synthese, Vol. 111, #3, (June 1997), pp. 305–324. 2. David Hull, “Philosophy of Biology” in P. Asquith and H. Kyburg Jr. (eds.) Current Research in Philosophy of Science, East Lansing, Mich.: PSA, 1979, p. 421. 3. Eric R. Scerri and Lee McIntyre, “The Case for the Philosophy of Chemistry”, Synthese, Vol. 111, #3, (June 1997), pp. 213–232.
Department of Philosophy and Religion, Colgate University, Hamilton, NY 13346
