The Taxonomy of the Sciences
12 April 2012
There is passage in Foucault, in the preface to the English language of The Order of Things, after the more famous passage about the “Chinese dictionary” in Borges, in which he discusses a pathological failure of taxonomy. The theme of Foucault’s book, restated compellingly in this preface, is taxonomy — taxonomy in its most general (and therefore its most philosophical) signification. Taxonomy is a problem.
It appears that certain aphasiacs, when shown various differently coloured skeins of wool on a table top, are consistently unable to arrange them into any coherent pattern; as though that simple rectangle were unable to serve in their case as a homogeneous and neutral space in which things could be placed so as to display at the same time the continuous order of their identities or differences as well as the semantic field of their denomination. Within this simple space in which things are normally arranged and given names, the aphasiac will create a multiplicity of tiny, fragmented regions in which nameless resemblances agglutinate things into unconnected islets; in one corner, they will place the lightest-coloured skeins, in another the red ones, somewhere else those that are softest in texture, in yet another place the longest, or those that have a tinge of purple or those that have been wound up into a ball. But no sooner have they been adumbrated than all these groupings dissolve again, for the field of identity that sustains them, however limited it may be, is still too wide not to be unstable; and so the sick mind continues to infinity, creating groups then dispersing them again, heaping up diverse similarities, destroying those that seem clearest, splitting up things that are identical, superimposing different criteria, frenziedly beginning all over again, becoming more and more disturbed, and teetering finally on the brink of anxiety.
THE ORDER OF THINGS: An Archaeology of the Human Sciences, MICHEL FOUCAULT, A translation of Les Mots et les choses, VINTAGE BOOKS, A Division of Random House, Inc., New York, Preface
Taxonomy is the intersection of words and things — and just this was the original title of Foucault’s book, i.e., words and things — and Foucault brilliantly illustrates both the possibilities and problems inherent in taxonomy. Foucault had an enduring concern for taxonomy, and, as is well known, named his chair at the Collège de France the “History of Systems of Thought” — as though he were seeking a master taxonomy of human knowledge.
Foucault found madness and mental illness in the inability of a test subject to systematically arrange skeins of wool, since each attempted scheme of classification breaks down when it overlaps within another system of classification pursued simultaneously. One suspects that if the task placed before Foucault’s aphasiac were limited in certain ways — perhaps in the number of colors of wool, or the number of categories that could be employed — the task might become practical once a sufficient number of constraints come into play. But the infinite universe investigated by contemporary science is the very antithesis of constraint. There is always more to investigate, and as the sciences themselves grow and fission, begetting new sciences, the task of bringing order to the sciences themselves (rather than to the empirical phenomena that the sciences seek to order) becomes progressively more difficult.
The taxonomy of the sciences is more problematic that usually recognized. Consider these possible categories of science, not all of which are current today:
● natural sciences It is still somewhat common to speak of the “natural sciences,” with our intuitive understanding of what is “natural” as sufficient to classify a given study as an investigation into “nature.” What, then, is not a natural science? At one time there was a strong distinction made between the natural sciences and the formal sciences (q.v.)
● formal sciences The phrase “formal sciences” is rarely used today, though it is still a useful idea, comprising at least mathematics and logic and (for those who know what it is) formal mereology. Today the formal sciences might also include computer science and information science, though I haven’t myself ever heard anyone refer to these sciences as formal sciences. Since the mathematization of the natural sciences beginning with the scientific revolution, the natural sciences have come more and more to approximate formal sciences, to the point that mathematical physics has, at times, only a tenuous relationship to experiments in physics, while it has a much more robust relationship with mathematics.
● moral sciences Philosopher J. R. Lucas has written of the moral sciences, “The University of Cambridge used to have a Faculty of Moral Sciences. It was originally set up in contrast to the Faculty of Natural Sciences, and was concerned with the mores of men rather than the phenomena of nature. But the humane disciplines were hived off to become separate subjects, and when the faculty was finally renamed the Faculty of Philosophy, philosophy was indeed the only subject studied.”
● earth sciences The earth sciences may be understood to be a subdivision of the natural sciences, and may be strongly distinguished from the space sciences, but the distinction between the earth sciences and the space sciences, as well as these two sciences themselves, is quite recent, dating to the advent of the Space Age in the middle of the twentieth century. While the idea behind the earth sciences is ancient, their explicit recognition as a special division within the sciences is recent. I suspect that the fact of seeing the earth from space, made possible by the technology of the space age, contributed greatly to understanding the earth as a unified object of investigation.
● space sciences The space sciences can be defined in contradistinction to the earth sciences, as though science had a need to recapitulate the distinction between the sublunary and the superlunary of Ptolemaic cosmology; however, I don’t think that this was the actual genesis of the idea of a category of space sciences. The emergence of the “Space Age” and its associated specialty technologies, and the sciences that produced these technologies, is the likely source, but the question becomes whether a haphazardly introduced concept roughly corresponding to a practical division of scientific labor constitutes a useful theoretical category.
● social sciences The social sciences would obviously include sociology and cultural anthropology, but would it include biological anthropology? History? Political science? Economics? The social sciences often come under assault for their methodology, which seems to be much less intrinsically quantitative than that of the natural sciences, but are not social communities as “natural” as biologically defined communities?
● human sciences In German there is a term — Geisteswissenschaften — that could be translated as the “spiritual sciences,” and which roughly corresponds to the traditional humanities, but it is not entirely clear whether the human sciences coincide perfectly either with Geisteswissenschaften or the humanities. Foucault’s The Order of Things, quoted above, is subtitled, “An Archaeology of the Human Sciences,” and the human sciences that Foucault examines in particular include philology and economics, inter alia.
● life sciences I assume that “life sciences” was formulated as a collective term for biological sciences, which would include studies like biogeography, which might also be called an instance of the earth sciences, or the natural sciences. But the life sciences would also include all of medicine, which gives us a taxonomy of the medical sciences, though it does not give us a clear demarcation between the life sciences and the natural sciences. Does medicine include all of psychiatry, or ought psychiatric inquiries to be thought of as belonging to the social sciences?
● historical sciences I have written about the historical sciences in several posts, since S. J. Gould often made the point that that historical sciences have a distinctive methodology. In Historical Sciences I argued that there is a sense in which all sciences can be considered historical sciences. Indeed, one of the distinctive aspects of the scientific revolution has been to force human beings to stop assuming the eternity and permanence of the world and to see the world and everything in it as having a natural history. If everything has a natural history, then all investigations are historical investigations and all sciences are historical sciences — but if this is true, then Gould’s claim that the historical sciences have a unique methodology collapses.
There are also, of course, informal distinctions such as that between the “hard” sciences and the “soft” sciences, which is sometimes taken to be the distinction between mathematicized sciences and non-mathematicized sciences, and so may correspond to the rough distinction between the natural sciences and the social sciences, except the that the social sciences are now dominated by statistical methods and can no longer be thought of a non-mathematicized. This leads to problems of classification such as whether economics, for example, is a natural science or a social science.
For each of the science categories above we could attempt either an extensional or an intensional definition, i.e., we could give a list of particular sciences that fall under the category in question, or we could attempt to define the meaning of the term, and the meaning would then govern what sciences are so identified. An extensional definition of the earth sciences might involve a list including geomorphology, biogeography, geology, oceanography, hydrology, climatology, and so forth. An intentional definition of the earth sciences might be something like, “those sciences that have as their object of study the planet earth, its subsystems, and its inhabitants.”
Today we employ the sciences to bring order to our world, but how do we bring order to the sciences? Ordering our scientific knowledge is problematic. It is complicated. It involves unanticipated difficulties that appear when we try to make any taxonomy for the sciences systematic. Each of the scientific categories above (as well as others that I did not include — my list makes no pretension of completeness) implies a principled distinction between the kind of sciences identified by the category and all other sciences, even if the principle by which the distinction is to be made is not entirely clear.
The implicit distinction between the earth sciences and the space sciences has a certain intuitive plausibility, and it is useful to a certain extent, though recently I have tried to point out in Eo-, Exo-, Astro- the importance of astrobiology as unifying terrestrial biology and exobiology in a truly Copernican framework. While the attempted task of a taxonomy of the sciences is important, the nature of the task itself suggests a certain compartmentalization, and too much thinking in terms of compartmentalization can distract us from seeing the larger synthesis. Concepts based on categorization that separates the sciences will be intrinsically different from extended conceptions that emerge from unification. An exclusive concern for the earth sciences, then, might have the subtle affect of reinforcing geocentric, Ptolemaic assumptions, though if we pause for a moment it will be obvious that the earth is a planet, and that the planetary sciences ought to include the earth, and the the planetary sciences might be construed as belonging to the space sciences.
The anxiety experience by Foucault’s aphasiac is likely to be experienced by anyone attempting a systematic taxonomy of the sciences, as here, any mind, whether sick or healthy, might continue to extrapolate distinctions to infinity and still not arrive at a satisfactory method for taking the measure of the sciences in way that contributes both to the clarity of the individual sciences and an understanding of how the various special sciences relate to each other.
On the one hand, perfect rigor of thought would seem to imply that all possible distinctions must be observed and respected, except that not all distinction can be made at the same time because some cut across each other, are mutually exclusive, order the world differently, and subdivide other categories and hierarchies in incompatible schemes. To use a Leibnizean term, not all distinctions are compossible.
To invoke Leibniz in this context is to suggest a Leibnizean approach to the resolution of the difficulty: a Leibnizean conception of conceptual rigor would appeal to the greatest number of distinctions that are compossible and yield a coherent body of knowledge.
A thorough-going taxonomic study of human bodies of knowledge would reveal a great many possible taxonomies, some with overlapping distinctions, but it is likely that there is an optimal arrangement of distinctions that would allow the greatest possible number of distinctions to be employed simultaneously while retaining the unity of knowledge. This would be a system of compossible taxonomy, which might have to reject a few distinctions but which makes use of the greater number of distinctions that are mutually possible within the framework of methodological naturalism as this defines the scientific enterprise.
There are not merely academic considerations. The place of science within industrial-technological civilization means that our conception of science is integral with our conception of civilization; thus to make a systematic taxonomy of the sciences is to make a systematic taxonomy of a civilization that is based upon science. Such conception categories extrapolated from science to civilization will have consequences for human self-understanding and human interaction, which latter does not always take the form of “cultural exchanges” (in the saccharine terminology if international relations). Industrial-technological civilization is in coevolution with industrial-technological warfare, so that a taxonomy of science is also a taxonomy of scientific warfare. Our conception of science will ultimately influence how we kill each other, and how we seek peace in order to stop killing each other.
One of the most distinctive forms of propaganda and social engineering of our time is the creation from whole cloth of artificial and fraudulent sciences. Since science is the condition of legitimacy in industrial-technological civilization, social movements seeking legitimacy seek scientific justification for their moral positions, but the more that science is seen as a means to an end, where the end is stipulated in advance, then science as a process must be compromised because any science that does not tend to the desired socio-political end will be subject to socio-political disapproval or dismissal. While there is a limit to this, the limits are more tolerant than we might suppose: large, complex societies with large and diverse economies can sustain non-survival behavior for a significant period of time — perhaps enough time to conceal the failure of the model employed until it is too late to save the society that has become a victim of its own illusion.
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