Philosophers have long been interested in a series of interrelated questions about natural kinds. What are they? What role do they play in science and metaphysics? How do they contribute to our epistemic projects? What categories count as natural kinds? And so on. Owing, perhaps, to different starting points and emphases, we now have at hand a variety of conceptions of natural kinds—some apparently better suited than others to accommodate a particular sort of inquiry. Even if coherent, this situation isn’t (...) ideal. My goal in this article is to begin to articulate a more general account of ‘natural kind phenomena’. While I do not claim that this account should satisfy everyone—it is built around a certain conception of the epistemic role of kinds and has an obvious pragmatic flavour—I believe that it has the resources to go further than extant alternatives, in particular the homeostatic property cluster view of kinds. (shrink)

Different chemical species are often cited as paradigm examples of structurally delimited natural kinds. While classificatory monism may thus seem plausible for simple molecules, it looks less attractive for complex biological macromolecules. I focus on the case of proteins that are most plausibly individuated by their functions. Is there a single, objective count of proteins? I argue that the vagaries of function individuation infect protein classification. We should be pluralists about macromolecular classification.

Good chefs know the importance of maintaining sharp knives in the kitchen. What’s their secret? A well-worn Taoist allegory offers some advice. The king asks about his butcher’s impressive knifework. “Ordinary butchers,” he replied “hack their way through the animal. Thus their knife always needs sharpening. My father taught me the Taoist way. I merely lay the knife by the natural openings and let it find its own way through. Thus it never needs sharpening” (Kahn 1995, vii; see also Watson (...) 2003, 46). Plato famously employed this image as an analogy for the reality of his Forms (Phaedrus, 265e). Just like an animal, the world comes pre-divided for us. Ideally, our best theories will be those which “carve nature at its joints”. While Plato employed the “carving” metaphor to convey his views about the reality of his celebrated Forms, its most common contemporary use involves the success of science -- particularly, its success in identifying distinct kinds of things. Scientists often report discovering new kinds of things -- a new species of mammal or novel kind of fundamental particle, for example -- or uncovering more information about already familiar kinds. Moreover, we often notice considerable overlap in different approaches to classification. As Ernst Mayr put it: No naturalist would question the reality of the species he may find in his garden, whether it is a catbird, chickadee, robin, or starling. And the same is true for trees or flowering plants. Species at a given locality are almost invariably separated from each other by a distinct gap. Nothing convinced me so fully of the reality of species as the observation . . . that the Stone Age natives in the mountains of New Guinea recognize as species exactly the same entities of nature as a western scientist. (Mayr 1987, 146) Such agreement is certainly suggestive. It suggests that taxonomies are discoveries rather than mere inventions. Couple this with their utility in scientific inference and explanation and we have compelling reason for accepting the objective, independent reality of many different natural kinds of things.. (shrink)

RÉSUMÉJe soulève des questions concernant l'approche volontariste défendue par Chakravartty à l’égard des positions : supposant que nous reconnaissons une hiérarchie des positions, la position volontariste peut être à la fois vraie et trompeuse en ce qui concerne la viabilité pratique de certains débats dans le domaine de la philosophie des sciences, en particulier le débat sur le réalisme scientifique ou sur la façon de «naturaliser» la métaphysique.

Talk of different types of cells is commonplace in the biological sciences. We know a great deal, for example, about human muscle cells by studying the same type of cells in mice. Information about cell type is apparently largely projectible across species boundaries. But what defines cell type? Do cells come pre-packaged into different natural kinds? Philosophical attention to these questions has been extremely limited [see e.g., Wilson (Species: New Interdisciplinary Essays, pp 187–207, 1999; Genes and the Agents of Life, (...) 2005; Wilson et al. Philos Top 35(1/2):189–215, 2007)]. On the face of it, the problems we face in individuating cellular kinds resemble those biologists and philosophers of biology encountered in thinking about species: there are apparently many different (and interconnected) bases on which we might legitimately classify cells. We could, for example, focus on their developmental history (a sort of analogue to a species’ evolutionary history); or we might divide on the basis of certain structural features, functional role, location within larger systems, and so on. In this paper, I sketch an approach to cellular kinds inspired by Boyd’s Homeostatic Property Cluster Theory, applying some lessons from this application back to general questions about the nature of natural kinds. (shrink)

Stars are conspicuously absent from reflections on natural kinds and scientific classifications, with gold, tiger, jade, and water getting all the philosophical attention. This is too bad for, as this paper will demonstrate, interesting philosophical lessons can be drawn from stellar taxonomy as regards two central, on-going debates about natural kinds, to wit, the monism/pluralism debate and the realism/antirealism debate. I’ll show in particular that stellar kinds will not please the essentialist monist, nor for that matter will it please the (...) pluralist embracing promiscuous realism à la Dupré. (shrink)

I reconsider the monism/pluralism debate about natural kinds. Monism claims that there is a privileged division of reality into natural kinds, while pluralism states that there are many ways of classifying objects according to different purposes. I compare three different monistic accounts of natural kinds with the pluralism advocated by promiscuous realism. The analysis of some examples of the classification of celestial objects suggest that there are indeed different legitimate ways of classifying things according to different purposes; contrary to monism, (...) the boundaries between kinds are not fixed. These results show that promiscuous realism is a better account of natural kind. (shrink)

In this paper I explore Aristotle’s views on natural kinds and the compatibility of pluralism and realism, a topic that has generated considerable interest among contemporary philosophers. I argue that, when it came to zoology, Aristotle denied that there is only one way of organizing the diversity of the living world into natural kinds that will yield a single, unified system of classification. Instead, living things can be grouped and regrouped into various cross-cutting kinds on the basis of objective similarities (...) and differences in ways that subserve the explanatory context. Since the explanatory aims of zoology are diverse and variegated, the kinds it recognizes must be equally diverse and variegated. At the same time, there are certain constraints on which kinds can be selected. And those constraints derive more from the causal structure of the world than from the proclivities of the classifier (hence the realism). This distinguishes Aristotle’s version of pluralistic realism from those contemporary versions (like Dupré’s “promiscuous realism”) that treat all or most classifications of a given domain as equally legitimate and not just a sub-set of kinds recognized by the science that studies it. By contrast, Aristotle privileges scientifically important kinds on the basis of their role in causal investigations. On this picture natural kinds are those kinds with the sort of causal structure that allows them to enter into scientific explanations. In the final section I argue that Aristotle’s zoology should remain of interest to philosophers and biologists alike insofar as it combines a pluralistic form of realism with a rank-free approach to classification. (shrink)

There is a perennial philosophical dream of a certain natural order for the natural kinds. The name of this dream is ‘the hierarchy requirement’. According to this postulate, proper natural kinds form a taxonomy which is both unique and traditional. Here I demonstrate that complex scientific objects exist: objects which generate different systems of scientific classification, produce myriad legitimate alternatives amongst the nonetheless still natural kinds, and make the hierarchical dream impossible to realize, except at absurdly great cost. Philosophical hopes (...) for a certain order in nature cannot be fulfilled. Natural kinds crosscut one another, ubiquitously so, and this crosscutting spells the end of the hierarchical dream. (shrink)

Scientific realism has three dimensions: a metaphysical commitment to the existence of a mind-independent world; a semantic commitment to a literal interpretation of scientific claims; and an epistemological commitment to scientific knowledge of both observable and unobservable entities. The semantic dimension is uncontroversial, and the epistemological dimension, though contested, is well articulated in a number of ways. The metaphysical dimension, however, is not even well articulated. In this paper, I elaborate a plausible understanding of mind independence for the realist – (...) plausible in conceding the force of sceptical arguments to the effect that there is no one correct way to carve nature at its joints, but realist in proposing an objective basis for carving nonetheless. Walking this line between implausible realism and full-blown constructivism leads down the path of three forms of relativism or pluralism: one concerning the ways in which scientists “package” properties into entities; another concerning the precise metaphysical natures of these entities; and another concerning the context relativity of their behaviour. (shrink)

Conceptual change can occur for a variety of reasons; some more scientifically significant than others. The 2006 definition of ‘planet’, which saw Pluto reclassified as a dwarf planet, is an example toward the more mundane end of the scale. I argue however that this case serves as a useful example of a related phenomenon, whereby what appears to be a single kind term conceals two or more distinct concepts with independent scientific utility. I examine the historical background to this case, (...) as a template for developing additional evidence for pluralist approaches to conceptual disputes within science and elsewhere. (shrink)

Richard Boyd has long campaigned for a view of natural kinds he calls the Homeostatic Property Cluster account. This account has been particularly exciting for philosophers of biology unhappy with traditional essentialism about natural kinds and the views that biological kinds are, in one way or another, “historical entities”. Though defenders of HPC kinds have done much to further articulate the view, many questions about the account remain. One pressing question concerns the way in which HPC kinds are supposed to (...) accommodate our inductive and explanatory practices via causal, homeostatic mechanisms. In addressing the question, I am led to an alternative conception of what a property cluster kind might be. I call my alternative, in deference to its Boydian origins, the Stable Property Cluster account of natural kinds. Rather than emphasizing homeostasis or causal mechanism, the SPC account emphasizes the stability of a property cluster over the various ways stability may be maintained. In virtue of this modest change of emphasis, the SPC account does not advertise itself as an account of a kind of natural kind — it is, I think, an attractive candidate for a general natural kind concept, able to accommodate the diversity of natural kinds we find in the world. (shrink)