Matthew Slater

In this paper, I consider ways of responding to critiques of natural kinds monism recently suggested from the pluralist camp. Even if monism is determined to be untenable in certain domains (say, about species), it might well be tenable in others. Chemistry is suggested to be such a monist‐friendly domain. Suggestions of trouble for chemical kinds can be defused by attending to the difference between monism as a metaphysical thesis and as a claim about classification systems. Finally, I consider enantiomers as a test case for the monism/pluralism debate. The question of whether enantiomers differ in kind does not appear easily answerable. I suggest that this legislates for pluralism in chemistry.

What are species? Are they objective features of the world? If so, what sort of features are they? Do everyday intuitions that species are real stand up to philosophical and scientific scrutiny? Two rival accounts of species' reality have dominated the discussion: that species are natural kinds defined by essential properties and that species are individuals. Unfortunately, neither account fully accommodates biological practice. In Are Species Real?, Slater presents a novel approach to this question aimed at accommodating the attractions to both realism and antirealism about species.

Do the laws of nature supervene on ordinary, non-nomic matters of fact? Lange's criticism of Humean supervenience (HS) plays a key role in his account of natural laws. Though we are sympathetic to his account, we remain unconvinced by his criticism. We focus on his thought experiment involving a world containing nothing but a lone proton and argue that it does not cast sufficient doubt on HS. In addition, we express some concern about locating the lawmakers in an ontology of primitive subjunctive facts and suggest that a 'mixed' metaphysics to the lawmaker question might be attractive

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..

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.