Sacrificing Natural Kinds

The Kripkean conception of natural kinds (kinds are defined by essences that are intrinsic to their members and that lie at the microphysical level) indirectly finds support in a certain conception of a law of nature, according to which generalizations must have unlimited scope and be exceptionless to count as laws of nature. On my view, the kinds that constitute the subject matter of special sciences such as biology may very well turn out to be natural despite the fact that their essences fail to be microphysical or micro-based. On the causal conception of natural kinds I privilege, the naturalness of a kind is a function of the fact that it figures prominently in at least one causal law. However, there is a strong tendency prevailing among contemporary philosophers to assume that, in order to count as proper laws generalizations must be expectionless. Since most generalizations tracked down by the special sciences turn out not to fulfill these criteria, what this conception of a law implies is that most of the generalizations the special sciences trade in are not proper laws. It follows that, on this view, most if not all of the kinds the special sciences dealing with turn out not to constitute natural kinds, understood as kinds to which bona fide laws apply. In order to establish that the non-microstructurally defined kinds that fall within the domain of enquiry of the special sciences are eligible for the status of natural kind, I must therefore establish that generalizations needn’t have unlimited scope and be exceptionless to count as laws of nature. This is precisely what I seek to do in this paper. I begin by arguing that the question “what is a law of nature?” is most naturally interpreted as the question “what features must generalizations exhibit in order to ground scientific explanations?” and by offering reasons to believe that generalizations needn’t be exceptionless and have unlimited scope to play the crucial role laws have been thought to play in scientific explanation. Drawing on Sandra Mitchell [Mitchell, S. (2000). Philosophy of Science, 67, 242–265] and James Woodward’s [Woodward, J. (1997). Philosophy of science, 64 (proceedings), 524–541; Woodward, J. (2000). British Journal for the philosophy of science, 51(2), 197–254; Woodward, J. (2001). Philosophy of science, 68, 1–20] work, I subsequently develop an alternative account of the criteria generalizations must satisfy in order to count as laws of nature, which at least some of the generalizations of the special sciences turn out to fulfill. I thus give credence to the idea that at least some of the kinds that fall within the domain of the special sciences figure in laws of nature, and I thereby restore the possibility that some special science kinds deserve to be deemed natural.

Jerry Fodor has argued that the multiple realizability argument, as discussed in his original “Special Sciences” article, “refutes psychophysical reductionism once and for all.” I argue that his argument in “Special Sciences” does no such thing. Furthermore, if one endorses the physicalism that most supporters of the “Special Sciences” view endorse, special science laws must be reducible, in principle. The compatibility of MR with reduction, however, need not threaten the autonomy of the special sciences.

Special Sciences: still a flawed argument after all these years

<i>Metaphysical Emergence</i>

Laws in the special sciences are usually regarded to be non-universal. A theory of laws in the special sciences faces two challenges. (I) According to Lange's dilemma, laws in the special sciences are either false or trivially true. (II) They have to meet the ‘requirement of relevance’, which is a way to require the non-accidentality of special science laws. I argue that both challenges can be met if one distinguishes four dimensions of (non-) universality. The upshot is that I argue for the following explication of special science laws: L is a special science law just if (1) L is a system law, (2) L is quasi-Newtonian, and (3) L is minimally invariant.

Perhaps there have been at least as many attempts to answer philosophical questions by means of an approach belonging to one or another special science as there have been attempts by philosophy to defend her right to an authentically philosophical approach. Questions about the nature of man and his world, culture, are especially at stake. However, the matter of reductionism does not just play a role in the relation between the special sciences and philosophy: within the special sciences themselves too there has been much resistance to the urge for expansion of certain approaches to the detriment of others (this holds outside science too: one can think of the resistance the anti-globalization movement offers to ‘neo-liberalism’).

One of the main early forms of functionalism, developed by writers like Jerry Fodor and William Lycan, focused on explanation in the special sciences and argued that in psychology were continuous in nature with the special science properties posited in such mechanistic explanations. I dub the latter positionContinuity and use it to critically examine the of the metaphysics of functionalism which takes functional properties to be second-order properties and claims there are two metaphysical forms of functionalism, in so-called role and realizer functionalism. Looking at mechanistic explanations, I show that the posited in the special sciences are not second-order properties and that Continuity Functionalism is a distinctive metaphysical version of functionalism not covered by the Standard Picture. My conclusion is that the Standard Picture offers us a false dichotomy of ways to be a functionalist and that functionalists thus need to look once more to the special sciences to configure their views, thus eschewing the machinery inherited from analytic philosophers.

An important obstacle to lawhood in the special sciences is the worry that such laws would require metaphysically extravagant conspiracies among fundamental particles. How, short of conspiracy, is this possible? In this paper we’ll review a number of strategies that allow for the projectibility of special science generalizations without positing outlandish conspiracies: non-Humean pluralism, classical MRL theories of laws, and Albert and Loewer’s theory. After arguing that none of the above fully succeed, we consider the conspiracy problem through the lens of our preferred view of laws, an elaboration of the MRL view that we call the Better Best System (BBS) theory. BBS offers a picture on which, although all events supervene on a fundamental level, there is no one unique locus of projectibility; rather there are a large number of loci corresponding to the different areas (ecology, economics, solid-state chemistry, etc.) in which there are simple and strong generalizations to be made. While we expect that some amount of conspiracy-fear-inducing special science projectibility is inevitable given BBS, we’ll argue that this is unobjectionable. It follows from BBS that the laws of any particular special or fundamental science amount to a proper subset of the laws. From this vantage point, the existence of projectible special science generalizations not guaranteed by the fundamental laws is not an occasion for conspiracy fantasies, but a predictable fact of life in a complex world.

Naturalists take science at face value and hence ought to be ontologically committed to the entities posited by the various special sciences. According to the Eleatic principle, causal efficacy is necessary condition for existence. This principle is plausible for concrete entities and so naturalists must attribute genuine causal powers to special science ontologies. However, physicalism is usually taken to require a commitment to the causal completeness of the physical world, and so a generalization of Kim's causal exclusion argument threatens the special sciences with the dilemma of epiphenomenalism versus reductionism. The former is incompatible with the Eleatic principle and so motivates eliminativism about the ontologies of the special sciences, whereas the latter is widely held to be untenable. Hence, there is a tension between physicalism and naturalism. However, ironically among philosophers of physics there is a widespread view that there is no causation in fundamental physics, suggesting the physicalism must be understood without reference to causal completeness. In this paper I argue that a weak form of physicalism can be combined with an independently motivated account of special science ontology to dissolve the generalized causal exclusion problem and harmonise naturalism and physicalism.

In Defence of “Emotion”

In this paper, I investigate how different views about the vertical and horizontal structure of reality affect the debate between reductive and non-reductive physicalism. This debate is commonly assumed to hinge on whether there are high-level, special science properties that are distinct from low-level physical properties and whether the alleged multiple realizability of highlevel properties establishes this. I defend a metaphysical interpretation of non-reductive physicalism in the absence of both of these assumptions. Adopting an independently motivated, discipline-relative account of natural properties and appealing to a phenomenon I call “multiple determinativity,” in which a single physical property simultaneously realizes different kinds of special science properties, is sufficient to show that some special science properties are irreducible to physical properties and that non-reductive physicalism is not merely a terminological variant of reductive physicalism. For roughly the past forty years, discussions of reductive and non-reductive physicalism have centered on a number of related debates, including the nature and extent of multiple realizability (MR) and whether the MR of a property grounds its irreducibility (e.g., Putnam 1967; Lewis [1969] 1980; Fodor 1974; Kim 1998; Shapiro 2000; Gillett 2003). These debates have commonly been articulated against the background assumption that there is a “vertical” structure of reality. For instance, Jaegwon Kim writes: For much of [the 20th] century, a layered picture of the world . . . has formed a constant—tacitly assumed if not explicitly stated—backdrop for debates on a variety of issues in metaphysics and philosophy of science—for example, reduction and reductionism, the mind-body problem, emergence, the status of the special sciences, and the possibility of a unified science. (1998, 16) As Kim also notes, “sometimes the layered model is couched in terms of concepts and languages rather than entities and their properties” (ibid.). Indeed, some philosophers have voiced skepticism about the existence of metaphysical levels in nature. They argue that levels

This paper concerns what Jerry Fodor calls a metaphysical mystery': How can there be macroregularities that are realized by wildly heterogeneous lower level mechanisms? But the answer to this question is not as mysterious as many, including Jaegwon Kim, Ned Block, and Jerry Fodor might think. The multiple realizability of the properties of the special sciences such as psychology is best understood as a kind of universality, where 'universality' is used in the technical sense one finds in the physics literature. It is argued that the same explanatory strategy used by physicists to provide understanding of universal behavior in physics can be used to explain how special science properties can be heterogeneously multiply realized. 1 Introduction 2 Jade, pain, microstructure and causal powers 3 Universality 4 Explaining universality 5 The general explanatory strategy 6 Special sciences 7 An objection and a reply 8 Conclusion 9 Appendix: qualitative features of a renormalization group analysis.

It appears to us that things in the natural world divide into different kinds. The most obvious examples come from biology. Cats are clearly distinct from mice; while both kinds show variation, all the cats are more similar to one another than they are to any mouse. We see different kinds of tree and different kinds of lichen. These are kinds that are apparent to any reasonably careful observer. Other kinds seem to be revealed by science. The chemical revolution gave us new ideas about what it is to be a chemical element, and in the subsequent decades many dozens of these different basic chemical kinds were revealed. The following century uncovered a multiplicity of different kinds of fundamental physical particle. While at a different set of scales, geologists distinguish different kinds of rock, meteorologists distinguish different kinds of weather system, and astronomers distinguish different kinds of galaxy. The philosophical questions that natural kinds generate can themselves be categorized into three types as they relate to metaphysics, philosophy of language, and philosophy of science. (It should be noted nonetheless that discussion of these questions quite rightly overlaps these fields. Consequently, works listed in this article may be relevant to further sections in addition to the ones they are listed under.) Here are examples of the philosophical questions surrounding natural kinds. Does the world itself genuinely have a structure of objective natural kinds, so that there are natural divisions of things by kinds? And do our actual natural classifications match those kinds? Or are what we take to be kinds merely the product of a particular non-objective perspective? How does a natural kind (or belonging to a natural kind) differ from other natural properties? In virtue of what do things group themselves into kinds? How is kind membership determined—for example, by necessary and sufficient conditions or by something else? Do, indeed, natural kinds have essences? Are there entities that are the natural kinds? Do our natural kind terms refer to such entities rather as names refer to objects? Is there a non-trivial way of spelling out the idea of rigid designation for natural kinds terms? Do the semantics of natural kind terms vindicate essentialism about kinds? Does what we discover about kinds in the special sciences (e.g., concerning chemical substances and biological species) support or undermine philosophical conceptions of kinds?

Philosophers of the special sciences seem to find it important to ask whether or not particular groupings of things that feature in particular special sciences can be conceived of as natural kinds.1 For example, a quick search of the philosophical literature of the past decades comes up with several dozens of papers targeting the question “Is … a natural kind?”, many of these concerning kinds of emotions and the emotion category in psychology2 and the category of concepts in psychology / cognitive science.3

This article is an introduction to the Synthese Special Issue, Natural Kinds: Language, Science, and Metaphysics. The issue includes new contributions to some of the main questions involved in the present philosophical debates on natural kinds and on natural kind terms. Those debates are relevant to philosophy of language, philosophy of science, and metaphysics. In philosophy of language it is highly debated what the meaning of natural kind terms is, how their reference is determined, as well as whether there are differences and similarities between the semantics of natural kind terms and that of other sorts of kind terms. In philosophy of science, natural kinds are relevant because they are the basis for scientific classifications and play an explanatory role in scientific theories; thus one aim of science is to discover natural kinds and theorize about them. Natural kinds are also relevant in metaphysics, where many questions involving natural kinds are debated and especially those concerning the sort of entities we refer to when using natural kind terms, i.e., the ontological status of natural kinds; in this regard there are different views, such as conventionalism, realism and essentialism. Another metaphysical question is what it is that characterizes the naturalness of kind divisions. The introduction sketches the antecedents of some of the present views on natural kinds and natural kind terms, and indicates some of the topics dealt with in the articles that make up the issue, which can be classified in the following groups: (1) the metaphysics and epistemology of natural kinds (2) the semantics of natural kind terms and other kind terms (3) questions on species and (4) other related issues on natural kinds. However, many of the articles cover more than just one of these topics.