This paper defends an ontology of weak entity realism for homeostatic property cluster (HPC) theories of natural kinds, adapted from Bird’s (Synthese 195(4):1397–1426, 2018) taxonomy of such theories. Weak entity realism about HPC kinds accepts the existence of natural kinds. Weak entity realism denies two theses: that (1) HPC kinds have mind-independent essences, and that (2) HPC kinds reduce to entities, such as complex universals, posited only by metaphysical theories. Strong entity realism accepts (1) and (2), whereas moderate entity realism (...) accepts only (1). Given its commitment to (2), strong entity realism is more theoretically complex than weak entity realism, with little explanatory payoff. Given their commitment to (1), moderate and strong entity realisms cannot explain how the identity conditions of HPC kinds are to be straightforwardly knowable. I argue that weak entity realism avoids such epistemic difficulties. I further rebut two plausible criticisms of weak entity realism, namely that weak entity realism cannot account for quantification over kinds, and that weak entity realism cannot provide identity conditions for HPC kinds which are both scientifically useful and objective. Given the theoretical costs of strong and moderate entity realism, and weak entity realism’s adequate response to its most plausible challenges, weak entity realism about HPCs is to be preferred, especially for biological and chemical kinds. (shrink)

The epistemology of essence is a topic that has received relatively little attention, although there are signs that this is changing. The lack of literature engaging directly with the topic is probably partly due to the mystery surrounding the notion of essence itself, and partly due to the sheer difficulty of developing a plausible epistemology. The need for such an account is clear especially for those, like E.J. Lowe, who are committed to a broadly Aristotelian conception of essence, whereby essence (...) plays an important theoretical role. In this chapter, our epistemic access to essence is examined in terms of the a posteriori vs. a priori distinction. The two main accounts to be contrasted are those of David S. Oderberg and E.J. Lowe. (shrink)

In this chapter, it is suggested that our epistemic access to metaphysical modality generally involves rationalist, a priori elements. However, these a priori elements are much more subtle than ‘traditional’ modal rationalism assumes. In fact, some might even question the ‘apriority’ of these elements, but I should stress that I consider a priori and a posteriori elements especially in our modal inquiry to be so deeply intertwined that it is not easy to tell them apart. Supposed metaphysically necessary identity statements (...) involving natural kind terms are a good example: the fact that empirical input is crucial in establishing their necessity has clouded the role and content of the a priori input, as I have previously argued. For instance, the supposed metaphysically necessary identity statement involving water and its microstructure can only be established with the help of a controversial a priori principle concerning the determination of chemical properties by microstructure. The Kripke-Putnam framework of modal epistemology fails precisely because it is unclear whether the required a priori element is present. My positive proposal builds on E. J. Lowe’s work. Lowe holds that our knowledge of metaphysical modality is based on our knowledge of essence. Lowe’s account strives to offer a uniform picture of modal epistemology: essence is the basis of all our modal knowledge. This is the basis of Lowe’s modal rationalism. I believe that Lowe’s proposal is on the right lines in the case of abstract objects, but I doubt that it can be successfully applied to the case of natural kinds. Accordingly, the case of natural kinds will be my main focus and I will suggest that modal rationalism, at least as it is traditionally understood, falls short of explaining modal knowledge concerning natural kinds. Yet, I think that Lowe has identified something of crucial importance for modal epistemology, namely the essentialist, a priori elements present in our modal inquiry. The upshot is that rather than moving all the way from modal rationalism to modal empiricism, a type of hybrid approach, ‘empirically-informed modal rationalism ’, can be developed. (shrink)

In this paper I raise a difficulty for Joseph LaPorte's account of chemical kind terms. LaPorte has argued against Putnam that H₂O content is neither necessary nor sufficient to fix the reference of the kind term 'water' and that we did not discover that water is H₂O. To this purpose, he revisits Putnam's Twin Earth story with the fictional scenario of Deuterium Earth, whose ocean consists of 'dwater', to conclude that we did not discover that deuterium oxide is (a kind (...) of) water (usually called 'heavy water'). Instead, according to LaPorte, by including deuterium oxide in the extension of the term 'water', we simply refined our vague use of the term 'water'. But we could have decided to exclude deuterium oxide from the extension of the term 'water'. Let us call this the thesis of semantic stipulation. I raise two problems for LaPorte's Deuterium Earth story. First, I show that 'dwater' (i.e. deuterium oxide not as a kind of water) does not have the same scientific credibility of 'heavy water' (i.e. deuterium oxide as a kind of water). Second, I argue that for the thesis of semantic stipulation to go through one would need to show that 'dwater' is semantically on a par with 'heavy water'. Namely, one would need to show that 'dwater' is a projectible kind term, capable of supporting inductive inferences. But, in fact, it is not, because the term is vulnerable to an unwelcome Goodmanian scenario, unless one surreptitiously reintroduces some Putnamian assumptions about D₂O content being necessary and sufficient to fix the reference of the term. (shrink)

El objetivo del presente trabajo es, por un lado, reivindicar la importancia e influencia del enfoque de Locke para la discusión sobre los géneros naturales y, por otro, mostrar cómo su visión y aportaciones en torno al sistema de clasificación natural resultan de gran utilidad para entender en profundidad la compleja geografía del debate contemporáneo sobre estos géneros. En particular, ofrecemos una interpretación según la cual las concepciones de género natural se comprenden como críticas realistas a la posición que sostiene (...) Locke y mostramos cómo una importante tensión que aflora en la propuesta de Locke reaparece en el actual debate sobre los géneros naturales. (shrink)

We need to distinguish two sorts of natural kinds, scientific and common NKs, because the notion of NK, which has to satisfy demands at three different levels—ontological, semantic and epistemological—, is subject to two incompatible sets of constraints. In order to prove this, I focus on the much-discussed case of jade. In the first part of the paper, I show that the current accounts are unsatisfactory because they are inconsistent. In the process, I explain why LaPorte’s analysis of “jade” as (...) a vernacular NK-term with an open-texture meaning does not offer a way out. Using a reductio ad absurdum argument, I conclude that according to the main tenets of NK-term theories, today’s “jade” has to be an NK-term, and jade thereby an NK. In the second part of the paper, I argue for this conclusion in a positive manner. First, I present a series of thought experiments demonstrating that today’s “jade” has the specific features of an NK-term. Then, I show that the kind that we presently call “jade” exhibits the typical ontological and epistemological features of an NK. More generally, I expound on why common NKs are more than mere classes, and why categories such as “jade” are useful in many inferences and explanations. (shrink)

If natural kinds have microstructural essences they have them independently of rules for the application of kind terms. This suggests that what those rules are should make no difference to the essences being discoverable. I present two thought-experiments that suggest otherwise, however. Each shows an authority’s application of rules creates the appearance of there being kind essences; absent those rules, the appearance vanishes. This suggests natural kind essences are not independent of authority-sanctioned rules.

Humeans and non-Humeans reasonably agree that there may be necessary connections between entities that are identical or merely partly distinct—between, e.g., sets and their individual members, fusions and their individual parts, instances of determinates and determinables, members of certain natural kinds and certain of their intrinsic properties, and (especially among physicalists) certain physical and mental states. Humeans maintain, however, that as per “Hume’s Dictum”, there are no necessary connections between entities that are wholly distinct;1 and in particular, no necessary causal (...) connections between such entities (even when the background conditions requisite for causation are in place). The Humean’s differential treatment appears principled, in reflecting that commonly accepted necessary connections involve constitutional relations, whereas wholly distinct entities (notably, causes and effects) do not constitute each other. I’ll argue, however, that the appearance of principle is not genuine, as per the following conditional: Constitutional→Causal: If one accepts certain constitutional necessities, one should accept certain causal necessities. This result provides needed leverage in assessing the two main frameworks in the metaphysics of science, treating natural kinds, causes, laws of nature, and the like. These frameworks differ primarily on whether Hume’s Dictum is taken as a working constraint on theorizing; and it has proved difficult for either side to criticize the other without presupposing their preferred stance on the dictum, hence talking past one another. The arguments for Constitutional→Causal are based, however, in general and independent considerations about what facts in the world might plausibly warrant our beliefs in certain constitutional necessities involving broadly scientific entities. The Humean can respond to these arguments, which reveal a deep tension in their view, at attendant costs of implausibilty and adhocery. The non-Humean framework doesn’t face any such tension between constitutional and causal necessities, however, and so in this respect comes out ahead. (shrink)