Online research in philosophy

This paper opposes universal mereological composition (UMC). Sider defends it: unless UMC were true, he says, it could be indeterminate how many objects there are in the world. I argue that there is no general connection between how widely composition occurs and how many objects there are in the world. Sider fails to support UMC. I further argue that we should disbelieve in UMC objects. Existing objections against them say that they are radically unlike Aristotelian substances. True, but there is a stronger objection. This is that they are characterized by no properties, and so fail to be like anything – even themselves.

Aristotelian, or non-Platonist, realism holds that mathematics is a science of the real world, just as much as biology or sociology are. Where biology studies living things and sociology studies human social relations, mathematics studies the quantitative or structural aspects of things, such as ratios, or patterns, or complexity, or numerosity, or symmetry. Let us start with an example, as Aristotelians always prefer, an example that introduces the essential themes of the Aristotelian view of mathematics. A typical mathematical truth is that there are six different pairs in four objects: Figure 1. There are 6 different pairs in 4 objects The objects may be of any kind, physical, mental or abstract. The mathematical statement does not refer to any properties of the objects, but only to patterning of the parts in the complex of the four objects. If that seems to us less a solid truth about the real world than the causation of flu by viruses, that may be simply due to our blindness about relations, or tendency to regard them as somehow less real than things and properties. But relations (for example, relations of equality between parts of a structure) are as real as colours or causes.

Some recently-proposed counterexamples to the traditional definition of essential property do not require a separate logic of essence. Instead, the examples can be analysed in terms of the logic and theory of abstract objects. This theory distinguishes between abstract and ordinary objects, and provides a general analysis of the essential properties of both kinds of object. The claim ‘x has F necessarily’ becomes ambiguous in the case of abstract objects, and in the case of ordinary objects there are various ways to make the definition of ‘F is essential to x’ more fine-grained. Consequently, the traditional definition of essential property for abstract objects in terms of modal notions is not correct, and for ordinary objects the relationship between essential properties and modality, once properly understood, addresses the counterexample.

Our day-to-day experience of the world regularly brings us into contact with middlesized objects such as apples, dogs, and other human beings. These objects possess observable properties, properties that are available or accessible to the unaided senses, such as redness and roundness, as well as properties that are not so available, such as chemical ones. Both of these kinds of properties serve as valuable sources of information about our familiar middle-sized objects at least to the extent that they enable us to understand the behaviours of those objects and their effects on each other and on us. I see the apple on the table before me, and in doing so I see its redness, its roundness, and so on. I do not see, but know that it has, a certain chemical constitution. The knowledge gained of the apple by means of both properties tells me something about the nature of that apple. In general, most, if not all, of the properties that objects in the observable world possess serve as the basis of our knowledge of such objects. But the subject-predicate form of much of our discourse and thought about objects suggests that substances are one kind of thing, properties another. We use subject terms such as names to identify objects, predicate terms to attribute properties to them. What, then, is it for an object to have a property? And what is the relation between an object and its properties?

Modal conventionalism is the view that two crucial forms of sameness are mind-dependent. There is no phenomenon of sameness in kind, on this view, except in virtue of our conventions for individuating nature’s kinds; there is no phenomenon of numerical sameness across time, for an individual member of some natural kind, except in virtue of our conventions for individuating such members.1 Modal conventionalism has its realist opponents. These opponents have argued, following Kripke’s lead more than thirty years ago (Kripke 1972), that the boundaries of at least many of nature’s kinds are carved out by nature itself, and not by our classifi catory practices (e.g., Millikan 2000: passim, e.g., pp. 25 and 72). But they have not generally argued, with anything approaching the same vigor, that modal conventionalism is wrong in its other main claim. They have not in general argued that the world-given connections among properties, that make those properties mind-independently be membership conditions for some natural kind, at the same time make those properties mind-independently be persistence conditions for the members of the kind—properties the departure of which constitutes a ceasing-to-exist for the object that formerly had them. On the contrary, opponents of modal conventionalism have..

To be a realist about modality, need one claim that more exists than just the various objects and properties that populate the world—e.g. worlds other than the actual one, or maximal consistent sets of propositions? Or does the existence of objects and properties by itself involve the obtaining of necessities (and possibilities) in re? The latter position is now unpopular but not unfamiliar. Aristotle held that objects have essences, and hence necessarily have certain properties. Recently it has been argued that the identity of any property is tied to the natural laws in which it figures, which entails that the occurrence of properties involves the obtaining of nomological necessities ([24], pp. 206-33 and 234-60; [23]; cf. [25] and [6]). Somewhat less recently, Wittgenstein ([28], p. 168) worried that the reality of at least some properties—precise shades of colors being a prime example—involved the obtaining in re of certain impossibilities. This paper argues that Wittgenstein’s worries were right, and not just concerning some properties, but all properties whatever. That there are objects and properties in the world at all, then, amounts to there obtaining modal states of affairs. This argument supplements, rather than replaces, the others. The position on property incompatibility advanced here actually helps defend Aristotelian essentialism against epistemological objections, or so I have argued ([15]). And while this paper’s position on property incompatibility diverges from the idea that a property’s nomic profile is essential to it—more on this in the next section—it is at least compatible with the thought that the necessity involved in the laws of nature enters into ontology at the ground level.

If an object has a property essentially, it has that property in every possible world according to which it exists.2 If an object has a property accidentally, it does not have that property in every possible world according to which it exists. Claims about an object’s essential or accidental properties are de re modal claims, and essential and accidental properties are de re modal properties. Take an object’s modal profile to specify its essential properties and the range of its accidental properties. Note that “world” as I am using it is a term of art: a modal realist believes that there are many concrete worlds, while the actualist believes in only one concrete world, the actual world. The ersatzist is an actualist who takes nonactual possible worlds and their contents to be abstracta. Essentialism is the view that objects have properties essentially, but one should distinguish deep essentialism from shallow essentialism. Deep essentialists take the (nontrivial) essential properties of an object to determine its nature— such properties give sense to the idea that an object has a unique and distinctive character, and make it the case that an object has to be a certain way in order for it to be at all.3 As Stephen Yablo (1987, 297) describes it, the essence of a thing is “an assortment of properties in virtue of which it is the entity in question,” as well as “a measure of what is required for it to be that thing.” Intuitively, on the deep essentialist picture, an ordinary object has essential properties, and it must have its essential properties in order for it to exist. On this view, objects’ essential properties are absolute, i.e., are not determined by contexts of describing (or thinking, etc.) about the object, and truths about such properties are absolute truths.4 Shallow essentialists oppose deep essentialists: they reject the view that objects can be said to have essential properties independently of contexts of description or evaluation, and so substitute context-dependent truths for the deep essentialist’s context-independent ones..

Realism about material objects faces a variety of epistemological objections. Recently, however, some realists have offered new accounts in response to these long-standing objections; many of which seem plausible. In this paper, I raise a new objection against realism vis-à-vis how we could empirically come to know mind-independent essential properties for objects. Traditionally, realists hold kind-membership and persistence as bound together for purposes of tracing out an object’s essential existence conditions. But I propose kind-membership and persistence for objects can conceptually come apart and function epistemologically distinctly from one another—in which case the usual reliance by realists on an assumption of persistence to determine kind-membership conditions is unjustified. Thus, present realist attempts to explain how empirical detection of mind-independent essential properties for objects could possibly occur inevitably results in circularity. The charge against the realist is to explain why we don’t have to first discover persistence conditions for an object before we can ascertain kind-membership conditions for an object. If no answer is forthcoming, then it seems the weight of the epistemological objection to realism is back in full force.

The paper spells out five different accounts of the relationship between objects and relations three of which are versions of ontic structural realism (OSR). We argue that the distinction between objects and properties, including relations, is merely a conceptual one by contrast to an ontological one: properties, including relations, are modes, that is the concrete, particular ways in which objects exist. We then set out moderate OSR as the view according to which irreducible relations are central ways in which the fundamental physical objects exist. Physical structures thus consist in objects for whom it is essential that they are related in certain ways. There hence are objects, but they do not possess an intrinsic identity. This view can also admit intrinsic properties as ways in which objects exist provided that these do not amount to identity conditions for the objects. Finally, we indicate how this view can take objective modality into account.

Historically, opponents of realism have managed to slip beneath a key objection which realists raise against them. The opponents say that some element of the world is constructed by our cognitive practices; realists retort that the element would have existed unaltered, had our practices differed; the opponents sometimes agree, contending that we construct in just such a way as to render the counterfactual true. The contemporary instalment of this debate starts with conventionalism about modality, which holds that the borders of the world's kinds and the careers of individuals in those kinds obtain only relative to our conventions of individuation. Realists object that the kinds and careers in nature would still have obtained, had our conventions been different, but conventionalists claim to be able to agree. I argue that this claim is false, and that conventionalism contradicts itself.