2
Ontology, Logic, and Philosophy of Language
What Is the Structure of the World?

In Chapter 2 we focus on problems concerning the structure of the world. This kind of structure is traditionally conceived as ontological, or categorial, structure. For Aristotle, who introduced the term, "categories," or "things said" of a subject, are the most fundamental aspects of being, the ultimate classifications into which all objects, facts, processes, and events must ultimately fall. In the modern period, Kant argued that categories are grounded in the structure of human thought and provide the most general conditions under which we can conceptualize the world. For much of twentieth-century philosophy, categories and categorial structures were instead understood as aspects of language or languages. Many contemporary debates turn on the choice among these three models (sections 2.1 and 2.2). These debates are closely connected to others about the nature of logic (section 2.3). For early analytic philosophers such as Ludwig Wittgenstein and Rudolf Carnap, fundamental categories are aspects of "logical forms" or "conceptual frameworks" that structure the world as we know it by determining the structure of the language we use to describe it. Likewise, some continental philosophers, including Martin Heidegger and thinkers influenced by the structural linguist Ferdinand de Saussure, have held that particular languages impose categorial structures that vary dramatically over time and from culture to culture, while other philosophers of both traditions have challenged this idea. One guiding question in this debate is whether logic imposes a categorial framework on the world, and, if so, how (section 2.4).

A more specific problem in ontology is which categories are the most fundamental. Analytic and continental philosophers alike have considered the nature of things (section 2.5) and events (section 2.6). They have wondered what a thinking subject is, whether subjectivity is essentially gendered, and what self-reference involves (section 2.7). This last issue connects to more general questions about the nature of reference (section 2.8), which in turn connect to problems about the nature of modality and possible worlds (section 2.9). We conclude our discussion of ontology and logic by looking at debates about the nature of identity and difference, general concepts that cut across categorial structures, however the latter are interpreted (section 2.10).

2.1    Does the world have an intrinsic categorial structure?

In his brief treatise "Categories," Aristotle introduces the term to philosophical discourse and gives the first inventory and description of the overall structure of categories, or types of things, events, and processes. Drawing on the etymology of the term in Greek, Aristotle understands categories as "things said" (and thus as types of language or linguistic terms), but also as general types into which objects, events, and properties fit, providing a kind of complete, high-level 'inventory' of the constituents of the world (Thomasson, 2013). Here he gives, as well, the first specific list of ten categories or "things said without any combination" (Aristotle, 1984: 4 [1b25-2a4]). The list is: substance, quantity, qualification, relative, where, when, being-in-a-position, having, doing, being-affected. In contemporary discussion, "categories" are sometimes identified as any conceptual types whatsoever, whereas in other discussions, they retain the significance of the highest or most general kinds or types under which anything falls, as in Aristotle's treatment.

In the Critique of Pure Reason, Kant complains that Aristotle's original structure of ten categories is lacking in motivation (Kant, 1998 [1781/1787]: A81/B107). Why should there be just ten categories, and why these particular ones? Arguing from a "transcendental idealist" perspective, Kant first maintains that two of Aristotle's categories - where and when - are not categories at all, since they pertain to spatio-temporal conditions of sensibility that are first needed to make any categorial determinations possible. Kant further holds that any possibility for spatiotemporal objects to exist objectively is in fact grounded in the constitutive forms or faculties of the cognizing subject. In particular, the structure of categories that determines the nature of real, objective things and their relations is grounded in the logical forms of possible judgments made by the "understanding," the faculty of conceptual representation and judgment (Kant, 1998 [1781/1787]: A66-95/B92-128). For instance, the fact that spatiotemporal objects are able to affect one another causally is grounded in a particular form of relational judgment, the "hypothetical" (if-then) judgment. Accordingly, Kant derives four types of categories from the four logical aspects of the judgments we can make about objects. These types are: Quantity, Quality, Relation and Modality (with three further sub-divisions in each broad category). For Kant, the most general categories of the possible structures of objects are thus not intrinsic to things as they are in themselves, or to the world considered independently of the cognizing subject, since they are determined and formed by the logical aspects of judgments of which a cognizing subject is capable. Nevertheless, they remain essential aspects of the structure of any spatiotemporal object whatsoever.

Expanding and modifying this transcendental idealist approach to categories within his own phenomenological project, Husserl argues that phenomenologically accessible categories of meaning correlate to the possible types or "essences" of objects. Although these categories are accessible in phenomenological reflection, they are also thought of as determining the ontological structure of the world and the types of both sensory and non-sensory objects. For Husserl, essences are knowable by means of one of two kinds of intuition: categorial intuition (Husserl, 1977 [1901]; Husserl, 1969 [1929]) yields access to non-sensory categories corresponding to "syncategorematic" terms such as "on," "not" and the predicative "is," whereas eidetic intuition yields access to essences of objects and their perceptually experienceable properties (see section 1.1). These two types of intuition jointly yield access to abstract laws of essence that allow for the definition of the ideal categories of things (Husserl, 1977 [1901]: "Prolegomena" and Investigation VI). Through eidetic and categorial intuition it is possible to establish two kinds or levels of ontological categories: categories of formal ontology hold for any type of object (or objectivity) whatsoever, whereas categories of (various) regional ontologies establish the types of objects and situations treated by specific scientific disciplines and theories. For Husserl, ontological ideal categories are thus accessible in subjective phenomenological reflection but nevertheless determine the real structure of objects, events, and properties in the world.

In Being and Time, Heidegger suggests that the traditional understanding of the world in terms of categories of objects and their properties is itself the outcome of an over-emphasis on predicative judgment, and a privileging of what is actually only a certain way of being, that of the "present-at-hand" [Vorhanden] (Heidegger, 1962 [1927]: sections 15-17). Rather than focusing exclusively on objects that are "present-at-hand" before us and accessible to theoretical cognition, we should ground our understanding of the structure of objects in a broader and existentially deeper fundamental ontology that begins with the analysis of Dasein, the kind of being that we ourselves are. In this investigation, the traditional inquiry into the constitutive categories of objects is replaced with an inquiry into the "existentials" or structures of Dasein as, in each case, a living individual defined by its particular possibilities and the structure of care and temporality involved in this structure of possibilities.

A different approach is taken by early analytic philosophers who see the logical or grammatical structure of language as yielding fundamental categorial structures. Gottlob Frege investigated the logical structure of language in order to determine the structure of possible contents of thought. In line with this project, Frege drew a fundamental categorial distinction between objects and concepts as distinct logical types (Frege, 1997 [1892]). Objects are the referents of names, whereas concepts correspond to predicative and relational expressions. These expressions, such as ".is red" or ".is taller than.," are not names, but rather refer to functions taking objects to truth-values. Both of these types of expressions (names as well as predicative or relational ones) are needed to form a declarative sentence that is either true or false. For example, a particular apple, A, may be said simply to exist, but the predicative expression ".is red" has no referent capable of such independent existence. Rather, we may think of the referent of the predicative expression as a function which takes...