substance sortal

Definition and Core Idea

A substance sortal is a kind of sortal concept that applies to persisting, countable substances—entities that endure through time and can be reidentified as the same individual despite change. In analytic metaphysics and philosophy of language, a sortal is a concept under which things are counted and individuated (for example, cat, tree, person). A substance sortal is a privileged subset of such concepts: it is supposed to provide a criterion of identity over time for the things that fall under it.

Typical examples of substance sortals include “person,” “cat,” “ship,” “table,” or “organism.” These contrast with:

• Phase sortals, such as “adolescent,” “student,” “embryo,” which describe a temporary phase or role of something that is already an instance of a substance sortal.
• Mass terms, such as “water,” “gold,” “furniture” (in some usages), which do not straightforwardly pick out individual, countable entities with their own criteria of identity.

Thus, calling a term a substance sortal implies that:

1. It applies to individuals (not just stuff or quantities).
2. It allows for counting (how many Xs are there?).
3. It includes or presupposes a principle for when an X at one time is the same X at another time.

Historical Background and Key Thinkers

The notion of a sortal, and specifically a substance sortal, emerges in 20th‑century analytic philosophy, drawing on both Aristotelian ideas of substance and Kantian concerns with conditions of objective experience.

P. F. Strawson is widely credited with introducing a systematic use of sortals in Individuals (1959). For Strawson, ordinary language contains basic sortal concepts—terms like person, material body, animal—under which we pick out and track particulars. These basic sortals function roughly as substance sortals: they provide the logical and practical framework for individuating and reidentifying objects.

David Wiggins developed the notion more explicitly in works such as Sameness and Substance (1980) and Sameness and Substance Renewed (2001). Wiggins emphasizes that a substance sortal carries a criterion of identity: it determines what it is to be the same F across time. For instance, for an organism, the criterion might involve biological continuity; for a artifact like a ship, it may involve continuity of structure and function.

Lynne Rudder Baker integrates substance sortals into her constitution view of persons. For Baker, “person” is a primary substance sortal, under which beings exist and persist in a way not reducible to merely biological or physical sortals. On her account, the same human organism may, at some point, constitute a person, but the person is understood through the substance sortal person and its own identity conditions.

Other contributors include Michael Ayers, E. J. Lowe, and various metaphysicians of persistence and personal identity. While terminology and emphasis differ, the shared idea is that substance sortals are central to explaining how objects are counted, individuated, and tracked in thought and language.

Substance Sortals, Identity, and Persistence

Philosophically, substance sortals are invoked to explain three interconnected notions: identity, persistence, and reference.

1. Identity through time
   Proponents hold that to ask whether entity a at time t1 is the same as entity b at time t2 is always to ask whether they are the same under some sortal. The identity question, they argue, is incomplete without specifying the relevant sortal: “the same what?” A substance sortal like cat or person encodes rules about when continuity (of body, brain, psychology, function, or something else) suffices for numerical identity.

2. Persistence and change
   Substance sortals back a distinction between essential and accidental properties. For an entity falling under a given substance sortal, certain changes are allowed while it remains the same substance; other changes might terminate its existence as that kind of thing. For example, a person may change dramatically in appearance and knowledge yet remain the same person; but ceasing to have the relevant psychological or first-person capacities might, on some accounts, end the existence of that person.

3. Reference and singular terms
   In philosophy of language, sortals (and especially substance sortals) are thought to shape how we refer to individuals. Some theorists argue that successful singular reference—using expressions like “this cat,” “that ship,” “Socrates”—presupposes a substance sortal under which the referent is identified. Without any sortal framework, the idea of singling out an object as “one” thing among others may be unintelligible.

The distinction between substance sortals and phase sortals illustrates these roles. Student is often cited as a phase sortal: something is a student only because it is already a person (or at least an intelligent agent) going through a particular stage or role. The criterion of identity for a student is derivative on, and cannot be understood independently of, the criterion for a person. Hence person is treated as a substance sortal; student is not.

Contemporary Debates and Criticisms

The appeal to substance sortals has been influential but contested.

Supporters argue that:

• It captures an important feature of ordinary conceptual practice: we typically think of objects under kind-concepts that guide counting and reidentification.
• It helps clarify debates on personal identity, where different substance sortals (e.g., animal, person, psychological subject) may yield different verdicts about survival in thought experiments such as brain transplants or teleportation.
• It links metaphysics and language, explaining how identity questions are intimately tied to the structure of our concepts and linguistic categories.

Critics raise several concerns:

1. Conceptual relativity: Some philosophers question whether identity really is always sortal-relative. They suggest that the notion of numerical identity—being one and the same entity—may make sense independently of any particular sortal.

2. Ontological commitment: Others question whether metaphysics should take ordinary sortal classifications as guides to what exists fundamentally. On more revisionary or deflationary views, substance sortals may reflect our cognitive or linguistic practices more than they reveal deep ontological structure.

3. Vagueness and borderline cases: Real-world categories often have blurry boundaries. It can be unclear what the exact criterion of identity for many alleged substance sortals is, or whether there even is a single precise criterion. This raises worries about tying metaphysical identity too tightly to such concepts.

4. Alternative frameworks: Accounts of persistence based on four-dimensionalism (which treats objects as extended in time like they are in space) sometimes downplay the need for substance-sortal-based identity conditions, instead appealing to temporal parts and spatiotemporal relations.

Despite these debates, substance sortal remains a central technical term in discussions of identity over time, objecthood, and the relationship between language, thought, and reality. It continues to be used both by those who embrace its metaphysical significance and by critics who take it as a useful target for clarification or revision.