William C. Wimsatt (1997), Philosophy of Science 64(S4):S372–S384 (Proceedings of the 1996 Biennial Meeting of the Philosophy of Science Association, Part II; Symposium “Emergence and Supervenience: Alternatives to Unity by Reduction”) — DOI-10.1086/392615
Key takeaways
Not read. The first item is the publisher’s abstract. The others are Wimsatt’s own later summary in “Reductionism and its heuristics” (Synthese, 2006, §2 and §8), which was read in those sections and is not filed.
- Emergence is the failure of aggregativity, and is compatible with reduction. The abstract: “Most philosophical accounts of emergence are incompatible with reduction. Most scientists regard a system property as emergent relative to properties of the system’s parts if it depends upon their mode of organization—a view consistent with reduction. Emergence can be analyzed as a failure of aggregativity—a state in which ‘the whole is nothing more than the sum of its parts.’ Aggregativity requires four conditions, giving tools for analyzing modes of organization.”
- The four conditions, as Wimsatt later summarises them. For any decomposition of the system into parts, an aggregative property is “invariant over appropriate rearrangements, substitutions, and reaggregations”, and its value “scale[s] appropriately under additions or subtractions” of parts (Synthese 2006, §8). Mass, energy, momentum and charge qualify; “even the shape … of a pile of rocks is not aggregative”.
- Aggregativity comes in degrees. Invariance under some operations, under some conditions or within tolerances “makes partial aggregativity a multi-dimensional degree property”, “a partial ordering scheme of great richness for classifying kinds of emergence” (§8). Simple models start aggregative and lose it as organisation is added (§2).
Standing in the record
Filed on 2026-10-04 at the owner’s request, Deferred because it could not be read lawfully. It is the record’s statement of emergence as non-aggregativity, and Wimsatt has so far been held only at second hand: Kendler (LIT-539, read in NOTE-432) uses his aggregativity criteria for psychiatric explanation, and Griesemer (LIT-188, NOTE-173) uses “aggregative” and Wimsatt’s generative entrenchment. No anthology topic holds it.
On emergence, with List and Pettit (LIT-705). The owner asked whether group agents and aggregativity disagree about emergence. On what has been read, they do not, because they mean different things by the word. List and Pettit reject emergence as agency arising “mysteriously, without a clear basis at the level of individuals”, and keep individualism. Wimsatt’s emergence is dependence on the organisation of parts, which he holds compatible with reduction. List and Pettit’s theorems show that a rational group’s judgments cannot depend on members’ judgments proposition by proposition, and that set-wise dependence can be invariant under permuting the members or not. In Wimsatt’s terms that is a proof that group judgment is non-aggregative, hence emergent and reductively explicable. The comparison is the record’s, not the authors’: neither cites the other. No relation is declared until this paper is read.
The same point bears on Huebner (LIT-702). His “genuinely collective” emotion is one that is not members’ states “in aggregation”. Wimsatt’s conditions would make “aggregation” exact.
What a reading should check.
- The exact statement of the four conditions, and whether “substitution” is intersubstitution of parts within an equivalence class.
- Whether the conditions apply to a function from members’ attitudes to a group’s, where the “parts” are people and the “property” is an attitude, or only to physical systems.
- How the paper treats a system aggregative under one decomposition and not another, which is the case of the premise-based procedure (aggregative premise by premise, not over the whole agenda).