Márta Ujvári’s The Trope Bundle Theory of Substance: Change, Individuation and Individual Essence (2013) is a metaphysical analysis of the nature of individual substances as basic building blocks of reality. According to Ujvári’s formulation of the trope bundle theory, individual substances are bundles of qualitative features (tropes). Tropes are individuated via their bearer substances, but substances are individuated via their foundation as bearers of qualitative manifolds qua qualitative manifolds and via their occupation of unique spatiotemporal locations. Thus, the individuation of substances is independent of the fact that each of their constituent tropes is a qualitative feature of them.
This more complex and sophisticated version of the trope bundle theory contrasts with the simple or classical trope bundle theory, which regards an individual substance as “nothing but” a bundle of tropes.1 Ujvári argues that the latter theory fails to account for the unity and concreteness of substances,2 and that it also has the disadvantage of presenting a circular view of individuation, according to which the tropes of an individual substance and the substance itself mutually individuate each other.3
According to Ujvári, tropes are neither particularized properties nor instantiated universals. They are abstract particulars predicable of concrete particulars,4 and they are property particulars belonging to individual substances. Thus, they are not transferable from substance to substance. Each trope depends for its existence on the individual substance to which it belongs.
This version of the trope bundle theory avoids the dilemmas posed by the “strong” version of the Principle of Identity of Indiscernibles (PII), since it does not view tropes as sharable properties.5 Ujvári describes the “strong” version of the PII as the principle that it is impossible for numerically distinct concrete particulars to share all their pure (intrinsic) properties in common,6 while she describes the “weak” version of the PII as the principle that it is impossible for numerically distinct concrete particulars to share all their pure (intrinsic) and impure (spatiotemporal) properties in common.7 She explains that one of the dilemmas posed by the “strong” version of the PII is that property identity is assumed to imply numerical identity.8 This assumption may be false if only intrinsic and not spatiotemporal properties are considered as sharable properties.
Each substance is a bundle of property particulars, rather than a bundle of particular properties or exemplified universals. In contrast to Aristotle’s view of substances as unanalyzable entities, Ujvári views substances as having distinct qualitative features.9
According to the “two-tier modal trope bundle theory,” tropes may be essential or accidental to the identity of an individual substance. Thus, change in an individual substance is possible, because the substance can remain identifiable over time, even if changes occur in some of its tropes.10
Ujvári emphasizes that acceptance of the trope bundle theory does not imply acceptance of a monistic, one-category ontology in which tropes are the basic building blocks of all reality, including entities such as polyadic properties and relations.11
She describes the bundling relation as one of “concurrence” or “compresence” of tropes.12 The internal relations between the tropes of a bundle may be essential or accidental to that particular bundle.13 Since concurrence or compresence cannot logically be an internal relation, it must be a contingent external relation.14
Tropes are constituents of individual substances (continuants), but they may also be events (occurrents). They may also be abstract components of events. Thus, a concrete event may include all the tropes of the particular substance it involves, but the substance may also exist in its own right as a continuant.15
1Márta Ujvári, The Trope Bundle Theory of Substance: Change, Individuation and Individual Essence (Frankfurt: Onto Verlag, 2013), p. 25.
2Ibid., p. 127
3Ibid., p. 25.
4Ibid., pp. 16-18.
5Ibid., p. 58.
6Ibid., p. 53
7Ibid., p. 52.
8Ibid., p. 51.
9Ibid., p. 25.
10Ibid., p. 20.
11Ibid., pp. 15-16.
12Ibid., p. 157.
13Ibid., p. 158.
14Ibid., p. 161.
15Ibid., pp. 67-68.