individualism, methodological See METHODOLOGI-. CAL HOLISM. individuation, (1) in metaphysics, a process whereby a universal, e.g., cat, becomes instantiated in an individual – also called a particular e.g., Minina; (2) in epistemology, a process whereby a knower discerns an individual, e.g., someone discerns Minina. The double understanding of individuation raises two distinct problems: identifying the causes of metaphysical individuation, and of epistemological individuation. In both cases the causes are referred to as the principle of individuation. Attempts to settle the metaphysical and epistemological problems of individuation presuppose an understanding of the nature of individuality. Individuality has been variously interpreted as involving one or more of the following: indivisibility, difference, division within a species, identity through time, impredicability, and non-instantiability. In general, theories of individuation try to account variously for one or more of these. Individuation may apply to both substances (e.g., Minina) and their features (e.g., Minina’s fur color), generating two different sorts of theories. The theories of the metaphysical individuation of substances most often proposed identify six types of principles: a bundle of features (Russell); space and/or time (Boethius); matter (Aristotle); form (Averroes); a decharacterized, sui generis component called bare particular (Bergmann) or haecceity (Duns Scotus); and existence (Avicenna). Sometimes several principles are combined. For example, for Aquinas the principle of individuation is matter under dimensions (materia signata). Two sorts of objections are often brought against these views of the metaphysical individuation of substances. One points out that some of these theories violate the principle of acquaintance, since they identify as individuators entities for which there is no empirical evidence. The second argues that some of these theories explain the individuation of substances in terms of accidents, thus contradicting the ontological precedence of substance over accident.
The two most common theories of the epistemological individuation of substances identify spatiotemporal location and/or the features of substances as their individuators; we know a thing as an individual by its location in space and time or by its features. The objections that are brought to bear against these theories are generally based on the ineffectiveness of those principles in all situations to account for the discernment of all types of individuals.
The theories of the metaphysical individuation of the features of substances fall into two groups. Some identify the substance itself as the principle of individuation; others identify some feature(s) of the substance as individuator(s). Most accounts of the epistemological individuation of the features of substances are similar to these views.
The most common objections to the metaphysical theories of the individuation of features attempt to show that these theories are either incomplete or circular. It is argued, e.g., that an account of the individuation of features in terms of substance is incomplete because the individuation of the substance must also be accounted for: How would one know what tree one sees, apart from its features? However, if the substance is individuated by its features, one falls into a vicious circle. Similar points are made with respect to the epistemological theories of the individuation of features.
Apart from the views mentioned, some philosophers hold that individuals are individual essentially (per se), and therefore that they do not undergo individuation. Under those conditions either there is no need for a metaphysical principle of individuation (Ockham), or else the principle of individuation is identified as the individual entity itself (Suárez). See also BUNDLE THEORY , IDENTITY , META – PHYSICS , PRINCIPIUM INDIVIDUATIONI. J.J.E.G.