Substance theory
Substance theory, or substance–attribute theory, is an ontological theory positing that objects are constituted each by a substance and properties borne by the substance but distinct from it. In this role, a substance can be referred to as a substratum or a thing-in-itself.[1][2] Substances are particulars that are ontologically independent: they are able to exist all by themselves.[3][4] Another defining feature often attributed to substances is their ability to undergo changes. Changes involve something existing before, during and after the change. They can be described in terms of a persisting substance gaining or losing properties.[3] Attributes or properties, on the other hand, are entities that can be exemplified by substances.[5] Properties characterize their bearers; they express what their bearer is like.[4]
Substance is a key concept in ontology, the latter in turn part of metaphysics, which may be classified into monist, dualist, or pluralist varieties according to how many substances or individuals are said to populate, furnish, or exist in the world. According to monistic views, there is only one substance. Stoicism and Spinoza, for example, hold monistic views, that pneuma or God, respectively, is the one substance in the world. These modes of thinking are sometimes associated with the idea of immanence. Dualism sees the world as being composed of two fundamental substances (for example, the Cartesian substance dualism of mind and matter). Pluralist philosophies include Plato's Theory of Forms and Aristotle's hylomorphic categories.
Criticism of soul as substance[edit]
Kant observed that the assertion of a spiritual soul as substance could be a synthetic proposition which, however, was unproved and completely arbitrary.[25] Introspection does not reveal any diachronic substrate remaining unchanged throughout life. The temporal structure of consciousness is retentive-perceptive-prognostic. The selfhood arises as result of several informative flows: (1) signals from our own body; (2) retrieved memories and forecasts; (3) the affective load: dispositions and aversions; (4) reflections in other minds.[26] Mental acts have the feature of appropriation: they are always attached to some pre-reflective consciousness.[27] As visual perception is only possible from a definite point of view, so inner experience is given together with self-consciousness. The latter is not an autonomous mental act, but a formal way how the first person has their experience. From the pre-reflective consciousness, the person gains conviction of their existence. This conviction is immune to false reference.[28] The concept of person is prior to the concepts of subject and body.[29] The reflective self-consciousness is a conceptual and elaborate cognition. Selfhood is a self-constituting effigy, a task to be accomplished.[30] Humans are incapable of comprising all their experience within the current state of consciousness; overlapping memories are critical for personal integrity. Appropriated experience can be recollected. At stage B, we remember the experience of stage A; at stage C, we may be aware of the mental acts of stage B. The idea of self-identity is enforced by the relatively slow changes of our body and social situation.[31] Personal identity may be explained without accepting a spiritual agent as subject of mental activity.[32] Associative connection between life episodes is necessary and sufficient for the maintenance of a united selfhood. Personal character and memories can persist after radical mutation of the body.[33]
Religious philosophy[edit]
Christianity[edit]
The Christian writers of antiquity adhered to the Aristotelian conception of substance. Their peculiarity was the use of this idea for the discernment of theological nuances. Clement of Alexandria considered both material and spiritual substances: blood and milk; mind and soul, respectively.[43] Origen may be the first theologian expressing Christ's similarity with the Father as consubstantiality. Tertullian professed the same view in the West.[44] The ecclesiastics of the Cappadocian group (Basil of Caesarea, Gregory of Nyssa) taught that the Trinity had a single substance in three hypostases individualized by the relations among them. In later ages, the meaning of "substance" became more important because of the dogma of the Eucharist. Hildebert of Lavardin, archbishop of Tours, introduced the term transubstantiation about 1080; its use spread after the Fourth Council of the Lateran in 1215.
According to Thomas Aquinas, beings may possess substance in three different modes. Together with other Medieval philosophers, he interpreted God's epithet "El Shaddai" (Genesis 17:1) as self-sufficient and concluded that God's essence was identical with existence.[45] Aquinas also deemed the substance of spiritual creatures identical with their essence (or form); therefore he considered each angel to belong to its own distinct species. In Aquinas' view, composite substances consist of form and matter. Human substantial form, i.e. soul, receives its individuality from body.[46]