Metaphysical Dualism is a philosophical school based on the idea of ‘the Two-Worlds View’. The defining feature of metaphysical dualism is the doctrine that there are only two kinds of substances: material objects and rational souls. The only mental substances are minds. Thinking or thought is essentially a mode of mental substance. This metaphysical doctrine is inseparable from the conception of the logical forms of singular judgments. Nothing other than a mind (or soul) can be the logical subject of a judgment whose logical predicate is an incorporeal property.
For a dualist, the world “… can be divided into physical things, states and events which are in space and fallibly known and mental things, states and events which are not in space and are either infallibly known or are only identifiable by their analogy to things that are” (Cottingham, p. 43). Dualism equates the mind with consciousness. The world of physical objects is known through sense-perception and the other world (of mental objects) is known through infallible introspection (Cottingham, p. 43). Dualism is based on the idea of two equal and coextensive factors or members. All knowledge is relative, and all existence is relative existence. Duelists suppose that the interaction between mind and body is ‘rationally unintelligible’; in a human being, a mind and a body are ‘substantially united’ (Loeb, p. 65). Our Nature as the union of mind and body underlies both the faculty of sense-perception and the capacity for voluntary action (Loeb, p. 65). There are two kinds of substances: corporeal things and thinking things (minds or rational souls). The properties of minds are all modes of thinking; the properties of bodies are all modes of extension. The distinction between substances and modes is absolute. Since only a thing (a substance) can be the logical subject of a judgment, there are only two kinds of logical subjects of predication: ‘res extensive and rational souls (Loeb, p. 65). Hence there are no ‘mental particulars’ other than minds. The Two-Worlds View, from Descartes’ perspective, exemplifies the fundamental confusion of treating modes as substances.
Rene Descartes, Plato, and F. Hegel are the main contributors who developed and extended the study of dualism. Rene Descartes is considered the major contributor who developed and described Metaphysical Dualism. His main work is Meditations on the First Philosophy. Descartes characterizes a person as ‘a composite thing’, a combination of a body (a corporeal substance) and a rational soul (an incorporeal substance). This is the indisputable core of his dualism (Voss, p. 48). He adds that a person is ‘a substantial union’ of mind and body; in a person, the soul and the body are ‘intimately conjoined and, as it were, intermingled’, etc (Voss, p. 48). All interactions between mind and body are one way, with the mental realm standing as cause and the physical as effect (Cottingham, p. 43).
Descartes supposes that the mind and body of a person are ‘glued’ together by various kinds of causal interaction: in sense-perception, changes in the body bring about changes in perceptual experiences, while involuntary action, mental entities bring about bodily movements (Garber, p. 82). There is a tendency to conceive of efficient causation as a relation between things or particulars. Following Descartes, the essence of the mind is thought, the essence of the body is the extension. The boundary between the mind and the body is grounded in the distinction between the intelligent (the rational, the intellectual, hence the moral) and the mechanical (the instinctive, the automatic, the causally determined) (Garber, p. 82). The notion of substances plays a crucial role in his analysis of the logical forms of judgments: every singular judgment must predicate a property of a substance. It must predicate of a mind a mode of thinking or a corporeal substance a mode of extension. These two schemata exhaust the logical structures of singular judgments (Garber, p. 88).
The concept of dualism can be found in Plato and his explanation of the world. Plato describes his views and understanding of the world in the Theory of Forms. Before Descartes, he had proved that the objects (we can see) are nothing more than shadows of forms. One of my main arguments against the view that forms are meanings appeals to arguments for the existence of forms. Plato does not offer semantic arguments for the existence of forms (Loeb, p. 34). His arguments are all epistemological, metaphysical, or both. Plato argues that the possibility of knowledge requires the existence of forms, where the sort of knowledge at issue is not ordinary linguistic understanding, but knowledge as it contrasts with belief; he also argues that we can explain the way the world is only if there are forms in virtue of which things are as they are. These two sorts of arguments are connected, for Plato believes that the possibility of knowledge requires the existence of forms conceived as real properties of things (Perry and Bratman, p. 567). If Plato does not use semantic arguments for the existence of forms, forms might nonetheless be meanings or be relevant to explaining the meaningfulness of general terms. But the absence of semantic concerns in Plato’s discussions of forms casts doubt on the most prominent reasons for supposing that forms play any semantic role (Voss, p. 92).
F. Hegel extended the idea of dualism and developed a dialectic concept of the world. His dualism is based on the opposition between ‘thesis’ and ‘antithesis’. Nature and Spirit are two aspects, two manifestations, of the Absolute realizing itself in history (Loeb, p. 92). This position is a form of dualism (in that it takes both mental and material events to be real and distinguishable) but it retains its materialistic credentials by declaring all psychological outcomes to be causally determined by physiological antecedents. The mind (soul) can influence the course of bodily events but is itself independent of such purely material influences. This correlation is also highly debated, and each idea gains supremacy (Perry and Bratman, p. 328)
Hegel underlines that it is only metaphysical dogmatism, such as that displayed by dualists, empiricists, materialists, and natural scientists, that requires sharp boundaries between body and soul, cause and effect, potentiality, and real existence. Confining themselves either to the contentless world of logical formalisms or the half-true world of mere appearances, the dogmatists are unable to comprehend real beings (Loeb, p. 93) The dialectical ontology repairs this by establishing reality on the plane of “the identity of opposites. For Hegel, the individual’s “psychology” is a moment in the dialectical movement of the Absolute Idea (Loeb, p. 94). The branch of philosophy concerned with moments such as these is what he calls the philosophy of spirit which examines either the subjective (soul) or objective (mind) manifestations of the infinite in the finite. Only the philosophy of the Absolute transcends this duality and comprehends each in the other (Loeb, p. 94). Hegel’s evolutionary metaphysics marks the stages of the spirit’s development. These begin at the level of the natural soul and pass successively through subjective mind, objective mind, and absolute spirit. The natural soul, in its ‘unawakened’ state, is simply the life of nature. “Nature herself,” says Hegel, “begins to overcome its externality” (Loeb, p. 87) in the forging of animal instincts and cravings. Through the dialectical opposition of the purely vegetative and the ‘nonvegetative’, however, the natural soul becomes awakened (Loeb, p. 87). Awakened to itself, the soul nonetheless is unconscious of its immersion in the organic world. Where the natural soul controls and self-conscious soul obeys, depression and even insanity may result (Loeb, p. 98).
Something that I found interesting about Metaphysical Dualism is that the Two-Worlds View is a doctrine that makes sense of something unintelligible. I suppose that the main limitations of dualism are that it simplifies interactions and relations between body and mind. The doctrine seems all at once captivating, pernicious, and demonstrably confused. Second, it is thought to give a correct interpretation, at least in broad outline, of Descartes’ reflections on the nature of a person. Metaphysical Dualism is a debatable topic, and Descartes himself notes and criticizes a parallel movement of thought in the case of ‘real attributes’ or ‘substantial forms’. In his view, the scholastic doctrine that ‘heaviness’ or ‘gravity can cause the movement of the matter rests on mistaking modes of material things for things or substances in their own right (Cottingham, p. 32). It is possible to underline the subjectivity of this school. Mind is grounded in indubitable reports of the occurrence or existence of various states of consciousness. Various conclusions are drawn about the impossibility of objective human knowledge. Thus many critics (Garber, p. 33) have accused Descartes of being committed to skepticism about other minds as well as embarking on an epistemological project that is self-evidently hopeless. I suppose that the limitation of this theory is that it does not recognize the senses. It misses out on crucial aspects both of the mind and the senses.
Works Cited
- Cottingham, J. The Cambridge Companion to Descartes (Cambridge Companions to Philosophy). Cambridge University Press, 1992.
- Garber, Daniel, Descartes’ Metaphysical Physics, Chicago: University of Chicago Press, 1992.
- Loeb, Louis, From Descartes to Hume, Ithaca: Cornell University Press, 1981.
- Perry, J., Bratman, M. Introduction to Philosophy: Classical and Contemporary Readings. Oxford University Press, USA; 3 edition, 1998.
- Voss, Stephen (ed.) Essays on the Philosophy and Science of René Descartes, Oxford: Oxford University Press, 1993.