Materialism
Materialism is a form of philosophical monism which holds that matter is the fundamental substance in nature, and that all things, including mental states and consciousness, are results of material interactions of material things. According to philosophical materialism, mind and consciousness are caused by physical processes, such as the neurochemistry of the human brain and nervous system, without which they cannot exist. Materialism directly contrasts with idealism, according to which consciousness is the fundamental substance of nature.
For other materialist theories, see Materialism (disambiguation).
Materialism is closely related to physicalism—the view that all that exists is ultimately physical. Philosophical physicalism has evolved from materialism with the theories of the physical sciences to incorporate more sophisticated notions of physicality than mere ordinary matter (e.g. spacetime, physical energies and forces, and exotic matter). Thus, some prefer the term physicalism to materialism, while others use the terms as if they were synonymous.
Discoveries of neural correlates between consciousness and the brain are taken as empirical support for materialism, but some philosophers of mind find that association fallacious or consider it compatible with non-materialist ideas.[1][2] Alternative philosophies opposed or alternative to materialism or physicalism include idealism, pluralism, dualism, panpsychism, and other forms of monism. Epicureanism is a philosophy of materialism from classical antiquity that was a major forerunner of modern science. Though ostensibly a deist, Epicurus affirmed the literal existence of the Greek gods in either some type of celestial "heaven" cognate from which they ruled the universe (if not on a literal Mount Olympus), and his philosophy promulgated atomism, while Platonism taught roughly the opposite, despite Plato's teaching of Zeus as God.
The nature and definition of matter—like other key concepts in science and philosophy—have occasioned much debate:[39]
One challenge to the conventional concept of matter as tangible "stuff" came with the rise of field physics in the 19th century. Relativity shows that matter and energy (including the spatially distributed energy of fields) are interchangeable. This enables the ontological view that energy is prima materia and matter is one of its forms. In contrast, the Standard Model of particle physics uses quantum field theory to describe all interactions. On this view it could be said that fields are prima materia and the energy is a property of the field.[43]
According to the dominant cosmological model, the Lambda-CDM model, less than 5% of the universe's energy density is made up of the "matter" the Standard Model describes, and most of the universe is composed of dark matter and dark energy, with little agreement among scientists about what these are made of.[44]
With the advent of quantum physics, some scientists believed the concept of matter had merely changed, while others believed the conventional position could no longer be maintained. Werner Heisenberg said: "The ontology of materialism rested upon the illusion that the kind of existence, the direct 'actuality' of the world around us, can be extrapolated into the atomic range. This extrapolation, however, is impossible...atoms are not things."[45]
The concept of matter has changed in response to new scientific discoveries. Thus materialism has no definite content independent of the particular theory of matter on which it is based. According to Noam Chomsky, any property can be considered material, if one defines matter such that it has that property.[46]
The philosophical materialist Gustavo Bueno uses a more precise term than matter, the stroma.[47]
Criticism and alternatives[edit]
From contemporary physicists[edit]
Rudolf Peierls, a physicist who played a major role in the Manhattan Project, rejected materialism: "The premise that you can describe in terms of physics the whole function of a human being ... including knowledge and consciousness, is untenable. There is still something missing."[50]
Erwin Schrödinger said, "Consciousness cannot be accounted for in physical terms. For consciousness is absolutely fundamental. It cannot be accounted for in terms of anything else."[51]
Werner Heisenberg wrote: "The ontology of materialism rested upon the illusion that the kind of existence, the direct 'actuality' of the world around us, can be extrapolated into the atomic range. This extrapolation, however, is impossible ... Atoms are not things."[52]