Materialism

Before 20th-century science discovered the subatomic world, the quantum world and its characteristic indeterminancy, chaos, emergence, and the full flowering of the world of fields, materialism, often called 'scientific materialism', served as a world view that attributed to matter the status as the underlying constituent of nature, matter as material particles, indivisible, in motion in a void, the interactions of the particles, dictated by necessities external to the particles, determining the shape, size, weight, and motion of all objects in the natural world.

Alternately, materialists imagined matter as elements, or elementary substances, such as earth (solid), air (gaseous), water (fluid), and fire (heat), substances distinguished by their 'qualities', qualities evident to sense experience, substances interacting through inherent properties, love (attraction) and strife (repulsion), whose consequences generated and decomposed all the objects of sense experience, clay and trees, sun, moon, and stars (Anastopoulos 2008)

Macmillan's Encyclopedia of Philosophy (2006) gives this definition of materialism:

Materialism is the name given to a family of doctrines concerning the nature of the world that give to matter a primary position and accord to mind (or spirit) a secondary, dependent reality or even none at all. Extreme materialism asserts that the real world is spatiotemporal and consists of material things and nothing else, with two important qualifications: first, space and time, or space-time, must also be included if these are realities rather than mere systems of relations, for they are not material things in any straightforward sense. Second, materialism is fundamentally a doctrine concerning the character of the concrete natural world we inhabit, and it is probably best to set to one side controversies over abstract entities such as numbers, or geometric figures, or the relations of entailment and contradiction studied in logic.

Note that the Macmillan encyclopedia's definition includes space and time as fundamental constituents of the world, even though "they are not material things in any straightforward sense".

The Routledge Encyclopedia of Philosophy (1998) defines materialism:

Materialism is the genera! theory that the ultimate constituents of reality are material or physical bodies, elements or processes. It is a form of monism in that it holds that everything in existence is reducible to what is material or physical in nature. It is opposed to dualistic theories which claim that body and mind are distinct, and directly antithetical to a philosophical idealism that denies the existence of matter. It is hostile to abstract objects, if these are viewed as more than just a manner of speaking...

Note that the Routledge encyclopedia's definition includes the word "processes", in a context that implies "processes" as "material or physical in nature".

Boyd et al. (1991), in the glossary of their Philosophy of Science, define materialism:

Materialism: The ontological doctrine that states that everything that exists is, or depends on, matter.

Materialism originated with the ancient Greek atomists and elementists of the 7th to 5th centuries BCE, and re-emerged and flourished as the scientific paradigm for explaining the nature of the universe for three centuries following the time of Isaac Newton (1642-1727). Newtonian and post-Newtonian materialism excluded any explanations of reality that could not be reduced to the physics of the time, whether the fundamental components required to account for the interactions or qualities of matter themselves qualified as material &mdash; as remains the case today among 21st century scientific materialists.

Materialism denied supernaturalism, in that it denied that material-independent spiritual or divine powers ever account for observable events in the natural. It denied mind as independent of, or fundamentally different from the body, an entity of interacting material substances. Such "classical" materialism held that natural interactions of matter always explain events, even in instances where lack of knowledge precluded explanation (Joad 2005).

Materialism affirmed determinism, in that it asserted that all events of the world result from preceding ones &mdash; embracing causality &mdash; and it asserted that knowledge of the state of the world at any given time can in principle enable prediction of the state of the world at a future time.

As originally formulated, materialism is a philosophy of mechanism and determinism in respect of workings of the natural world, the world as essentially a machine, a 'clockwork universe'.

Outmoded paradigm
Philosopher Jessica Wilson emphasizes that materialism, as originally formulated, is no longer a viable philosophy (Wilson 2006):

Materialism, roughly formulated, is the thesis that all broadly scientific entities are nothing over and above material entities, where the latter are characterized as being extended, impenetrable, conserved, such as to (only) deterministically interact, and so on. The material entities ultimately supposed to serve as an ontological basis for all else are those existing at relatively low orders of constitutional complexity – entities that are, as I’ll put it, ‘‘relatively fundamental’’. But contemporary physics has reported that the relatively fundamental entities have few, if any, of the characteristics of the material; and thus materialism has been rendered a has-been (Wilson 2006)

Physicists and science popularizers agree, proclaiming "Materialism is dead" (Davies and Gribbin 1992, 2007):

An extension of the quantum theory, known as quantum field theory…paints a picture in which solid matter dissolves away, to be replaced by weird excitations and vibrations of invisible field energy. In this theory, little distinction remains between material substance and apparently empty space, which itself seethes with ephemeral quantum activity. The culmination of these ideas is the so-called superstring theory, which seeks to unite space, time and matter, and to build all of them from the vibrations of submicroscopic loops of invisible string inhabiting a ten-dimensional imaginary universe. ...scientists are increasingly thinking of the physical Universe less as a collection of cogs in a machine and more as an information-processing system. Gone are the clodlike lumps of matter, to be replaced instead by "bits" of information. This is the shape of the emerging universe paradigm—a complex system in which mind, intelligence and information are more important than the hardware.

Philosopher Alexander Rosenberg (2005) echos those views, speaking to materialism's deterministic aspect:

Between them, Newton and Darwin are the great sources of philosophical materialism or physicalism, which undermines so much traditional philosophical theory in metaphysics, the philosophy of mind, and for that matter may threaten moral philosophy...But, twentieth-century developments in physics and the foundations of mathematics have shaken the confidence of philosophical materialism far more than any merely philosophical arguments. First, the attempt to extend deterministic physical theory from observable phenomena to unobservable processes came up against the appearance of sub-atomic indeterminism in nature. It has turned out that at the level of quantum processes - the behavior of electrons, protons, neutrons, the photons of which light is composed, alpha, beta and gamma radiation - there are no exceptionless laws, the laws seem to be ineliminably indeterministic.

Relation to 'physicalism'
...in progress