Greek Antiquity and the Modern Age: appearance and resurgence of mechanism
Materialism has developed in a mechanistic form since antiquity.
The Ionian philosophers of the school of Miletus – Thales, Anaximenes, Anaximander – seem to be the first materialist philosophers of Greek antiquity. They sought to account for all phenomena by a single principle, of a material nature: water with Thales, air with Anaximenes, matter, that is to say what is indefinite, with Anaximander. Following these materialist conceptions, a mechanistic materialism, or at least atomist, was constituted with Leucippus, Democritus, Epicurus, Lucretius. For these philosophers, all natural phenomena and the different bodies themselves are due to the movements and combinations of material atoms moving in a vacuum. The soul is then also a perishable material thing which differs from the body only by the special properties of its (lighter) atoms.
Much later, in the 17th century, this mechanistic materialism will be refined in mathematical language, more especially geometric, by Galileo, Gassendi, Hobbes. But the first, entirely occupied with physics, will not occupy himself with metaphysics, except to ridicule dogmatism; while Gassendi, a phenomenalist, will rather seek to understand how atoms and the void could account for the imagination; the last, Hobbes, will contribute to the advancement of materialist ideas as much by his moral philosophy as by his opposition to René Descartes. The design of the animal machine that he will propose is undeniably materialistic.
René Descartes will adopt an original position, using a form of methodological atomism from his first writings, atomism which he will be careful not to confuse with materialist conceptions. He will eliminate the notion of matter in order to design a physics compatible with the mechanism, without running the risk of being suspected of referring to materialist theories. Descartes’ mechanism, however, is valid only for its physics, that is, for what concerns the material world, and not for what concerns the spiritual world, whose constituents — the “thoughts” — are immaterial. Since Descartes’ ontology is dualistic (he considers being to be made up of two substances, matter or, more exactly, extension, and spirit), it cannot be called “materialistic”. Gassendi, for whom matter, defined by impenetrability, is active, will propose a conception that has been called dynamic or dynamist materialism.
The 17th century thus saw the establishment of the concepts that would lead to materialism, although many of its protagonists could hardly be called materialists. Materialism, in germ, takes shape on the one hand as a possible extension of the mathematization of physics, brought back more especially to atomism and mechanism, on the other hand, and jointly, as the conception carrying within it the vitalism.
Enlightenment: development of materialist doctrines
In the 18th century, called the Age of Enlightenment, mechanistic materialism, nourished by the results of science, spread among scholars and philosophers of the time and was used as a weapon in the ideological struggle against religious dogmatism and influence of the Church on all aspects of life in society. The philosophical authors who have committed themselves in this direction are in particular: La Mettrie (the first philosopher to have generalized to man the Cartesian thesis of the animal-machine, in his work L’Homme Machine, 1747), Diderot, d ‘Holbach, Helvetius, Cabanis.
From a metaphysical and cosmological point of view, these authors insist on the unity of the world, which is a material unity, and on the constancy of the quantity of movement on the scale of the universe, constancy which is the principle of mechanistic explanation of the world.
From the psychological point of view, the major thesis of eighteenth-century materialism is that matter itself is capable of thinking, when at least it is organized and structured for this purpose. This thesis refers in particular to Locke, as Voltaire popularized it, from passages where Locke questioned Cartesian dualism in the name of the omnipotence of God, who could very well have endowed matter with the property of think. From this theological hypothesis, opening up a simple theoretical possibility, we passed during the eighteenth century to an empiricist conception of thought, intended to justify the fact that our so-called “states of mind” are nothing other than of our brain. Indeed, medical observations tend to establish the rigorous correlation of mental phenomena and organic processes, those of the brain in particular.
19th century: naturalistic materialism and historical materialism
During the 18th century, the Cartesian type mechanism – the living being modeled by a machine – encountered many objections which showed the limits of this model. The age of the mechanism was indeed that of clocks and automatons, machines characterized essentially by their ability to perform movements independently. However, living organisms and human beings have many other characteristics that have had to be accounted for.
On the one hand, 19th century materialism continued the work of 18th century materialists in light of the advances in science of the time, with Charles Darwin and Claude Bernard as leading figures. On the other hand, it expressed itself in an unprecedented form that was based on a theory of history and society. Marxism was the outcome.
Thus we can speak of a double movement or two currents of nineteenth-century materialism: one naturalist and mechanistic, the other historical and dialectical. These two currents of thought, which still remain imbued with metaphysical dross, have in common to found the unity of matter and spirit on the question of the (material) origin of what we designate as spirit or thought.
All of the advances in the natural sciences combine to justify a fundamental conviction of naturalistic materialism: the gradual and necessary passage from the inert to the living.
The Darwinian theory of evolution brings to the materialist thesis of the physical unity of the world three weighty arguments:
- The unity of the living is no longer a mystery that would require presupposing some superior intelligence in order to think about its order. It is enough to understand that living beings all have common ancestors.
- The physical adaptation of living organisms appears as the unintended result of purely physical causality.
- The human being is only one of the products of evolution and not a divine creation. He must be integrated into the animal kingdom and not identified with the image of God.
The Darwinian theory of evolution thus provides the overall framework for the birth and evolution of living organisms, including human beings, while physiology or biology must make it possible to elucidate the mechanism leading to the appearance of organisms. (mechanisms of reproduction, genotype variation, etc.).
The concept of evolution becomes for naturalistic materialism an essential concept which gives its validity to monism (one of the main theses of materialism) by showing the unity of the human being and the living as well as that of the living and the ‘inorganic. This unity is a continuum that must be considered over a long time scale. Ludwig Büchner (1869) sums it up this way:
“The whole great mystery of being, and especially of organized being, consists in slow and gradual development.”
The scientific turn of materialism
According to the physicist Arthur Eddington (1929), the new scientific conception of the world, based on atomic physics, challenges our ordinary conception of the world.
We must therefore opt for a new form of materialism, more in line with current scientific data. For Eddington, our ordinary concept of a “table,” for example—that the table is a stable, solid object—is incompatible with its scientific equivalent, which describes a collection of moving particles in essentially empty space. Also ordinary concepts and scientific concepts cannot be jointly true of the same object. One must choose: Eddington chooses scientific concepts and forgoes ordinary concepts.
It is this ontological choice that will be made in the “Anglo-Saxon” countries (we will then speak after Quine of “ontological commitment”) and which will distinguish the materialism of these countries from the more traditional forms of materialism present on the European continent.
The revival of reductionist materialism
Materialism has experienced a particular development in the United States and English-speaking countries since the 1950s. The reductionist “mind-brain” thesis, which asserts the identity of nature between psychological (“subjective”) cerebral states or processes (psychophysical identity), is at the center of debates in philosophy of mind, and has brought to light the link between materialism and scientism.
During the first half of the 20th century, logical empiricism, very critical of the metaphysical theses of materialism, succeeded in imposing itself in countries with an empiricist tradition to become a sort of paradigm within which most thoughts on the relationship between body and mind. It is in this context that behaviorism developed.
Following the failure of the behaviorist program to explain the notion of mind, the problem of body and mind was posed in new terms in the context of an attempt to “naturalize” the spirit, inspired by the model of the natural sciences. The theory of mind-brain identity, or “central state materialism”, then emerged as a first alternative to behaviorism. This theory was initially championed by philosophers from the “Australian school” of philosophy – Ullin Place, Herbert Feigl, John Smart and David Armstrong among others. Smart, in particular, wrote an article entitled “Sensations and Brain Processes” published in 1959 in the Philosophical Review, which is one of its clearest formulations. For these materialist philosophers, the mind is the brain (hence the term “central state” materialism to distinguish it from theories associating the mind with the entire nervous system). Specifically, psychological states are neurological states.
This materialism is inspired by the model of scientific reductions leading to numerous assertions of identity. According to this model, water is identified with its molecular properties (water = H2O), genes with DNA sequences (gene = DNA), etc. Like these scientific identities, the reduction of mental states to brain states does not establish a logical equivalence between them (as between the word “gene” and its classic definition of “biological factor of heredity”): rather, it postulates an ontological (or metaphysical) identity, which explains the close link observed between them. This theory of identity therefore bets that there can be a successful translation of ordinary psychological discourse into that of physics or biology. It should be possible to translate terms like “desire”, “belief”, “pain” etc. in the vocabulary of science, which only refers to physical entities. The problem of body and mind would thus find a materialist solution in this inter-theoretical translation or reduction which should make it possible to “explain” psychological states by physical states.
Faced with the difficulty of making such identifications or reductions, both in scientific practice and at a more conceptual level (mental states do not “match” brain states), a radical form of materialism has been advocated. from the 1960s by authors such as Paul Feyerabend, Richard Rorty, Paul and Patricia Churchland: this is eliminativist materialism (or “eliminativism”). According to the supporters of this assumed and asserted scientism, the psychological vocabulary as well as the concepts and generalizations elaborated from this vocabulary are intended, not to be identified or reduced according to the scientific model, but to be purely and simply replaced (or eliminated). They would indeed constitute a naive form of psychology (folk psychology) which, like the old naive cosmology (astrological) or the old naive biology (animist or vitalist), is a failing theory which will eventually give way to a viable sciencific theory.
In the eyes of the Churchlands in particular, it is the neurosciences that can provide the appropriate theoretical framework for explaining behavior.
Materialism and the computer model
It was also to avoid the difficulties of the mind-brain identity theory that Hilary Putnam and Jerry Fodor proposed the functionalist theory of mind (or “computationalism”). But, unlike the eliminativist approach to the mind, this new theory of mental states recognizes their reality, and, unlike reductionist materialism, it also recognizes their specificity. This theory is inspired by the computer model: the mind can be considered by analogy with the software or program of a computer. In other words, the mind would be to the brain what software is to hardware.
A computer program is not made up of atoms, but it does have a physical existence. It corresponds to a particular level of description of the operation of the computer which must be described formally in terms of symbols and functions rather than in terms of wiring or electrical circuits. Similarly, there are two types of possible descriptions associated with human behavior: the physical description of the internal states of the brain (what happens neurologically when we do something) and the description of mental processes in terms of of symbols and functions.
The functionalist is therefore a materialist: for him, a human thought is basically nothing but the electro-chemical activation of a network of neurons. But just as one can design a computer program without mentioning the electronic circuitry that runs it, one can describe human psychology without mentioning what goes on in the brain, using only the common vocabulary and concepts of psychology. This can be translated and developed into a formal language: the “language of thought”.
The difference between the mind and the brain would thus correspond to a difference in the way of describing the same physical phenomenon, and not to a difference between two types of things.
The French philosopher Michel Onfray claims to adhere to a hedonistic materialism, “associating as much a wisdom of pleasure with disillusionment and a sense of death”.
Since the work of the Argentine “philosopher-scientist” and historian of ideas Mario Bunge, materialism – which asserts itself in his country as evolutionist, organicist, emergentist, biological and systemist – has diversified. But it is Mario Bunge’s conception of materialism that is supported today by Marc Silberstein, who states that “materialism is effective if it has the following attributes: if it is monist, realist, scientific, emergentist and systemist, reductionist as to objects, entities and processes of the world but not eliminativist as to properties.”