The Mechanical Philosophy


In this essay I want to draw attention to a period in the history of science that, I believe, will be of interest to supporters of Austrian economics. The episode in question is almost unknown to those only familiar with the accounts of scientific history found in works intended for the general public or in science textbooks, because it doesn't fit into the storyline such narratives almost invariably are intended to convey.

Murray Rothbard called that common tale the "Whig history of science," but it also might be termed the Voltarian or the Enlightenment history of science. It was spun in the wake of the triumph of Newtonian mechanics during the 18th century, by intellectuals eager to inspire reverence for the new natural philosophy they admired and to discredit the Catholic Church they despised. According to their account, after the decline of ancient Greek civilization, science had sunk from view beneath the dogmatism and superstition of the time they tendentiously called "The Middle Ages." (See Grant, 1996, for a debunking of this view.)

Only with the work of Copernicus, in the 16th century, did the light of reason again begin to shine through those clouds of ignorance. At the turn of the 17th century the clouds were further parted by Galileo and Kepler, and several decades later they were finally burned away completely by the brilliance of Newton. Once science had been liberated from the shackles of faith, its progress was steady and irresistible. The problem is that, in order to tell the story they wished to promote, the tellers had to edit out large portions of the actual history of science. One of the significant omissions is the fact that what was called "the mechanical philosophy" dominated science during most of the 17th century.

It is important for our purposes to understand that the mechanical philosophy, whose adherents included Descartes, Gassendi, Boyle, Hobbes, and other major thinkers, was put forward as a progressive program, seeking to banish "occult explanations" from acceptable scientific discourse. Although it took on somewhat different forms in the writings of its various proponents, it can be summarized, without too much distortion, as asserting that only the extension, place, and motion of bits of matter are valid components of a truly scientific explanation (Westfall, 1977, p. 31). The mechanical philosophers held that "bodies comprise only particles of matter in motion," where matter is forbidden from having any active principles (Westfall, 1977, p. 33). Or, to directly quote Descartes, who was perhaps the foremost promoter of the approach under discussion, "I considered in general all the clear and distinct notions which our understanding can contain with regard to material things. And I found no others except for the notions we have of shapes, sizes and motions . . ." (quoted in Sargent, 1995, p. 32).

A notable aspect of the mechanical philosophy, especially for our purposes, was its adherents obsession with creating models that could account for observed phenomena employing only the size, shape, and motion of material particles. Little was done in the way of ascertaining whether the models were realistic; the important thing was to have a model. For instance, magnetism was a thorny issue for these thinkers, since the most obvious explanation of magnetic attraction involved the occult and unacceptable notion of an attractive force. Descartes devised a suitably mechanical model attempting to account for magnetic attraction, one in which the Earth and other magnetic bodies emitted streams of little screw-shaped particles, which, when they passed through the pores of any iron object, drew that object towards the magnet. (See the image of Descartes' model at the top of this page, which is from the cover of Westfall, 1977.)

Along the same lines, "In De Corpore [Thomas] Hobbes had presented a mechanical explanation of the production of cold and ice, both of which he attributed to a 'constant wind' that pressed upon bodies." A liquid freezes when that wind "raises the parts of it in such a way that the uppermost parts become pressed together and thus 'coagulated'" (Sargent, 1995, pp. 202–03). And Robert Boyle and Robert Hooke explained the relationship they had discovered, between the volume of a certain amount of air and the pressure to which it was subjected, by "the supposition that air consists of particles like little coiledsprings, like wool, which 'consists of many slender and flexible hairs; e ach of which may indeed, like a little spring, be easily bent and rolled up, but will also, like a spring, be still endeavouring to stretch itself out again'" (Pyle, 1995, p. 476). Such models seem absurd to us today. But it is important to realize that, at the time they were put forward, they were seen as the cutting edge of science, replacing the primitive and unscientific explanations of natural phenomena that had been offered by Aristotle and his disciples.

Even in physics, where the mechanical philosophy was most successful, dogmatic adherence to its precepts crippled research into certain topics. For example, as Westfall notes: "By the end of the 17th century, the mechanical philosophy, which encouraged optics early in the century, and which furnished the idiom in which all students of optics . . . discussed the science, had become an obstacle to further progress. . . . [O]ptics stagnated for a century" (1977, p. 64).

In other sciences the effect of its supremacy were even more deleterious. Westfall describes "the story of chemistry in the second half of the [17th] century [as] the story . . . of its subjection to the mechanical philosophy, since the growing role of mechanisms in chemical literature appears less to have sprung from the phenomena than to have been imposed on them by external considerations" (1977, p. 69). Similar to the way in which model building in modern economics has been used to justify every conceivable policy prescription, Westfall notes: "The mechanical philosophy did not in itself offer a chemical theory. On the contrary, it was potentially adaptable to almost any theory" (1977, p. 71).

Rather than searching for the fundamental causal factors underlying the multiplicity of chemical phenomena, the focus of the mechanical philosophers was on devising some model, any model, that appeared to explain each particular phenomenon with which they were presented using only mechanical elements. Westfall comments, "Like his fellow mechanical chemists, [Lemery, the leading French chemist of the 17th century,] seemed possessed by a mania to explain every property and every phenomenon" (1977, p. 73). He contends, "In no area of science was the tendency to imagine invisible mechanisms carried to such extremes" as it was in chemistry (1977, p. 81). For example, Lemery's theory of why acids dissolved metals suggested that the particles making up acids had little, dagger-like points, points which skewered the smooth particles composing metals and then carried them away from their comrades. Metals could be precipitated back out of a solution by adding another substance whose particles moved in such an agitated fashion that they would break off the points of the particles of acid, thus setting the particles of metal free.

The most prominent, and arguably the best, chemist of the 17th century was Robert Boyle. Although he was not as dogmatic as many other proponents of the mechanical philosophy, it was still the case that "the development of a satisfactory chemical theory as such was not Boyle's goal. Chemistry represented to him a means to demonstrate the validity of the mechanical philosophy of nature" (Westfall, 1977, p. 77). Indeed, "his mechanical philosophy appears to have operated to thwart the most promising aspect of his chemistry" (Westfall, 1977, p. 79).

Westfall concludes his discussion of mechanical chemistry by saying: "Since there were no criteria by which to judge the superiority of one imagined mechanism over another, the mechanical philosophy itself dissolved into as many versions as there were chemists. . . . It is difficult to see that the mechanical philosophy contributed anything to the progress of chemistry as a science" (p. 81).

The reign of the mechanical philosophy had a similar effect on the advancement of biology. One of the most significant biological discoveries of the era, that the heart is a pump serving to circulate blood throughout the body, was made not by a mechanical philosopher but by an animist, William Harvey. (Descartes, instead, explained the heart as a heat engine that expanded the blood, forcing it out through the circulatory system.) The mechanists, when confronted with the discovery of mammalian eggs by investigators employing the microscope, and unable to accept the existence of anything such as a "formative virtue" that could transform some simple substance into a complex body, responded with the theory that a fully formed animal was contained inside every egg. Of course, if the little critter in the egg was a female, she would already have eggs in her, within which would be her fully formed children, who would contain eggs containing their children. . . . It even was suggested "that the entire human race was present already in Eve" (Westfall, 1977, p. 100).

In arriving at such theories, the mechanical philosophers had not engaged in any deep contemplation of biology, as a result of which they concluded that their method offered the best approach for examining living creatures. They had already decided that only mechanical explanations could qualify as scientific, and so they tried to force fit biological processes into their moulds. As Westfall puts it, "[Mechanistic biology] did not arise from the demands of biological study; it was far more the puppet regime set up by the mechanical philosophy's invasion" (1977, p. 104).

The mechanical philosophy lost its hold on the scientific imagination during the 18th century, due both to the unsatisfactory nature of many of the explanations it offered, and to the stellar success of Newton's distinctly non-mechanical theory of gravity. It is worth noting that in many cases, science advanced by going "backwards" to concepts that had been rejected by the mechanical philosophers as "unscientific." As I just noted, Newton's theory of gravity did not meet the mechanical criteria for a proper scientific theory—per Newton, one body was somehow able to influence another body without any physical contact between the two—and when it was published, it was widely derided by Cartesians as a throwback to the positing of "occult forces" characteristic of the superstitious views of Renaissance naturalism. Similarly, Newton attributed his mathematical advances to revisiting the works of the ancient Greek geometers, and dismissed the recently developed Cartesian geometry as "the Analysis of the Bunglers in Mathematicks" (Westfall, 1980, p. 379–80). Furthermore, some theories developed during the reign of mechanical philosophy, that were long rejected as hopelessly flawed, eventually underwent resuscitation. Again turning to Newton for an example, his idea that all material bodies are composed of only a very few elementary particles, and that what appear to be chemical elements are really compounds of those building blocks, and, therefore, could be transformed into each other, was seen as an unsightly blemish on his great career for two centuries. However, as Pyle notes:

This criticism seems unfair and unwarranted. In the first place, the Newtonian matter-theory is remarkably close to what we now believe to be the truth. Chemical species do only arise at a 'molecular' level, i.e. as a result of the aggregation of simpler (and chemical neutral) constituents. The chemical atom of Dalton is a highly complex structure, made up of neutrons, protons, electrons, etc., held together by powerful interparticulate forces of various kinds. The transmutation of the so-called 'chemical elements' is physically possible although, as Newton foresaw, highly difficult owing to the strength of those forces (1995, p. 433).

Although the mechanical philosophy is long dead and buried, our age is not without its own dogma regarding properly scientific explanations. Today, the prevailing belief is that any real science must be composed of mathematical models, models which yield quantitative predictions about some class of events based on particular, initial conditions, also specified numerically. Once again, the currently popular methodology has been imposed on diverse disciplines with little regard to whether it is suitable to their subject matter, but simply because it is thought to be the only respectable way to do science. The philosopher John Dupré calls this "scientific imperialism," meaning "the tendency for a successful scientific idea to be applied far beyond its original home, and generally with decreasing success the more its application is expanded" (2001, p. 16). Once again, we see a frantic effort to generate models fitting the accepted paradigm, with little regard for the realism of the assumptions and mechanisms from which they are constructed.

At this point, the relevance of the history of the mechanical philosophy to the circumstances with which Austrian economists currently struggle should be apparent. It illustrates a number of points that can be used to defend their embrace of an unfashionable view of economics:

It is not the case that science always makes steady progress; it sometimes enters cul-de-sacs that it must eventually back out of in order to move forward again. That is especially the case when a methodology from one science is imposed on another without concern for its aptness in the new domain.

It is not the case that scientific truth can be decided by a "market test"; science is not toothpaste, and markets cater to the preferences of participants, without regard to whether those preferences arise from scrupulous examination or ill-considered prejudice.

It is not the case that a real science must forget its founders; often, the key needed to unlock some gate barring the way forward can be found in the ideas of a long-dead thinker.

And it is not the case that scientists should placidly drift with the prevalent methodological tide like so many jellyfish bobbing in the waves; the greatest scientists have often been the ones who had the courage to swim against the current.


This piece was first published at Mises.org: https://mises.org/library/scientism-standing-way-science-historical-precedent-austrian-economics.