The Mechanization of “Force”

49,421 characters2008.12.12

Force = mechanics? — Raising the question

Scholars often say: the Scientific Revolution was accompanied by (or led to) the “mechanization of the world picture.” We are also told that this so-called “mechanization” means “mechanization into mechanics,” which means “mathematization,” which means “quantification”…

It is indeed the case that in modern Western languages mechanics and machinery are the same word (mechanics), and that the modern “mechanical world” is indeed mathematized, while mathematization does indeed imply quantification—that is, the flattening of singularity and quality, and the “disenchantment” of the world.

However, once we trace this situation back into history, the matter is by no means so simple—the above-mentioned “equal signs” are each and every one suspicious! In history we find: mechanization does not necessarily mean mechanization into mechanics, and mechanization into mechanics does not necessarily mean mathematization; nor is the center of mathematics necessarily quantity and calculation…

So we cannot help but ask: when, how, and by what means did the unity of these concepts become possible in the first place?

Clearly, whether in Chinese or in Western languages, “force” (vis / force) and “machine” have never been the same thing; these two concepts are neither synonymous nor of the same origin. And yet how is it that “mechanics” and “machinery” have quite naturally come to be the same concept? Something wondrous and important must have happened here,

This article attempts a rough examination of this historical transformation of concepts. The question of this article is: how did the mechanization of “force,” or rather the fusion of the concept of “force” with mechanism, come about? And what does this mean?

Before tracing the history, let us first review the concept of “force” in modern physics.

A very popular and widely praised introductory physics textbook of our time writes:

In the previous chapter the word force was used as a synonym for “external influence”; now we need a specific definition…. Since the law of inertia tells us that objects not acted on by external influences move with nonaccelerated motion, it is natural to define force as the external influence that causes an object to accelerate.[①]

The author then offers some further clarification:

There are many misconceptions about the term force. Like the word push, force is an action, not a thing; an object cannot be a force, nor can it have force. Force is something one object does to another, like “pushing”; one object can “exert a force” on another object.[②]

…Notice that a moving ball does not have force; that is to say, it does not “carry force with it.” A force is like a push; you cannot say that a ball “has a push.”[③]

In short, force is “an external influence that does not belong to the object itself and causes the object to accelerate.” Such an understanding—as the following discussion will suggest—was by no means always there; it is precisely a hallmark consequence of modern science. It was from Newton onward that the concept of “force” in this sense was established, and it was precisely this establishment that made possible the modern “mechanical view of nature.”

Force = cause — tracing it back to its source

Although the foregoing definition is highly “modern,” the analogy it borrows is quite “primitive”—namely, understanding “force” through “pushing.” From antiquity to the present, this has probably been the most intuitive and basic way of understanding the word “force.” Whether in “strength,” “vital force,” or the “force” in “pressure” and “impulse,” it seems that we obtain our intuitive understanding of these concepts from actions like “pushing.”

This notion of “pushing” is no small matter—it is also the original intuition behind the concept of “cause.” In fact, we shall find that the reason the transformation of the concept of “force” is so significant lies precisely in the tangled connection between “force” and “cause.”

Like keywords of science such as “cause” and “law,” “cause” originated as a concept in social activity, especially legal activity—“In Greek, the word used for cause actually entered the vocabulary of science and philosophy from legal language…. In its legal usage, the word originally referred to the locus of responsibility. A lawsuit is always brought about by some action; …”[④] In litigation, asking for the “cause” of a matter involves two basic meanings: the immediate agent and its motive. For example, the direct answer to “Why was A injured?” may be “B hit him,” while a further answer to “Why did B hit him?” may be “B hit him in order to rob money.” These two correspond exactly to Aristotle’s efficient cause and final cause, and are the most original understanding of the word “cause.” And as we shall see, because the mechanization of “force” brought about the mechanization of “cause”—that is, the complete elimination of anthropomorphic elements—so that in the modern world efficient and final causes find nowhere to reside, this is a matter for later.

For Aristotle, the “efficient cause,” or “mover,” “refers to the source that brings about motion and change,”[⑤] and “is the origin or cause of motion.”[⑥]

Kuhn noticed the importance of the notion of “cause” and its transformations in the development of science. Quoting Piaget, Kuhn first distinguished the concept of cause: “We must consider the concept of cause under two headings, the narrow and the broad. I think the narrow concept originally came from the egocentric idea of an active agent, a man who pushes or pulls, emits a force or displays dynamism. It is very close to Aristotle’s concept of efficient cause, a concept that first played a significant role in technical physics in the seventeenth century when the problem of collision was analyzed.”[⑦] The broad concept of cause, by contrast, refers to “the general concept of explanation”; for modern science, this means explaining a given event by means of a set of temporally prior events and a set of relevant natural laws through deductive inference, where the explanans is therefore the cause and the explanandum the effect (as depicted, for example, by the D-N model in philosophy of science).

Kuhn pointed out: “Although the narrow concept of cause was once an extremely important part of seventeenth- and eighteenth-century physics, its importance declined in the nineteenth century and had almost completely disappeared in the twentieth.”[⑧]

What exactly happened here? The following will attempt to suggest: in the transformation of the concept of cause, Newton’s significance was decisive. It was Newton who brought “dynamics,” that is, the narrow concept of cause, to its highest point in science, and the price paid was precisely the complete elimination of that concept itself!

Of course, before Newton, the pioneers of modern science had already undertaken various reexaminations and transformations of concepts such as causality. Burtt mentions that Kepler “had already arrived at a new concept of causality, that is to say, he regarded the fundamental mathematical harmony discoverable in the observed facts as the cause of those facts, as, in his usual way of speaking, the reason why these facts are as they are.”[⑨] But as Burtt immediately says: “this concept of causality is actually Aristotle’s formal cause reinterpreted in accordance with rigorous mathematics”[⑩]. In other words, what Kepler did was nothing more than place greater emphasis on the search for formal cause than on efficient cause, and did not fundamentally change people’s understanding of efficient cause; moreover, Kepler’s idea was based on belief in the mathematical God, that is to say, mathematical harmony was the motive or purpose by which God created the world in this way.

Galileo, however, did “explicitly abandon the concept of final causality as an explanatory principle,” and also excluded efficient cause from the objects of scientific inquiry. “For Galileo, how motion occurs is the target of analysis, and this analysis is conducted by strict mathematical methods.”[11] In other words, Galileo held that science investigates only the “how” and not the “why.” But this merely means that for Galileo, “cause” could not be “mathematized”; yet at that time the mathematization of the entire world picture was far from complete, and excluding cause from mathematical analysis by no means meant denying or abolishing it. We will return to this question later—only after Newtonian mechanics would mathematics finally be able to swallow everything up.

In Descartes, we seem to find a formulation very close to modern mechanics: “The first law is that each thing, insofar as it is simple and undivided, will remain as far as possible in the same state in which it is, unless some external cause acts on it…. If it is at rest, then it will never begin to move unless some other cause impels it to motion. If it is in motion, and nothing else can obstruct it, then there is no reason to suppose that it will bring itself to a halt by its own power.”[12] Yet the “force” in Descartes, as the source of motion and change, is by no means the same concept as in Newtonian mechanics. Compared with the contemporary textbook quoted earlier, we can easily see Descartes’s “error”—namely, the belief that “force” is internal to the object, that a ball can “carry force with it” and transmit force to another ball! Descartes’s “force” is roughly equivalent to “momentum” in modern science. Precisely for this reason, Cartesian philosophy encountered greater difficulties in mathematization, and the mechanistic worldview represented by Descartes never ultimately became the so-called mechanical worldview. Related issues will be mentioned later.

Force = the supernatural — the fissures in the mechanistic world

Although Aristotle distinguished the four causes, in analyzing the motion of natural objects form, efficient cause, and final cause become united again; thus terms such as “motive” and “purpose” remain terms in the Aristotelian tradition of physics. One major contribution of the pioneers of the Scientific Revolution was to purge such anthropomorphic terms from science and replace them with mechanical or mathematical concepts. Burtt notes:

The way Aristotle and the scholastics analyzed motion on the earth, that is, “local” motion, aimed to answer the question of why motion occurs rather than how it occurs, and proceeded in terms of the entities involved in any given terrestrial motion. As a result, words and phrases such as action, passion, efficient cause, purpose, and natural place dominated their studies. As for motion itself, they said almost nothing, except to make some simple distinctions between natural motion and forced motion, between rectilinear motion and circular motion, and so on. The question of why motion occurs was the object of study, and this study was carried on in qualitative and substantial terms; for Galileo, however, how motion occurs was the target of analysis, and this analysis was conducted by strict mathematical methods.[13]

Burtt’s comment may not be entirely accurate. Zhang Butian’s excellent doctoral dissertation[14] points out that scholastic natural philosophy in the fourteenth century had already made important contributions to the quantification of “quality” and “motion.” But an important part of that contribution was precisely the “Oxford Calculators’” clear distinction between dynamics and kinematics, for example, “Swineshead explicitly distinguished measuring motion according to causes (motive force and resistance) and according to results (distance traversed over a period of time).”[15]

Whether scholastics, Galileo, or mechanists, the “mathematization,” “quantification,” or “mechanization” they carried out was aimed at “kinematics,” not “dynamics,” and the reason kinematics could be quantified or mechanized was precisely that it drew a clear boundary against dynamics. Only with Newton was a quantified and mechanized dynamics successfully established; in science before then, “force” was precisely that part of the world that could not be taken into metrology or mechanics—among the quantitative and mechanical world, the last remaining things not yet disenchantable, with “mystery” still able to hide in these fissures.,

Earlier I mentioned that Galileo excluded efficient cause from mathematized science, but by no means from the world! “In him, … atomic motion is treated only as a secondary cause of events, while the primary or basic cause is always conceived in terms of force.”[16] Of course, Galileo’s “force” was not the quantified force in Newton’s sense, but some kind of “vital force,” “strength,” or something else altogether—in any case, something non-mathematical and still enchanted.

Hobbes, by contrast, most thoroughly rejected efficient and final causes; with him, “causality always has to be explained in terms of the concrete motion of concrete bodies. For Galileo, that hidden tremendous power is the main cause or basic cause of the consequence, but in Hobbes it disappears…. ‘Except in a continuous, moving body, there cannot exist a cause of motion.’”[17] And Hobbes, as an extreme materialist, also happens to confirm this fact: at the time, rejection of “force” and rejection of “mystery” were in agreement.

Among the mechanistic philosophers, the word “force” was not in fact excluded from their physics; however, the “force” in their minds was always a different matter from Newton’s “force.” Westfall notes: “Huygens believed that mechanics was only the science of moving bodies interacting by collision. The concept of force appeared only in the context of circular motion, and in circular motion force did not represent an action on an object, but rather represented a tendency that the object possesses in motion. In this way it was similar to Descartes’s ‘force of bodily motion’ and approximated what we call momentum, a concept accepted by mechanistic philosophers.”[18] Leibniz is slightly different: “The ‘force’ used by Leibniz could easily be transformed into what we today call ‘kinetic energy.’ His natural philosophy differed greatly from Descartes’s, but it still accepted the premise that force is not something acting on bodies to change their state of motion, but something bodies possess.”[19]

How important is the difference between treating force as something an object possesses and treating it as the interaction between objects? Let us leave that question for later discussion. What we note here is this: whether quantified or not, this concept of internal vitality easily invites one to think of certain supernatural mysterious powers lurking behind it, or some kind of “hidden quality.” Even some mechanists themselves would make such associations; Westfall points out: “Clearly, for Leibniz, vis viva represented more than just a number. The intrinsic essence of things, namely vis viva, contained many supernatural meanings far beyond the scope of mechanics.”[20]

Mechanical theorists, too, could not help at first interpreting Newton’s “gravity” in terms of “the forces within bodies.” For in the mechanical theorists’ view, “vital force” after all works only through collision and contact and is transmitted through them; thus it does not yet seem all that mysterious. Newton’s “gravity,” by contrast, seemed able to act at a distance, which made it seem especially mysterious. Kuhn comments: “For most seventeenth-century corpuscularians, the concept of gravity as an innate principle of attraction seemed too much like Aristotle’s rejected ‘natural tendency’ to motion. The great virtue of Descartes’ system lay in the complete elimination of all such ‘occult qualities.’ Cartesian corpuscles are completely neutral, gravity itself is explained as the result of collisions; the idea of an innate principle of attraction at a distance seems a retreat into the mysterious ‘sympathies’ and ‘potencies’ that made medieval science so absurd. Newton himself fully agreed. He repeatedly tried to develop a mechanical explanation of attraction…”[21]

But Newton could absolutely not tolerate those mechanical hypotheses that left God with nothing to do. He believed that “the true, ultimate cause of gravity is the action of God’s ‘spirit.’”[22] Newton’s God is one who is always in action—not only as the “first mover,” but also as one who must keep moving this world at every moment. I would point out that this may have been the last “struggle” of the efficient cause: when Newton removed the “mover” from nature, he could only have the supernatural God take on this role, thereby preserving “cause” in God’s will. And once God’s work was found to be unnecessary, no other thing would ever again be qualified to serve as the “mover”; then the efficient cause, of course, would have nowhere left to be found. But that is a story for later.

At this point, we may be able to point out that the reason the mechanical science represented by Descartes failed to succeed was precisely that it was too radical and too ahead of its time: it too early and too decisively excluded the place of supernatural force from science, recognizing only a world picture composed of matter and motion—namely, a mechanical and mathematical world. But this hasty rejection of the concept of “force” greatly obstructed the advance of mathematization. The mechanical world was therefore never completed; mysterious and supernatural powers could always survive in the cracks. Newton, however, because of his more conservative religious beliefs and his more pronounced mystical tendencies, was more easily able to accept the concept of “force,” and thus made it possible to complete the mathematization of the world in one fell swoop. But in the process, since the concept of “force” was simultaneously disenchantized, the supernatural and the mysterious, in this world, could no longer find any place to live; after struggling for a while in God, they finally disappeared together with God’s departure.

Still, why is the concept of “force” so easily linked with the “supernatural” or the “mysterious”? Is it merely a coincidence, or merely because scientists initially failed to mathematize it successfully? Not at all. In fact, the connection between “force” and the “supernatural” or the “unnatural” is primordial. Let us recall the original meaning of “efficient cause”: in Aristotle, efficient cause was from the outset set in opposition to formal cause, the latter being used to explain the cause of objects that do not undergo motion or change, and the former the cause of motion and change. Considered in light of Aristotle’s natural philosophy: if a thing is in its natural place, that is, when it is unmoving and unchanged, then explaining it does not require appeal to efficient cause, or only requires appeal to its immanent efficient cause, which is at the same time the formal cause or final cause of this natural object; only when a thing is in a non-natural position does its behavior need to be explained by appealing to an external efficient cause—a mover. When we connect this with the etymology of the word “cause,” which comes from legal terminology, it becomes even easier to understand: only when the normal order has been disturbed do we ask after a responsible party. Thus from the very beginning “force” specifically referred to the explanation of “abnormal phenomena.” Kuhn also mentions this point: “As distinct from regularity, anomaly is explained by narrow sense causality. Once again the similarity of Aristotle’s physics is striking. Formal cause explains the order of nature, efficient cause its departures from order. But now irregularity, like regularity, is within the domain of physics.”[23] It is easy to imagine that when “force,” understood as a departure from order, is itself brought under “law,” even becoming the basis of all law, the boundary between irregularity and regularity disappears at once without a trace.

Force = Interaction—Newton’s Revolution

Since already in Aristotle the efficient cause and final cause of natural objects can both be subsumed under formal cause, then what is the significance of Newton’s reintegration of dynamis and form? Hadn’t Aristotle already done that?

As the saying goes, times change; by Newton’s era, “formal cause” had long since become something quite different from Aristotle’s version.

The ancient Greek cosmos was formally (essentially) heterogeneous, and hierarchically ordered. Every body had its proper natural place; when it deviated from that natural position, it possessed within itself a动力朝向 natural place, and through the “push” of this internal dynamis, the body would move toward its natural place as its “end.” In this way only could formal cause, efficient cause, and final cause be unified.

But when we turn to the universe of modern people, we find that this kind of unity can no longer be achieved—the concept of a natural place has been abolished, and the finite, heterogeneous cosmos has become the infinite, homogeneous Universe. Under these circumstances, even if you still endow bodies with an inner dynamis, where are they supposed to move? Aristotle’s cosmic form may offer a dynamical explanation for the motion of bodies, but the mechanical infinite universe cannot. To speak again of inner pushing, potentiality, dynamis, and the like in the new universe is bound to leave one “dizzy and disoriented,” because in this universe there is no “direction” to be found. Thus the Aristotelian sense of “dynamis” had no choice but to be excluded from kinematics.

However, what had to reject “dynamis” because of the infinite expansion of the universe was mainly kinematics, since it studies displacement in space. In fact, other phenomena could still be explained in the traditional way. Thus we find that even after Newton, traditional concepts such as “vital force,” “potentiality,” and “tendency,” which appeal to internal driving forces, remained active in discussions of phenomena outside kinematics such as electricity, magnetism, heat, and life—until Faraday and Maxwell invented the concept of the field and thereby reified “force,” at which point Aristotle’s “dynamis” was truly swept away.

Why was it that scholars before Newton failed to establish a new dynamics suited to the new universe, whereas Newton succeeded? Apart from factors such as timing and mathematical skill, Newton’s breakthrough lay in his replacement of the concept of “force” from beginning to end—a wholesale substitution, one might even say, of the concept itself!

First, what modern people often like to talk about is that, unlike Aristotle, who regarded force as the cause of motion, Newtonian mechanics regarded force as the cause of a change in velocity, and motion became a “state” of bodies rather than an action needing explanation. But, on the one hand, this change had already been accomplished before Newton by Galileo and others; on the other hand, this change is perhaps better understood less as a transformation in the concept of “force” than as a transformation in concepts such as “motion,” “change,” or “state” (though conceptual changes are always intertwined). Koyré says: “As long as motion was a process, it could not continue without a mover; only motion as a state requires no cause or mover.”[24] It was precisely through this transformation that Galileo excluded efficient cause from kinematics, but as noted above, this does not mean that the concept of dynamis was replaced, much less that it was driven entirely out of the world.

Second, Newton replaced the then-fashionable concept of an instantaneous action, the “impulse,” with a continuously acting force. Cohen notes: “In Newton’s time, the chief meaning of force was the impulsive action or instantaneous action produced when one body strikes another or is struck by another body. Such impact force was the subject studied intensively in the seventeenth century by Galileo, Borelli, Marcus Marci, Descartes, Wallis, Wren, and Huygens.”[25] And “in the Principia, the first proposition about motion expresses the transition from discontinuous impulse to continuous force.”[26] The concept of “impulse” was probably a result of the corpuscular philosophers’ fixed idea of “little spheres colliding with one another.” Newton’s breakthrough was undoubtedly meaningful. But on the one hand, among mechanical philosophers the concept of “force” was not limited to impulse alone; on the other hand, in Newton, the concept of “impulse” was not rejected either. Thanks to the invention of calculus, whether force actually acts as the sum of impulses or in the form of a continuous force, the mathematical treatment does not differ very much.

In sum, although the points mentioned above are indeed important contributions of Newton, their originality and breakthrough character do not seem especially obvious.

In fact, as historians of science had long since pointed out, among Newton’s three laws, “the third law is the one that is most original to Newton.”[27] If it were only the first two laws, then Newton’s contribution would amount to nothing more than a synthesis of his predecessors; only the invention of the third law makes it fully fitting that Newton should be called a revolutionary.

Newton’s third law:

To every action there is always an equal and opposite reaction; or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.[28]

This law looks so simple and self-evident—how much significance could it possibly have? Perhaps this is precisely the first formidable thing about it: it appears so natural, so unremarkable, that even in Newton’s own time, I suspect it would not have given readers any earth-shattering feeling at all (note that Newton’s view of space and time, calculus, the law of universal gravitation, and even the law of inertia, among others, all provoked wide and intense controversy at the time, yet one scarcely ever hears of anyone specifically directing their attack at the third law). Thus it was easily accepted without criticism—along with the major transformation implicit behind it.

Only the third law, for the first time, explicitly determines “force” as “interaction.” This concept, before Newton, and even in the definition of “external force” in the Principia, had never been made explicit!

Definition 4 of the Principia says: “An external force is an action exerted upon a body, in order to change its state, either of rest, or of uniform motion in a right line.”[29] People are more likely to focus on the latter half of this definition, namely that “uniform rectilinear motion” and “rest” are placed on the same level, both becoming states of a body, and this of course is the most important transformation. Yet we must also notice the first half of the sentence—in sharp contrast to the latter half, the first half invokes the most primitive line of thought: explaining “force” by means of “push.”

Why not use more neutral words such as “influence,” and instead employ the original, anthropomorphic concept of “push” to define “force”?[30] Would it not be better to delete “push” and simply say “action”?

In another place, Newton even declares that rather than regarding centripetal force as attraction, “it would perhaps be more accurate to call it repulsion.”[31] Elsewhere, Newton “uses ‘attraction’ and ‘repulsion’ simultaneously, and even gives priority to ‘attraction.’”[32] Koyré noticed the oddity here and thought: “This shows that, for Newton—as also for his mechanical opponents—repulsion was the only physically admissible mode of action of force, and he was himself perfectly aware of the danger implicit in using the term ‘attraction.’ Yet the danger is hardly less if one takes the word ‘repulsion’ at face value, for it implies a real, physical mechanism: that would be too submissive to Descartes. Newton therefore explains that, just like ‘attraction,’ we should not think that ‘repulsion’ implies some determinate physical meaning: both terms should be understood in a purely mathematical way…”[33] In Koyré’s view, “the consequence of Newton’s consistently treating attraction and repulsion in parallel” is that “this can only create the impression that in both cases he is dealing with similar physical forces, even if he disregards or abstracts away their physical reality and considers only the mathematical aspect.”[34]

Yet the difference between Newton’s “gravity” and the traditional “push” does not lie merely in the fact that the former is mathematical and the latter physical. A more important point is this: the former is neutral and indifferent, whereas the latter is anthropomorphic and directional. The former is “interaction,” whereas the latter is not!

When we speak of “pushing,” we will imagine one “pusher” and another “pushee,” and these two are by no means equal in status! The former is active and the latter passive; the former is also “prior” both temporally and logically. Aristotle explicitly notes the difference between the two: “In sum, teaching and learning, or acting and being acted upon (the active and the passive, the pushing and the pushed), are not altogether the same, but the thing in virtue of which they exist—motion—is the same. For the activity toward actualization of A in B and of B through the action of A are not the same in definition.”[35]

For Descartes, the asymmetry of “pushing” is still very clear: “When one body pushes another body, it cannot communicate any motion to the other body unless it simultaneously loses as much motion as it communicates; nor can it take any motion from the other without simultaneously acquiring as much from it. … We observe that a body begins to move or ceases to move because it is pushed or impeded by other bodies.”[36] It is probably precisely this fixed idea that pusher and pushee occupy unequal positions that led Descartes to such astonishingly mistaken conclusions as: “when one body encounters another [stronger than itself], it does not lose any motion; and when it encounters a weaker body, the motion it loses is exactly equal to what it transmits to the other.”[37]

When Newton turned “push” into “interaction,” all the residual power of efficient cause left over in “push” was driven out, and there was no hope of restoration! Why? The reason is simple—“causal relation” is an asymmetric relation! Even if we often say that two things “are mutually cause and effect,” this either refers to the mutual reinforcement between two long-term events that accompany each other, or it speaks of causality in two different senses (for example, on the one hand efficient cause, on the other hand final cause); it is impossible to say that two things are “mutually efficient causes.” Thus there is no efficient cause in the interaction of two things that are completely equal in temporal, logical, and ontological status. “Universal gravitation” is everywhere; all bodies at all times are pushing on one another in a wholly equal manner, without precedence or order—who then is the cause?

And it is the expulsion of efficient cause that is the crux of how “purpose” ultimately disappears from the modern world. The infinite expansion of space may have caused people to lose their bearings in the universe, but it did not yet fundamentally eliminate the possibility of anchoring “final cause.” The disappearance of efficient cause, however, is quite another matter! In the preceding discussion we saw that, in the most primordial sense, “final cause” seems to be the answer to a “second-order question” that depends on efficient cause—first ask, “Who did this?” and only then ask, “For what purpose did he do it?” But now efficient cause can no longer be found, and then final cause is not merely impossible to find; even asking about purpose itself becomes impossible!

Perhaps precisely because Newton himself had a dim awareness of certain serious consequences, he felt it necessary to let God continue to play the role of “pusher.” For with the establishment of the new way of thinking that “force = interaction,” relations among all natural things could no longer be unequal; natural things no longer had the standing to play the role of “pusher.” But in any case, God is always supernatural, after all, and he still retained the qualification to “push.”

Were the expulsion of “efficient cause,” or what Kuhn called the “narrow concept of cause,” from modern science and indeed from the whole modern world, ultimately a good thing or a bad thing? Is it right or wrong to deal with the question of causes by resorting to “scientific explanation”? These are matters on which I find it hard to pass judgment. Kuhn, however, surprisingly says: “In some sense revolutions in explanatory models can even be regressions.”[38] — not saying they are “incommensurable,” but directly saying “regressions”! In any case, this transformation of ideas was indeed of extraordinary significance—if the concept of “significance” still has significance.

References

[French] Alexandre Koyré: From the Closed World to the Infinite Universe, trans. Zhang Butian, Peking University Press, 2nd ed., 2008

[French] Alexandre Koyré: Newtonian Studies, trans. Zhang Butian, Peking University Press, 2003

[American] Thomas Kuhn: The Copernican Revolution, trans. Wu Guosheng, Zhang Donglin, Li Li, Peking University Press, 2003

[American] Thomas Kuhn: The Essential Tension, trans. Fan Dainian, Ji Shuli et al., Peking University Press, 2004

[American] Edwin Arthur Burtt: The Metaphysical Foundations of Modern Physical Science, trans. Xu Xiangdong, Peking University Press, 2003

[American] Richard S. Westfall: The Construction of Modern Science, trans. Peng Wanhua, Fudan University Press, 2000

[American] I. B. Cohen: The Newtonian Revolution, trans. Yan Feng, Gong Hongniu, Ouyang Guangming, proofread by Gu Luanling, Jiangxi Education Press, 1999

[Ancient Greek]: Aristotle: Physics, trans. Zhang Zhuming, Commercial Press, 1982

[American] Art Hobson: Physics: Concepts and Cultural Literacy, trans. Qin Kecheng, Liu Peisen, Zhou Guorong, Higher Education Press, 2008

Great Ideas of the West (Vol. 1), trans. Chen Jiaying et al., Huaxia Publishing House, 2008

Midnight, December 12, 2008

[①][American] Art Hobson: Physics: Concepts and Cultural Literacy (4th ed.), trans. Qin Kecheng, Liu Peisen, Zhou Guorong, Higher Education Press, 2008, p. 72

[②]Same as above

[③]Same as above, p. 73

[④]Great Ideas of the West (Vol. 1), trans. Chen Jiaying et al., Huaxia Publishing House, 2008, p. 120

[⑤][Ancient Greek]: Aristotle: Physics, trans. Zhang Zhuming, Commercial Press, 1982, p. 60, 198a15. By the way, the example Aristotle gives for efficient cause is: “Why did they go to war? The answer: because someone else attacked first.”

[⑥][Ancient Greek]: Aristotle: Physics, trans. Zhang Zhuming, Commercial Press, 1982, p. 72, 202a11

[⑦] [American] Thomas Kuhn: The Essential Tension, trans. Fan Dainian, Ji Shuli et al., Peking University Press, 2004, p. 21, p. 22

[⑧]Same as above, p. 26, p. 28

[⑨][American] Edwin Arthur Burtt: The Metaphysical Foundations of Modern Physical Science, trans. Xu Xiangdong, Peking University Press, 2003, p. 45, p. 64

[⑩][American] Edwin Arthur Burtt: The Metaphysical Foundations of Modern Physical Science, trans. Xu Xiangdong, Peking University Press, 2003, p. 45, p. 64

[11]Same as above, p. 69, p. 91

[12][French] Alexandre Koyré: Newtonian Studies, trans. Zhang Butian, Peking University Press, 2003, p. 79, p. 75. Owing to very limited time, energy, and ability, everything I have consulted and cited here is from Chinese translations of secondary literature. I did also look through a small number of Chinese translations of primary sources, but since they did not offer any obvious help to the overall conception and argument, I have not included them in the bibliography. Apart from the few quotations from the Principia, most references to early modern scientists are indirect citations from the corresponding secondary literature. Since I have not usually checked the original works, in the notes I will only indicate the source as it appears in the secondary literature, without further itemizing it.

[13][American] Edwin Arthur Burtt: The Metaphysical Foundations of Modern Physical Science, trans. Xu Xiangdong, Peking University Press, 2003, p. 69, p. 91

[14]Zhang Butian: “The Quantification of Qualities and the Quantification of Motion—A Preliminary Exploration of the Kinematics of 14th-Century Scholastic Natural Philosophy,” unpublished typescript

[15]See p. 80 of the above typescript

[16][American] Edwin Arthur Burtt: The Metaphysical Foundations of Modern Physical Science, trans. Xu Xiangdong, Peking University Press, 2003, p. 77, p. 99

[17]Same as above, p. 107, p. 133

[18] [American] Richard S. Westfall: The Construction of Modern Science—Mechanism and Mechanics, trans. Peng Wanhua, Fudan University Press, 2000, p. 141

[19]Same as above, p. 146

[20]Same as above, p. 145

[21] [American] Thomas Kuhn: The Copernican Revolution—Planetary Astronomy in the Development of Western Thought, trans. Wu Guosheng, Zhang Donglin, Li Li, Peking University Press, 2003, pp. 251–252, pp. 258–259

[22][French] Alexandre Koyré: From the Closed World to the Infinite Universe, trans. Zhang Butian, Peking University Press, 2nd ed., 2008, p. 212, p. 234

[23] [American] Thomas Kuhn: The Essential Tension, trans. Fan Dainian, Ji Shuli et al., Peking University Press, 2004, p. 26, p. 27

[24][French] Alexandre Koyré: Newtonian Studies, trans. Zhang Butian, Peking University Press, 2003, p. 71, p. 67

[25] [American] I. B. Cohen: The Newtonian Revolution, trans. Yan Feng, Gong Hongniu, Ouyang Guangming, proofread by Gu Luanling, Jiangxi Education Press, 1999, p. 186

[26]Same as above, pp. 189–190

[27]Same as above, p. 192

[28] [British] Newton: Mathematical Principles of Natural Philosophy, trans. Wang Kedi, proofread by Yuan Jiangyang, Peking University Press, 2006, p. 8

[29] [British] Newton: Mathematical Principles of Natural Philosophy, trans. Wang Kedi, proofread by Yuan Jiangyang, Peking University Press, 2006, p. 2

[30]In some other translations, the “pushing” here also seems to be rendered as “pressing.” I have not checked the original, so I cannot be sure. But in any case, this word is, first, anthropomorphic, and second, traditional. On that there is no doubt.

[31][French] Alexandre Koyré: Newtonian Studies, trans. Zhang Butian, Peking University Press, 2003, p. 149, p. 150

[32]Same as above, p. 151, p. 153

[33]Same as above, p. 149, p. 151

[34]Same as above, p. 151, p. 153

[35][Ancient Greek]: Aristotle: Physics, trans. Zhang Zhuming, Commercial Press, 1982, p. 74, 202b21

[36][French] Alexandre Koyré: Newtonian Studies, trans. Zhang Butian, Peking University Press, 2003, p. 76, pp. 72–73

[37][French] Alexandre Koyré: Newtonian Studies, trans. Zhang Butian, Peking University Press, 2003, p. 80, p. 78

[38] [American] Thomas Kuhn: The Essential Tension, trans. Fan Dainian, Ji Shuli et al., Peking University Press, 2004, p. 29, p. 30

Latest Comments

Gu Bo2008-12-12 21:39:50
The sharpest criticism of this article would be to say that the problem I raise is in fact a pseudo-problem caused entirely by translation of language.

For example, a senior student pointed out: “The ‘force’ in ‘dynamics’ is of course different from the ‘force’ in Aristotle’s so-called ‘efficient cause’; it is entirely a matter of translation. The former is dynamic, the latter is efficient. In fact, translating it as efficient cause is inaccurate; efficient cause may be more precise. I can say that efficient cause was simply mistranslated.”

Although my Western-language skills are very poor and I have not conducted any in-depth investigation, I did already have such elementary understandings long ago. In fact, is translating “dynamic” as “dynamics” really accurate? “Dynamic” seems to mainly mean movement and change, and has little to do with “force” at all! Why should it be translated as “dynamics” rather than something like “dynamic studies”? (There seem to be things like chemical dynamics and molecular dynamics.)

The key point is that whether it is “efficient cause” or “dynamics,” or “efficient cause” or “dynamic studies,” these concepts really do have “force” seeped into them—the concept understood through pushing and pressing. What I care about is this concept.

I do not need to concern myself with whether Aristotle’s “efficient cause” should properly be translated as efficient cause or dynamic cause or something of the sort; in any case, it is asking after a “pusher.” Or if you say that this “pushing” is itself mistranslated, and that “one who exerts efficacy,” “agent,” “doer,” and so on would all do, that is fine too. The point is that this is a role that actively exerts influence. That is enough.

My entire discussion does not need to be rigidly bound to the wording in Chinese. You are free to adjust the translation as you see fit, and my argument will not be undermined.

In a certain sense, my question is indeed not an easy one for Westerners to pose, because in modern Western languages the corresponding lexical items for vitality, thrust, gravity, force, efficacy, capacity, dynamism, dynamics, mechanics, magic, power… and so on are mostly different; whereas in Chinese, we can very easily see at a glance some common element among these concepts. The fact that Westerners use different words to describe these concepts does not mean that the common element among them does not exist in their world of thought! It is precisely this common element that led Chinese, when translating these concepts, to use the character “力” [li, force] consciously or unconsciously; and when we grasp the meanings of these concepts, we also do not feel that this character “力” is in any way out of place. This “力” is in fact embedded in, or permeates, these concepts. Some such “embeddedness” is original—for example, “vitality,” “thrust,” and “force”; while others were “inserted” only through the development of modern science, such as “mechanics.” And what I want to discuss is how this “力” of “thrust” came to be taken for granted as embedded within “mechanics.” You can change all these translations, for example calling “driving” A, “efficient cause” B, the force in Newtonian mechanics C, and the mechanical/mechanistic view of nature D. Fine, then my question is this: the concept B is understood together with A; C also contains the tradition of the concept A and is still understood today through the metaphor of A, and C becomes the core of D. But A is originally anthropomorphic, whereas D is precisely the opposite, so how could the concept C, carrying A along with it, possibly fuse with D? I point out that C is a substitution for A: Newton borrowed the conceptual tradition in which A and B were entangled and defined C, but in this definition he quietly flattened out the asymmetry within it, thereby making it in fact impossible for the concept B to remain, and making it possible for the concept C—which merely retained the traces of A and B while emptying out their substance—to fuse with D. Thanks to Newton’s and his successors’ outstanding work of mathematization, this fusion became extremely successful, so much so that the C-D concept in turn came to dominate people’s understanding of A-B, and then, under the new pattern of thought governed by C-D, people suddenly found that B could no longer be found at all. At the same time, by means of D, any anthropomorphism and mystery that might have remained in C from A-B were also eliminated. That’s all there is to it. Translate A, B, C, and D however you like; that is what I mean.

Among the various meanings of “力,” I suspect that “vitality” and “thrust” ought to be the most original ones (psychology and history both seem to support this), and the derivative meanings that follow would be “force” (the more original way of saying it ought to be “strength”), “effort,” “capacity,” “dynamism,” and so on. Meanings derived from these derivatives might then include “magic power” and “power” in the sense of political power. But however one extends these meanings, it seems impossible to derive “mechanics” from the concept’s own logic! That is the strange thing. So if the “力” in “mechanics,” which is synonymous with mechanics, is not the result of natural conceptual evolution, then some special event must certainly have occurred, causing this concept of “力” to deviate significantly from its original meaning, and thereby making it possible for this concept to be “inserted” into place. To my mind, that special event is the conceptual revolution marked by Newton’s third law.
Gū Mò2008-12-12 21:57:30
Actually, the layer of “vitality” within the concept of “力” has not yet been discussed in my article. The Latin concept of force (vis) seems to include both “vitality” and “thrust” at the same time, and Aristotle’s efficient cause in fact also contains these inner and outer layers. In Newton, too, both kinds of force are still there: external force is interpreted as interaction, while internal force is called “inertial force” by Newton. Of course, later developments in physics directly renamed “inertial force” as “inertia,” and turned “force” into a purely external “force.” The concept of internal “vitality” probably meandered through many turns and finally evolved into “energy.” That is another story altogether. But it also has a relationship to Newton’s revolution.
Gū Mò2008-12-12 23:05:29
Let me take this opportunity to sigh a little about Chinese~ Chinese is truly a marvelous language. If you look at it from the standpoint of analytic philosophy and positivism, Chinese is the language least suited to argument and inference; but if you look at it from the standpoint of phenomenology and hermeneutics, you will discover that Chinese is truly the language best suited to “questioning.” It is almost too easy to “discover problems”: just open a dictionary and look at those identical characters shared by utterly different words, such as “AB” and “CB.” If the B in B is not the same merely by coincidence or borrowing—for example, the 后 in “queen” and the 后 in “later” were originally two different things, and only happened to be merged by the simplification of Chinese characters—if that possibility is ruled out, that is to say, if we confirm that the B in “AB” and the B in “CB” are indeed the very same character, and if at the same time you discover that the word “AB” and the word “CB” seem to have nothing whatsoever to do with each other, then a problem arises: “How can the B in AB become the B in CB? What relation do AB and CB really have?” This question is almost certainly meaningful! In particular, the greater the apparent distance between the words “AB” and “CB,” the more room there is here to work! There may well be some hidden, long-forgotten, profound connection between these two words. And the incomparable advantage of Chinese is that even when the original meaning of a word has long been forgotten, such connections can still remain tenaciously within Chinese through the help of character form, sound, polyphonic characters, and polysemous characters, and can easily be spotted at a glance by those who pay attention. Similar things in Western languages have to be reconstructed through tracing the historical evolution of concepts, and the residual information in their forms and sounds is quite meager. Chinese can let you notice the problem first, and then carry out more targeted textual research afterward.

Take, for instance, the “后” in “queen” and the “後” in “later.” In fact, originally they were neither synonymous nor from the same source; they were basically unrelated, and according to the natural logic of conceptual evolution, they could never have come together. But due to a special external factor, namely the event of simplified Chinese characters, “後” was forcibly inserted into “后,” and the two were kneaded into a single character. Thus, if one is unaware of this event and mistakenly assumes that 后 and 後 have always been the same character, then it is highly possible to unconsciously alter one’s understanding of both characters at the same time! For example, when we speak of “皇后” [queen], children today may very likely think: it means “the one behind the emperor,” right! This guess also seems quite natural, and appears to be connected to the meaning of the word queen, but in fact it departs from the original meaning of the character “后” and is entirely a misunderstanding.

So if we look at the “力” in “efficient cause” and the “力” in the “mechanical/mechanistic view of nature,” are they the same character? If the relation between them is also not the result of the natural differentiation and transformation of concepts, but rather something artificially mixed together by some special event, then we need to understand that event. If we lack reflection on this, then it is entirely possible to arrive at many unconscious misunderstandings, and to ascribe without criticism, and as a matter of course, meanings that the concepts did not originally possess. For example, “力” is taken to carry the meaning of “non-anthropomorphization” (disenchantment), while “mechanism” is taken to have explanatory power; yet these meanings are by no means self-evident.
Gū Mò2008-12-13 18:49:04
Summary:

At the beginning of this article, the author raises the question: why is “mechanics” equivalent to “force,” or rather, how did the concept of “force” become the key term of the mechanistic view of nature? By tracing the intellectual history of the concept of “force,” this article attempts to reveal its origins and meanings.

First, the author proposes that the concept of “force” is originally associated with the impression of “driving” (and at the same time pulling and pushing). At the same time, “driving” is also the initial understanding of the concept of “cause.” Further, from Aristotle to the period of the Scientific Revolution, the concept of “force” was also always associated with the concept of cause in the narrow sense: to inquire into force is to ask after causes, and vice versa.

Subsequently, the author finds that in the sciences before Newton, the concept of “force” was not embedded within the mechanistic view of nature; rather, it was the opposite: the concept of “force” often represented precisely the part that stood opposed to “mechanism,” namely a certain anthropomorphic, mysterious, supernatural meaning, becoming the still-unmechanized fissure within the mechanical world. It was only after Newton that this fissure was filled in, and “force” changed from something supernatural, from something that explained irregularity, from something enchanted, into the basis of natural law, only then becoming embedded at the core of the mechanistic view of nature.

Finally, the author points out that the above conceptual revolution is marked by Newtonian mechanics, especially by its third law. It is precisely the third law that quietly displaced the content of “force,” replacing the anthropomorphic, directional, enchanted concept of “driving” with the neutral, nonhierarchical, disenchanted concept of “interaction.” Only then did the concept of “force” become able to merge with “mechanism.” Yet the price was that the new concept of “force” lost its connection with “cause”; “interaction” eliminated the distinction between “driver” and “driven,” eliminated the distinction between active and passive in the act of exerting force, between what comes before and what comes after, or in other words, between cause and result.

Because of the enormous mathematical success of Newtonian mechanics, the new concept of force took hold in people’s minds without serious reflection and became a new mental habit. In turn, many of the original connotations of “force” were driven out or forgotten by people, eventually causing mystery and anthropomorphism to be removed from the new worldview, while the efficient cause as the concept of cause in the narrow sense could no longer be found anywhere, and purpose and difference withdrew from the world along with it. The author does not judge whether this consequence is right or wrong, good or bad; however, what is beyond doubt is that this profoundly significant transformation is worth knowing and reflecting upon.

http://hps.phil.pku.edu.cn/bbs/read.php?tid=861&page=e#a

QUOTE:

Quoted in the 6th floor post by inobu at 2008-12-12 15:32:

Forgive my ignorance, but why don’t I see the answer to the question? Why are mechanics and mechanism expressed by a single word?… Well, I admit I didn’t read every single character… I also strongly suggest summarizing the line of thought and the conclusion.

____

Your question is reasonable. In fact, in my original conception, this article also had a final paragraph, “Force = nothing = everything—the conclusion,” where the point would be made once again. But by a little after midnight, I felt it was about enough, and I didn’t want to keep writing, so I took a knife and chopped the conclusion section right off.

The key point is that there was originally another design for the final paragraph: namely, to connect it to philosophy. I had planned to focus on two people, one of them being Hume—by the time we get to Hume, all of a sudden we discover that the thing called “causality” can no longer be found anywhere! This gives rise to many epistemological difficulties, and right through to twentieth-century philosophy of science, we see Salmon and others desperately trying to figure out how “scientific explanation” can explain causality, but no matter how they go about it, they still cannot get it straight—why? Why is it precisely in this era that problems of epistemology appear? I think that to understand this situation, we cannot avoid understanding the hidden revolution brought about by Newton’s third law—Hume must have appeared after Newton! The second is Schopenhauer. Schopenhauer was fully aware of the marvel of the concept of “force”; he pointed out that under the governance of the concept of force, the entire natural sciences appear to be orderly and systematic, everything seems perfectly clear and understandable, yet precisely the concept of force is the most uncanny and least understandable thing of all! Schopenhauer declared that “force” is nothing other than “will”; if we combine his philosophy with the changes in the concept of “force,” it takes on a rather different significance.

However, to write it that way would obviously still require a great deal of effort, and there wasn’t enough time, so when it got to a little after 12, I simply cut off the plan for the final paragraph with one stroke. But along with that, I also forgot the concluding point I had originally intended to place at the very end. That was my oversight.

The main problem is that I did not give a clear definition of “mechanism” (mechanistic theory, mechanistic philosophy, the mechanistic worldview). Actually, in simple terms, it’s very simple: “mechanism” is dehumanized, disenchanted, cold and ruthless. “Force” was originally an anthropomorphic thing, something understood through human touch, whereas mechanism is a nonhuman thing, something understood through sight and mathematical calculation. “Force” implies a relation between active and passive, whereas the various parts of “mechanism” are linked in motion without qualitative difference. Put simply, that is what it is. “The mechanization of force,” in simple terms, is the disenchantment of the world.

Of course, the title “The Mechanization of ‘Force’” is not a very good one; I simply couldn’t be bothered to think more. In fact, this title was a response to another assignment from two and a half years ago in Wu Laoshi’s class! Back then I wrote “The Expansion of ‘Matter’” (http://epr.ycool.com/post.1248147.html). At that time, in a footnote I mentioned: “The ‘dynamics’ in ‘dynamics’ is obviously different from the ‘dynamics’ in Aristotle’s so-called ‘efficient cause,’ but there is still something in common between them; there is no need to get hung up here on the literal meaning.” But in fact that was a bit of a sleight of hand, because at that time I had not given much thought to, or investigated, the historical evolution of the concept of “dynamics.” This paper today can also count as the completion of work that was already buried two and a half years ago! So when thinking up the title, I couldn’t help recalling that earlier article, and in the end it was fixed as this name.
Gū Mò2008-12-14 16:58:47
The conception of this title is also related to the course on selected readings in the original texts of philosophy of science that I took—when we look at Salmon’s various discussions of the DN model, the focus of the problem is all on this “causality” business; people find that models of scientific explanation are always difficult to satisfy the intuitive demand for causal explanation, either because they cannot provide causal explanation, or because the causal explanation they do provide is counterintuitive.

I was thinking that perhaps it is fundamentally impossible for “scientific explanation” to provide an intuitive causal explanation, because the causality most intuitively understood by people is always still “efficient cause,” whereas modern science is fundamentally a rejection of efficient cause. The relation of “force” is stripped of temporality and direction, and explanations in terms of the inner vitality, impulse, tendency, and so on of things—those enchanted explanations—have long since been excluded; scientific laws explain events by means of “force,” and “force” can only admit completely external and equal relations of action, so in principle it is impossible to provide an explanation in terms of efficient cause. Therefore, the effort to have scientific explanation provide an intuitive explanation of causes is probably doomed to be futile.