External force
A visual of the human movement "driven" by external forces, and or possibly internal forces, in mechanism connectivity, according to 1796 human chemical theory of German polymath Johann Goethe, showing a human chemical reaction occurring via the action of the electromagnetic force; using the exchange force model of mediated or induced movement interactions.
In chnopsology, external force or “forces external in origin” refers to the discussion as to whether or not animate movement, such as chemicals, plants, or humans occurs or is a result, completely, in large part, or partially, of external forces or forces external to the bodies that are moved—or, conversely, if the movement is solely or even partially the result of an internal force.

Buckle
The gist of English historian Henry Buckle’s model of history, according to Morris Zucker, is that he relegates the individual to function as a register of the external material forces. [7]

Thermodynamics
The science of thermodynamics has a very clear position on the question of forces and movement. The definitive answer to the question is found in the opening paragraph of German physicist Rudolf Clausius' 1875 chapter “Mathematical Introduction: on Mechanical Work, on Energy, and on the Treatment of Non-Integrable Differential Equations”, which states the following:

“Every force tends to give motion to the body on which it acts; but it may be prevented from doing so by other opposing forces, so that equilibrium results, and the body remains at rest. In this case the force performs no work. But as soon as the body moves under the influence of the force, work is performed.”

This is the definitive underlying definition to all of thermodynamics—and in this sense, the movement of any body in the universe, such as a atom, molecule, chemical, animal, human, planet, etc., seem to be absolutely and definitively to be "under the influence of the force", as Clausius puts it, of two varieties: moving forces (or motive forces) and opposing forces.

Overview
Although the definitive Clausius definition of how bodies move, is very clear and straight forward the application of this model to the subject of how humans move is a bit involved, to say the least. To exemplify, English chemist-physicist Isaac Newton, the main founder of the model that things, i.e. particles or bodies (with mass) move only under the influence of forces, commented the following possible exemption of humans and animals from the laws of motion: [1]

God who gave animals self motion beyond our understanding is without a doubt able to implant other principles of motion in bodies which we may understand as little. Some would readily grant this may be a spiritual one; yet a mechanical one might be shown.”

This “animals have self motion” model, a power given to them by the hand of God, to give some historical review, is the creation by breath model passed along through the ages, in the format of the Anunian theologies: Christianity, Islam, and Hinduism, to Newton and the culture of his time and, of course, is an example of perpetual motion of the living kind, and as is the case with all perpetual motion theories, is something that is untenable. Two other alternative or differing points of view on this matter are shown below.

Spontaneity | Largely governed by external forces
In 1796, German polymath Johann Goethe, in his Third Lecture on Anatomy (see: Goethe timeline), stated the following logic in regards to his view that the forces that move humans and chemicals one way or another are often purely external in origin: [2]

“There are, by nature, stronger or weaker bonds between chemical components, and when they evidence themselves, they resemble attractions between humans. This is why chemists speak of elective affinities [A = -ΔG], even though the forces that move chemicals [or humans] one way or another and create chemical structures are often purely external in origin.”

This is what Goethe defines as the concept of “organic existence”, and in modern post 1923 terms is representative of the “driving force” model of chemical processes, in which the quantitative measure of the driving force is free energy, Gibbs free energy for human movements and interactions.

A similar point of view can be found in American physician George Carey's 1919 Chemistry of Human Life, wherein he states: [5]

“The human organism is an intelligent entity that works under the guidance which man has designated as chemical affinity.”

Carey, to note, utilized a bit of a blurry religious tinge to his chemistry writings, but, nevertheless, this one statement, whether or not by "guidance" he means "hand of God", or something along these lines, is cogent, religious issues aside.

Spontaneity | Not governed by external forces
English-born American philosopher Alan Watts, in his circa 1971 lecture “Works and Play” (14:30-15:00), shown adjacent, explains his views on nature in relation to external forces as follows: [3]

“Living, you see, like this plant, is something spontaneous. In Chinese, the word for nature is dàzìrán (大自然), which means that which happens with itself, not under any control of an outside force, and they feel that all of the world is happening in and of itself—it’s spontaneous.”

Watts model, here, is a bit of a poetic or rather he presents a hued distortion of reality; whereas, correctly, the first cogent cold hard physical science explanation of "spontaneity" was outlined by German physical chemist Walther Nernst in 1893 in terms of free energy minimization. [4]

A more recent example is that given by American philosopher Christian de Quincey who in his 2002 book Radical Nature, uses the extrapolate downward approach to argue, in short, that since people are perceived to be self-moving that so to must fermions and bosons be sentient and and self-moving: [6]

“If the universe is not ‘dead’, if it is not simply a huge mechanical system running according to a handful of laws at work in a vast ocean of chaos then it is in some sense ‘alive’. A more accurate term would be ‘sentient’—an inherent capacity for feeling or experience. In other words, to make explicit the main argument of the book: the matter of the universe, its raw stuff or ingredients, has within itself the essence of what we call ‘consciousness.’ There is something about matter itself, some quality or property, some intrinsic principle, that moves matter from within, an automotive urge toward self-organization, evolution, and complexity. In short, matter feels and moves itself. It doesn’t require external forces pushing and pulling it.”

To summarize, correctly, according to the defunct theory of life, in unison with Nernst's definition of things, a plant is not alive, as Watts' supposes, but rather is a periodic table structure type of a surface-attached cyclically-heated chemical process or animate growth reaction, and as is the case with all processes and reactions, will only advance in the "sense of a diminution of free energy, i.e. only in the sense of the affinity". In short, the free energy is the overarching "universal rule" that overrides or rather is the summation deciding factor in whether or not the process of the system as a whole will ensue.

See also
Driving force
Exchange force
Social force
Thermodynamic force
Motive force
Living force
Fall-force
Entropic force
Force function
Self drive | see: "self drive" (threads)

References
1. Gleick, James. (2003). Isaac Newton (self motion, pg. 105). Vintage.
2. (a) Goethe, Johann. (1796). Lectures on Anatomy, I, 9, pg. 202f.
(b) Eigen, Manfred, and Winkler, Ruthild. (1993). Laws of the Game: How the Principles of Nature Govern Chance (pg. 74-77). Princeton University Press.
3. (a) Watts, Alan. (c.1971). “Work as Play”, Video publisher.
(b) Chinese word for nature – BrightHub.com.
4. (a) Nernst, Walther. (1893). Theoretical Chemistry from the standpoint of Avogadro's rule and Thermodynamics (Theoretische Chemie vom Standpunkte der Avogadroschen Regel und der Thermodynamik). Stuttgart, F. Enke, 1893 [5th edition, 1923].
(b) Nernst, Walther. (1895). Theoretical Chemistry: from the Standpoint of Avogadro’s Rule & Thermodynamics (697-pages) (section: The Measure of Affinity, pgs. 586-88). MacMillan and Co.
(c) Nernst, Walther. (1904). Theoretical Chemistry: from the Standpoint of Avogadro’s Rule & Thermodynamics (771-pages). MacMillan and Co.
5. Carey, George W. (1919). The Chemistry of Human Life. Los Angeles: The Chemistry of Life Co.
6. De Quincey, Christian. (2002). Radical Nature: Rediscovering the Soul of Matter (quote, pg. 41). Invisible Cities Press.
7. Zucker, Morris. (1945). The Philosophy of American History: The Historical Field Theory (pgs. 55-56). Arnold-Howard Publishing Co.

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