In human physics, social force is a force that results or is mediated by social interactions, processes, or reactions between human molecules, the underlying nature of which is the electromagnetic force. 
In 1728, John Desaguliers, in his The Newtonian System of the World: the Best Model of Government, outlined what seems to have been the first draft of a “Newtonian government”, arguing how the ideal government should be run according to celestial mechanics; the following is a related quote:
“A gravity-like force of attraction is now as universal in the political as in the philosophical world.”
— John Desaguliers (1728), The Newtonian System of the World 
In 1854, French philosopher Auguste Comte, in his System of Positive Polity: or System of Sociology, was theorizing about “social force”, in terms of things such “moral power”; the following being one truncated statement: (Ѻ)
“All social force is at once material, intellectual, and moral.”
In 1862, English natural philosopher Herbert Spencer was promoting some type of calculus of forces theory of social force.
In 1904, William James, in objection to Spencer's theory of social forces, raised the following objections: 
“But what on earth is ‘social force’? Sometimes he identifies it with ‘social activity’ (showing the latter to be proportionate to the amount of food eaten), and sometimes with the work done by human beings and their steam-engines, and shows it to be due ultimately to the sun’s heat. It would never occur to a reader of this pages that a social force proper might be anything that acted as a stimulus of social change,—a leader, for example, a discovery, a book, a new idea, or a national insult; and that the greatest of ‘forces’ of this kind need embody no more ‘physical force’ than the smallest. The measure of greatness here is the effect produced on the environment, not a quantity antecedently absorbed from physical nature. Mr. Spencer himself is a great social force; but he ate no more than the average man, and his body, if cremated, would disengage no more energy.”
The tricky issue that James is grappling with here, in regards to the discorrelation between the average food intake versus the average greatness of a person is that food intake is surface-substrate interaction factor that only effects the lowering of the activation energy barrier to a reaction, whereas free energy change is what quantifies the relative greatness of a person, in that the latter is a result of person-to-person or person-to-society human chemical reaction factors.
In 1922, Howard W. Odum established the Journal of Social Forces, renamed Social Forces (1925), a publication outlet focused on: sociology, primarily, but also related fields, such as: social psychology, anthropology, political science, history, and economics. 
In thermodynamic terms, the social force is quantified as Gibbs free energy differentials, aka the isothermal-isobaric "force function" or the driving force of human interactions, human reactions, and human processes. The translation of "free energy" to "force", to note, is not a one-to-one translation, being that according to the affinity-free energy equation, the affinity A or chemical affinity is the force of reaction, whereas the free energy change, F or G, or available energy measure of the affinities.
● Social pressure
● Entropic force
1. (a) Thims, Libb. (2007). Human Chemistry (Volume One). Morrisville, NC: LuLu.
(b) Thims, Libb. (2007). Human Chemistry (Volume Two). Morrisville, NC: LuLu.
2. Russett, Cynthia E. (1991). Sexual Science (pgs. 162-63; also: entropy, pg. 128). Harvard University Press.
3. Social Forces – Wikipedia.
4. (a) Desaguliers, John T. (1728). The Newtonian System of the World: the Best Model of Government - an Allegorical Poem (§:dedication). A. Campbell.
(b) Ball, Philip. (2016). “Describing People as Particles Isn’t Always a Bad Idea: Using Physics to Describe Social Phenomena Can Work – If It’s the Right Physics” (Ѻ), Nautilus, Feb 11.
● Social force model – Cs.UCF.edu.