Posted by: davidlarkin | January 26, 2010

What is a Force?


Sir Isaac Newton (1642-1727)

If you ask a physicist what a “force” is, he or she is likely to answer with a formula for measuring the effect of a force, like F=MA (Force = Mass X Acceleration) or “W=FD” (Work = Force X Distance, which translates to Force equals Work divided by Distance F=W/D).  However, the physicist has not told us what a “force” is, only how to measure it in terms of other variables, like “mass” and its “acceleration.” A force may equal mass times acceleration, but is a “Force” in its essence, a “mass” times its “Acceleration”?

A “Newton”, named after Isaac Newton, is the classic unit of measurement of force. In the F=MA formula, force of one Newton will be the product of a mass of one kilogram multiplied by an acceleration or rate of change in velocity in the amount of one meter per one second, N=KgM/S, but this is only a quantity stated in kilogram-meters per second. That does not tell us what a force is, only how big or small it is, relative to another quantity of force.

The dictionary definition of “force” is typically something as simple as “a pushing or a pulling” or as ambiguous as “a power to influence, to cause. . .”  A “power” is a “capacity” or “ability” or “capability” which is only a word substituting for the description of the quality of an object or thing that can cause an event. Thus, “Force” is a concept used in place of whatever it is that effectively causes a push or a pull, and may be called a “power,” if it inheres in a thing.  Gravity is a force because it is an attraction between things with mass, sometimes referred to by physicists as “bodies.”  If you think about it, you can see that no one really knows what a “force” is, what its essence is, but we can see a body, or a mass of matter (unless it is too small to see or as invisible as Dark Matter).

The great polymath genius, Gottfried Leibniz, who, contemporaneously with Isaac Newton, invented the calculus, concluded that gravity was miraculous:

If God would cause a body to move free in the aether round about a certain fixed centre, without any other creature acting upon it:  I say, it could not be done without a miracle;  since it cannot be explained by the nature of bodies.  For, a free body does naturally recede from a curve in the tangent.  And therefore I maintain, that the attraction of bodies, properly so called, is a miraculous thing, since it cannot be explained by the nature of bodies.

Alexander, H.G., editor The Leibniz-Clarke Correspondence, Manchester University Press (1956), p. 30.

Isaac Newton did not know what gravity was either, but he was adamant that it was not inherent in matter. He wrote:

It is inconceivable that inanimate brute matter should, without the mediation of something else which is not material, operate upon and affect other matter without mutual contact…That gravity should be innate, inherent, and essential to matter, so that one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it.

Janiak, A. (ed.), 2004, Newton: Philosophical Writings, Cambridge: Cambridge University Press, p. 104, cited in the Stanford Encyclopedia of Philosophy.

Force may be mechanical, when one billiard ball strikes another, or it may be a field, as in the case of gravity or electro-magnetism, but its essence remains undefinable. Physicists today are even using a gravity particle in their models, the graviton, to stand in the place of the force of attraction between bodies, as if bodies send invisible massless particles to cling to another body within a certain range and then the respective clouds of gravitons simultaneously push or pull the body towards their respective home bodies, with a strength proportional to the mass of the graviton’s home body, and the stronger cloud of gravitons prevails.

Do we need to know what a force is? If we do not know what it is, where it comes from, why it is here, then we do not know the ultimate source of what there is and what makes it change. We can ignore the essence of the forces in creation, respect it, fear it, or worship it.

The worlds of the Starwars films were managed by “The Force,” an impersonal mystical governing force, which was a conceptual substitute for the personal God who has filled the same role in the Judeo-Christian tradition, only with the historically revealed purposes of a conscious intelligent person.

For the Christian, Jesus Christ, the Word of God, and the person of the triune God by whom creation is carried out to completion, that divine person and his Holy Spirit is the force that holds the quarks in place and manifests further as the power that is harnessed within the nucleus of the atom, holding its parts together with the strong and weak nuclear forces, until released by massive man-made fission or fusion reactions; is the force referred to as gravity that holds a star together, while though natural fusion within the star, the energy of the forces holding the atoms together is released by means of natural fusion; and is the power that attracts dark matter towards the center of mass of a passing galaxy — and is the force that sends an apple to the earth:

He is before all things, and in him all things hold together.

Colossians 1:17 (ESV)

See my June 2, 2012 post “The Holy Spirit and Divine Action in the Material World at this link:


  1. Right on!

  2. […] What is a Force? […]

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