Aristotle believed that force causes motion, but his thoughts on motion were vague.[i]  Galileo believed more accurately that motion is normal; that force causes a change in motion.


Newton followed up on Galileo’s observation. In his Philosophiae Naturalis Principia Mathematica, or Principia, first published in 1687, Newton extrapolated on the work of Brahe and Kepler to develop his universal laws of motion and the  law of gravitation.[ii] It has been said that Newton unified heaven and earth with his theory of gravity.


The conceptual giant of “Newtonian Mechanics” developed over the next decades after the Principia, and required the contribution of many more scientists. The Newtonian universe is made up of matter in empty space. Although Newtonian Mechanics applies only to the motions of macroscopic bodies, it was thought by its supporters that if one had the necessary data, the actions of the universe could be predicted, like clockwork, at any given time in the future. The clockwork universe lends itself to the concept of absolute time and space.


Interestingly, Newton himself was not an absolutist. He believed that both absolute time and location are quantities which cannot be observed, but must be inferred from relative time and location.


Even with the assumption of absolute time and space , the Newtonian clockwork universe was doomed to failure. The French Mathematician Henri Poincare dealt perhaps the first blow to the idea when he found that Newton’s laws only suffice for two point masses. For formal mathematical reasons, Newton’s basic equations become unsolvable for even only three bodies; the answer can only be found by a series of approximations. Poincare’s discovery was an early step in the development of Complexity or Chaos theory[iii]. The Newtonian grand machine concept of the universe was not valid in even the most rudimentary sense.


Nevertheless, Newtonian Mechanics dominated western science for centuries

[i] Aristotle said "motion is the fulfillment of what exists  potentially insofar as it exists potentially"

Change and motion: Calculus made clear  The Teaching Company

[ii] The First law or law of inertia: Every body perseveres in its state of being at rest or of moving uniformly straight forward except insofar as it is compelled to change its state by forces impressed. The Second Law: A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed.

The  Third law; For every action, there is a reaction

Note that the Force = Mass times Acceleration formulation did not occur in any of the three editions of the Principia.


[iii] Turbulent Mirror. John Briggs and F.David Peat Harper Row, 1989 p.27


James Gleick has written that Chaos is the science of detecting order in apparent randomness. Chaos