Principles of Newtonian Science

The powerful and highly influential principles of Newtonian science can be summarized as follows:

■ Although God is the creator of the world, he does not actively intervene in the events of the world (deism). It is therefore inappropriate to

invoke his will as an explanation of any particu- lar thing or event in the material world.

■ The material world is governed by natural laws, and there are no exceptions to these laws.

■ There is no place for purpose in natural law, and therefore Aristotle’s final causes must be rejected. In other words, natural events can never be explained by postulating properties inherent in them. Bodies fall, for example, not because of an inherent tendency to fall but because of various forces acting on them. That is, as a New- tonian scientist, one must not invoke teleological explanations.

■ Occam’s razor is to be accepted. Explanations must always be as simple as possible. In Book III of his Principles (1687/1995), Newton gives this advice: “We are to admit no more causes of nat- ural things than such as are both true and suffi- cient to explain their appearances”. This is the same principle that led Copernicus and many of his fellow mathematicians to reject the geocentric system in favor of the heliocentric system. Because with God, the simplest is always the best, so it should be the same with mathe- maticians and scientists. Newton’s conception of the universe could not have been simpler. Everything that happens can be explained in terms of (1) space, consisting of points; (2) time, consisting of moments; (3) matter, existing in space and possessing mass; and (4) force, provid- ing change in the motion of matter. Newton and his followers believed that the entire physi- cal universe could be explained in terms of these four constructs. In fact, an explanation of any natural event meant restating it mathematically in terms of space, time, matter, and force.

■ Natural laws are absolute, but at any given time our understanding is imperfect. Therefore, scientists often need to settle for probabilities rather than certainty. This is because of human ignorance, not because of any variance in natural laws.

■ Classification is not explanation. To note that chasing cats seems to be a characteristic of dogs more and more explanations were now being given “without benefit of clergy.”