Quote by Isaac Newton

“considerable intellectual achievement. In particular, we should take note that this attitude enabled Newton to explore the conjectured consequences of philosophic questions as a form of “dreaming,” without thereby necessarily undermining in any way the results of the Principia, without thereby producing a “philosophical romance” in the way that Descartes was said to have done. I repeat what Newton said in the last paragraph of that preface: “And although the whole of philosophy is not immediately evident, still it is better to add something to our knowledge day by day than to fill up men’s minds in advance with the preconceptions of hypotheses.” Certain fundamental truths, such as the universality of the force of gravity acting according to the inverse-square law, were derived directly from mathematics; but in Newton’s mind even such a law—once found—had to be fitted into his general scheme of thought, and he came to believe that certain aspects of this law had been known to the ancient sages. Following the reorientation of Newton’s philosophy of nature, he came to believe that interparticle forces of attraction and repulsion exist. Such forces, according to Newton, are sufficiently short-range in their action (as he makes quite explicit in query 31 of the Opticks) that they do not raise a major problem of understanding their mode of action. They do not, in other words, fall into the category of the forces acting at a distance. His studies of matter, and in particular of alchemy, had made the existence of these forces seem reasonable. But does the reasonableness of such short-range forces provide a warrant for belief in the existence of long-range forces acting over huge distances? Consider the gravitational force between the sun and the earth: this force must act through a distance of about one hundred million miles. Even worse from the conceptual point of view is the force between the sun and Saturn, some thousands of millions of miles. Eventually Newton was to conclude that comets are a sort of planet, with the result that the solar gravitational force must extend”