"It is exemplified principally in some of the greatest discoveries. Thus it was found by Newton that the doctrine of the attraction of the sun varying according to the inverse square of the distance, which explained Kepler's _Third Law_ of the proportionality of the cubes of the distances to the squares of the periodic times of the planets, explained also his _First_ and _Second Laws_ of the elliptical motion of each planet; although no connexion of these laws had been visible before. Again, it appeared that the force of universal gravitation, which had been inferred from the _perturbations_ of the moon and planets by the sun and by each other, also accounted for the fact, apparently altogether dissimilar and remote, of the _precession of the equinoxes_. Here was a most striking and surprising coincidence, which gave to the theory a stamp of truth beyond the power of ingenuity to counterfeit.... ... The theory of universal gravitation, and of the undulatory theory of light, are indeed full of examples of this consilience of inductions. With regard to the latter, it has been justly asserted by Herschel, that the history of the undulatory theory was a succession of _felicities_. And it is precisely the unexpected coincidences of results drawn from distant parts of the subject which are properly thus described." ("Philosophy of the Inductive Sciences," B. XI., chap. v., s. 3.) And again, "It is true, the explanation of one set of facts may be of the same nature as the explanation of the other class; but then, that the cause explains _both_ classes, gives it a very different claim upon our attention and assent from that which it would have if it explained one class only. The very circumstance that the two explanations coincide, is a most weighty presumption in their favour. It is the testimony of two witnesses in behalf of the hypothesis; and in proportion as these two witnesses are separate and independent, the conviction produced by their agreement is more and more complete. When the explanation of two kinds of phenomena, distinct, and not apparently connected, leads us to the same cause, such a coincidence does give a reality to the cause, which it has not while it merely accounts for those appearances which suggested the supposition. This coincidence of propositions inferred from separate classes of facts, is exactly what we noticed in the last book, as one of the most decisive characteristics of a true theory, under the name of _Consilience of Inductions_.