Results.—The thinkers whose speculations have engaged us were indeed responsible for creating a revolution in ideas. For a finite universe whose centre was the earth, and which was kept in motion by the operation of the Deity, they had substituted the conception of illimitable space sown with innumerable systems like our own; and had created the beginning of a mechanical conception of nature.
The New Logic.—But it was not only the scientific dogmas of the old system that had been so rudely overthrown—the very principles upon which those dogmas rested had been submitted to a destructive criticism. The new science produced a new logic. This order of events is not unusual: first, the new scientific discoveries, and then in the wake of the discoverers, comes the innovating critic who systematises the logical or scientific methods to which the new knowledge seems to have been due. First, Kepler and Galileo, who used the "inductive" method, and then Lord Bacon of Verulam (1561-1626), who discovered the inductive logic, and established it as a system.
Francis Bacon.—Bacon's doctrine may be summarised by his own epigram, "If a man begin with certainties, he shall end in doubts; but if he be content to begin with doubts, he shall end in certainties." Which is really a criticism of what is known as the a priori method, whereby the inquirer starts with certain predefined theories to which all phenomena must conform, and which all experience must verify. If facts will not suit the particular theory, so much the worse for the facts: one could always disregard them, and apply a blind eye to Galileo's telescope. Such is always the procedure of the dogmatic mind, which is already so certain of the truth of its notions that no evidence can persuade it to the contrary. But it is not by such means that knowledge is advanced, and it was for a reversal of these that Bacon pleaded.
Leonardo da Vinci had already anticipated the Baconian logic (which did not wait for Bacon until it was applied) when he laid down the proposition that wisdom was the daughter of experience, and rejected all speculations which experience, the common mother of all sciences, could not confirm. Hence, knowledge was the product of time; the process of collecting material for a judgment must often be slow, but the results were worth the labour—these would not be speculative, but true. Nor need it be supposed that Bacon excluded imagination from playing a part in increasing knowledge, he did not plead only for a mechanical collection of material. It is imagination which in face of abundant material creates the hypothesis which accounts for it being what it is. And he was prepared to admit the value of preliminary hypotheses which might be replaced as further facts were collected, or as insight became more clear. Here, too, Bacon describes the method followed by modern science.
Prestige of New Methods.—And so, by the time when Bacon had laid down his pen after writing the New Logic, the work of discrediting the old system, elaborated with such ingenious industry by Aquinas, was tolerably complete. The new science had begun already to be fruitful in results, both practical and speculative. The successors of Galileo and of Bacon applied the new principles with vigour, and reached astonishing results. Justified by these, the new methods secured a prestige which has not decreased for three centuries.
GROWTH OF THE MECHANICAL THEORY
Decline of Scholasticism.—By the time of Lord Bacon, the Scholastic philosophy might have been described as extinct; it no longer survived as a living system. The loss was a serious one to mankind, which was poorer by the discrediting of an authoritative body of thought, a possession it seems ill able to dispense with. The Baconian philosophy was an imperfect substitute; it was little more than a system of enquiry, a manual of scientific procedure, for Bacon himself was not in the philosophical sense a profound or constructive thinker, though he was one of those men of talent who can give utterance to the tendencies of an epoch.