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Bacon was the first of the long line of scientifically minded philosophers who have emphasized the importance of induction as opposed to deduction. Like most of his successors, he tried to find some better kind of induction than what is called “induction by simple enumeration.” Induction by simple enumeration may be illustrated by a parable. There was once upon a time a census officer who had to record the names of all householders in a certain Welsh village. The first that he questioned was called William Williams; so were the second, third, fourth, . . . At last he said to himself: “This is tedious; evidently they are all called William Williams. I shall put them down so and take a holiday.” But he was wrong; there was just one whose name was John Jones. This shows that we may go astray if we trust too implicitly in induction by simple enumeration.
Bacon believed that he had a method by which induction could be made something better than this. He wished, for example, to discover the nature of heat, which he supposed (rightly) to consist of rapid irregular motions of the small parts of bodies. His method was to make lists of hot bodies, lists of cold bodies, and lists of bodies of varying degrees of heat. He hoped that these lists would show some characteristic always present in hot bodies and absent in cold bodies, and present in varying degrees in bodies of different degress of heat. By this method he expected to arrive at general laws, having, in the first instance, the lowest degree of generality. From a number of such laws he hoped to reach laws of the second degree of generality, and so on. A suggested law should be tested by being applied in new circumstances; if it worked in these circumstances it was to that extent confirmed. Some instances are specially valuable because they enable us to decide between two theories, each possible so far as previous observations are concerned; such instances are called “prerogative” instances.
Bacon not only despised the syllogism, but undervalued mathematics, presumably as insufficiently experimental. He was virulently hostile to Aristotle, but thought very highly of Democritus. Although he did not deny that the course of nature exemplifies a Divine purpose, he objected to any admixture of teleological explanation in the actual investigation of phenomena; everything, he held, should be explained as following necessarily from efficient causes.
He valued his method as showing how to arrange the observational
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data upon which science must be based. We ought, he says, to be neither like spiders, which spin things out of their own insides, nor like ants, which merely collect, but like bees, which both collect and arrange. This is somewhat unfair to the ants, but it illustrates Bacon’s meaning.
One of the most famous parts of Bacon’s philosophy is his enumeration of what he calls “idols,” by which he means bad habits of mind that cause people to fall into error. Of these he enumerates five kinds. “Idols of the tribe” are those that are inherent in human nature; he mentions in particular the habit of expecting more order in natural phenomena than is actually to be found. “Idols of the cave” are personal prejudices, characteristic of the particular investigator. “Idols of the market-place” are those that have to do with the tyranny of words and the difficulty of escaping from their influence over our minds. “Idols of the theatre” are those that have to do with received systems of thought; of these, naturally Aristotle and the scholastics afforded him the most noteworthy instances. Lastly there are “idols of the schools,” which consist in thinking that some blind rule (such as the syllogism) can take the place of judgement in investigation.
Although science was what interested Bacon, and although his general outlook was scientific, he missed most of what was being done in science in his day. He rejected the Copernican theory, which was excusable so far as Copernicus himself was concerned, since he did not advance any very solid arguments. But Bacon ought to have been convinced by Kepler, whose New Astronomy appeared in 1609. Bacon appears not to have known of the work of Vesalius, the pioneer of modern anatomy, or of Gilbert, whose work on magnetism brilliantly illustrated inductive method. Still more surprising, he seemed unconscious of the work of Harvey, although Harvey was his medical attendant. It is true that Harvey did not publish his discovery of the circulation of the blood until after Bacon’s death, but one would have supposed that Bacon would have been aware of his researches. Harvey had no very high opinion of him, saying “he writes philosophy like a Lord Chancellor.” No doubt Bacon could have done better if he had been less concerned with worldly success.
Bacon’s inductive method is faulty through insufficient emphasis on hypothesis. He hoped that mere orderly arrangement of data would make the right hypothesis obvious, but this is seldom the case. As a
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rule, the framing of hypotheses is the most difficult part of scientific work, and the part where great ability is indispensable. So far, no method has been found which would make it possible to invent hypotheses by rule. Usually some hypothesis is a necessary preliminary to the collection of facts, since the selection of facts demands some way of determining relevance. Without something of this kind, the mere multiplicity of facts is baffling.
The part played by deduction in science is greater than Bacon supposed. Often, when a hypothesis has to be tested, there is a long deductive journey from the hypothesis to some consequence that can be tested by observation. Usually the deduction is mathematical, and in this respect Bacon underestimated the importance of mathematics in scientific investigation.
The problem of induction by simple enumeration remains unsolved to this day. Bacon was quite right in rejecting simple enumeration where the details of scientific investigation are concerned, for in dealing with details we may assume general laws on the basis of which, so long as they are taken as valid, more or less cogent methods can be built up. John Stuart Mill framed four canons of inductive method, which can be usefully employed so long as the law of causality is assumed; but this law itself, he had to confess, is to be accepted solely on the basis of induction by simple enumeration. The thing that is achieved by the theoretical organization of science is the collection of all subordinate inductions into a few that are very comprehensive –perhaps only one. Such comprehensive inductions are confirmed by so many instances that it is thought legitimate to accept, as regards them, an induction by simple enumeration. This situation is profoundly unsatisfactory, but neither Bacon nor any of his successors have found a way out of it.
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CHAPTER VIII Hobbes’s Leviathan
HOBBES ( 1588-1679) is a philosopher whom it is difficult to classify. He was an empiricist, like Locke, Berkeley, and Hume, but unlike them, he was an admirer of mathematical method, not only in pure mathematics, but in its applications. His general outlook was inspired by Galileo rather than Bacon. From Descartes to Kant, Continental philosophy derived much of its conception of the nature of human knowledge from mathematics, but it regarded mathematics as known independently of experience. It was thus led, like Platonism, to minimize the part played by perception, and over-emphasize the part played by pure thought. English empiricism, on the other hand, was little influenced by mathematics, and tended to have a wrong conception of scientific method. Hobbes had neither of these defects. It is not until our own day that we find any other philosophers who were empiricists and yet laid due stress on mathematics. In this respect, Hobbes’s merit is great. He has, however, grave defects, which make it impossible to place him quite in the first rank. He is impatient of subtleties, and too much inclined to cut the Gordian knot. His solutions of problems are logical, but are attained by omitting awkward facts. He is vigorous, but crude; he wields the battle-axe better than the rapier. Nevertheless, his theory of the State deserves to be carefully considered, the more so as it is more modern than any previous theory, even that of Machiavelli.
Hobbes’s father was a vicar, who was ill-tempered and uneducated; he lost his job by quarrelling with a neighbouring vicar at the church door. After this, Hobbes was brought up by an uncle. He acquired a good knowledge of the classics, and translated The Medea of Euripides into Latin iambics at the age of fourteen. (In later life, he boasted, justifiably, that though he abstained from quoting classical poets and orators, this was not from lack of familiarity with their works.) At
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fifteen, he went to Oxford, where they taught him scholastic logic and the philosophy of Aristotle. These were his bugbears in later life, and he maintained that he had profited little by his years at the university; indeed universities in general are constantly criticized in his writings. In the year 1610, when he was twenty-two years old, he became tutor to Lord Hardwick (afterwards second Earl of Devonshire), with whom he made the grand tour. It was at this time that he began to know the work of Galileo and
