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The inductive method has been practised ever since the beginning of the world by every human being. It is constantly practised by the most ignorant clown, by the most thoughtless schoolboy, by the very child at the breast. That method leads the clown to the conclusion that if he sows barley he shall not reap wheat. By that method the schoolboy learns that a cloudy day is the best for catching trout. The very infant, we imagine, is led by induction to expect milk from his mother or nurse, and none from his father.
Not only is it not true that Bacon invented the inductive method; but it is not true that he was the first person who correctly analysed that method and explained its uses. Aristotle had long before pointed out the absurdity of supposing that syllogistic reasoning could ever conduct men to the discovery of any new principle, had shown that such discoveries must be made by induction, and by induction alone, and had given the history of the inductive process, concisely indeed, but with great perspicuity and precision.
Again, we are not inclined to ascribe much practical value to that analysis of the inductive method which Bacon has given in the second book of the Novum Organum. It is indeed an elaborate and correct analysis. But it is an analysis of that which we are all doing from morning to night, and which we continue to do even in our dreams. A plain man finds his stomach out of order. He never heard Lord Bacon's name. But he proceeds in the strictest conformity with the rules laid down in the second book of the Novum Organum, and satisfies himself that minced pies have done the mischief. “I ate minced pies on Monday and Wednesday, and I was kept awake by indigestion all night.” This is the comparentia ad intellectum instantiarum convenientium. “I did not eat any on Tuesday and Friday, and I was quite well.” This is the comparentia instantiarum in proximo quæ natura data privantur. “I ate very sparingly of them on Sunday, and was very slightly indisposed in the evening. But on Christmas-day I almost dined on them, and was so ill that I was in great danger. This is the comparentia instantiarum secundum magis et minus. “ It cannot have been the brandy which I took with them. For I have drunk brandy daily for years without being the worse for it.” This is the rejectio naturarum. Our invalid then proceeds to what is termed by Bacon the Vindemiatio, and pronounces that minced pies do not agree with him.
We repeat that we dispute neither the ingenuity nor the accuracy of the theory contained in the second book of the Novum Organum ; but we think that Bacon greatly overrated its utility. We conceive that the inductive process, like many other processes, is not likely to be better performed merely because men know how they perform it. William Tell would not have been one whit more likely to cleave the apple if he had known that his arrow would describe a parabola under the influence of the attraction of the earth. Captain Barclay would not have been more likely to walk a thousand miles in a thousand hours, if he had known the place and name of every muscle in his legs. Monsieur Jourdain probably did not pronounce D and F more correctly after he had been apprised that D is pronounced by touching the teeth with the end of the tongue, and F by putting the upper teeth on the lower lip. We cannot perceive that the study of Grammar makes the smallest difference in the speech of people who have always lived in good society. Not one Londoner in ten thousand can lay down the rules for the proper use of will and shall. Yet not one Londoner in a million ever misplaces his will and shall. Doctor Robertson could, undoubtedly, have written a luminous dissertation on the use of those words. Yet, even in his latest work, he sometimes misplaced them ludicrously. No man uses figures of speech with more propriety because he knows that one figure is called a metonymy and another a synecdoche. A drayman in a passion calls out, “You are a pretty fellow,” without suspecting that he is uttering irony, and that irony is one of the four primary tropes. The old systems of rhetoric were never regarded by the most experienced and discerning judges as of any use for the purpose of forming an orator. “Ego hanc vim intelligo," said Cicero, “esse in præceptis omnibus, non ut ea secuti oratores eloquentiæ laudem sint adepti, sed quæ sua sponte homines eloquentes facerent, ea quosdam observasse, atque id egisse ; sic esse non eloquentiam ex artificio, sed artificium ex eloquentia natum.” We must own that we entertain the same opinion concerning the study of Logic which Cicero entertained concerning the study of Rhetoric. A man of sense syllogizes in celarent and cesare all day long without suspecting it; and though he may not know what an ignoratio elenchi is, has no difficulty in exposing it whenever he falls in with it; which is likely to be as often as he falls in with a Reverend Master of Arts nourished on mode and figure in the cloisters of Oxford. Considered merely as an intellectual feat, the Organum of Aristotle can scarcely be admired too highly. But the more we compare individual with individual, school with school, nation with nation, generation with generation, the more do we lean to the opinion that the knowledge of the theory of logic has no tendency whatever to make men good reasoners.
What Aristotle did for the syllogistic process Bacon has, in the second book of the Novum Organum, done for the inductive process; that is to say, he has analysed it well. His rules are quite proper; but we do not need them, because they are drawn from our own constant practice.
But, though every body is constantly performing the process described in the second book of the Novum Organum, some men perform it well, and some perform it ill.
Some are led by it to truth, and some to error. It led Franklin to discover the nature of lightning. It led thousands, who had less brains than Franklin, to believe in animal magnetism. But this was not because Franklin went through the process described by Bacon, and the dupes of Mesmer through a different process. The comparentiæ and rejectiones of which we have given examples will be found in the most unsound inductions. We have heard that an eminent judge of the last generation was in the habit of jocosely propounding after dinner a theory, that the cause of the prevalence of Jacobinism was the practice of bearing three names. He quoted on the one side Charles James Fox, Richard Brinsley Sheridan, John Horne Tooke, John Philpot Curran, Samuel Taylor Coleridge, Theobald Wolfe Tone. These were instantiæ convenientes. He then proceeded to cite instances absentiæ in proximo, William Pitt, John Scott, William Windham, Samuel Horsley, Henry Dundas, Edmund Burke. He might have gone on to instances secundum magis et minus. The practice of giving children three names has been for some time a growing practice, and Jacobinism has also been growing. The practice of giving children three names is more common in America than in England. In England we still have a King and a House of Lords : but the Americans are republicans. The rejectiones are obvious. Burke and Theobald Wolfe Tone are both Irishmen; therefore the being an Irishman is not the cause of Jacobinism. Horsley and Horne Tooke are both clergymen; therefore the being a clergyman is not the cause of Jacobinism. Fox and Windham were both educated at Oxford ; therefore the being educated at Oxford is not the cause of Jacobinism. Pitt and Horne Tooke were both educated at Cambridge;
therefore the being educated at Cambridge is not the cause of Jacobinism. In this way, our inductive philosopher arrives at what Bacon calls the Vintage, and pronounces that the having three names is the cause of Jacobinism.
Here is an induction corresponding with Bacon's analysis, and ending in a monstrous absurdity. In what then does this induction differ from the induction which leads us to the conclusion that the presence of the sun is the cause of our having more light by day than by night? The difference evidently is not in the kind of instances, but in the number of instances; that is to say, the difference is not in that part of the process for which Bacon has given precise rules, but in a circumstance for which no precise rule can possibly be given. If the learned author of the theory about Jacobinism had enlarged either of his tables a little, his system would have been destroyed. The names of Tom Paine and William Wyndham Grenville would have been sufficient to do the work.
It appears to us, then, that the difference between a sound and unsound induction does not lie in this, that the author of the sound induction goes through the process analysed in the second book of the Novum Organum, and the author of the unsound induction through a different process. They both perform the same process. But one performs it foolishly or carelessly : the other performs it with patience, attention, sagacity, and judgment. Now precepts can do little towards making men patient and attentive, and still less towards making them sagacious and judicious. It is very well to tell men to be on their guard against prejudices, not to believe facts on slight evidence, not to be content with a scanty collection of facts, to put out of their minds the idola which Bacon has so finely described. But these rules are too general to be of much practical use. The question is, What is a prejudice? How long does the incredulity with which I hear a new theory propounded continue to be a wise and salutary incredulity? When does it become an idolum specus, the unreasonable pertinacity of a too sceptical mind? What is slight evidence ? What collection of facts is scanty ? Will ten instances do, or fifty, or a hundred? In how many months would the first human beings who settled on the shores of the ocean have been justified in believing that the moon had an influence on the tides ? After how many experiments would Jenner have been justified in believing that he had discovered a safeguard against the small-pox? These are questions to which it would be most desirable to have a
precise answer; but, unhappily, they are questions to which no precise answer can be returned.
We think then that it is possible to lay down accurate rules, as Bacon has done, for the performing of that part of the inductive process which all men perform alike; but that these rules, though accurate, are not wanted, because in truth they only tell us to do what we are all doing. We think that it is impossible to lay down any precise rule for the performing of that part of the inductive process which a great experimental philosopher performs in one way, and a superstitious old woman in another.
On this subject, we think, Bacon was in an error. He certainly attributed to his rules a value which did not belong to them. He went so far as to say, that, if his method of making discoveries were adopted, little would depend on the degree of force or acuteness of any intellect; that all minds would be reduced to one level, that his philosophy resembled a compass or a rule which equalises all hands, and enables the most unpractised person to draw a more correct circle or line than the best draftsmen can produce without such aid.* This really seems to us as extravagant as it would have been in Lindley Murray to announce that every body who should learn his Grammar would write as good English as Dryden, or in that very able writer, the Archbishop of Dublin, to promise that all the readers of his Logic would reason like Chillingworth, and that all the readers of his Rhetoric would speak like Burke. That Bacon was altogether mistaken as to this point will now hardly be disputed. His philosophy has flourished during two hundred years, and has produced none of this levelling. The interval between a man of talents and a dunce is as wide as ever; and is never more clearly discernible than when they engage in researches which require the constant use of induction.
It will be seen that we do not consider Bacon's ingenious analysis of the inductive method as a very useful performance. Bacon was not, as we have already said, the inventor of the inductive method. He was not even the person who first analysed the inductive method correctly, though he undoubtedly analysed it more minutely than any who preceded him. He was not the person who first showed that by the inductive method alone new truth could be discovered. But he was the person who first turned the minds of speculative men, long occupied in verbal disputes, to the discovery of new and useful
* Novum Organum, Præf. and Lib. 1. Aph. 122.