[Footnote 1: According to the faculties of the soul, memory, imagination, and understanding, three principal sciences are distinguished; history, poesy, and philosophy. Of the three objects of the latter, "nature strikes the mind with a direct ray, God with a refracted ray, and man himself with a reflected ray." Theology is natural or revealed. Speculative (theoretical) natural philosophy divides into physics, concerned with material and efficient causes, and metaphysics, whose mission, according to the traditional view, is to inquire into final causes, but in Bacon's own opinion, into formal causes; operative (technical) natural philosophy is mechanics and natural magic. The doctrine concerning man comprises anthropology (including logic and ethics) and politics. This division of Bacon was still retained by D'Alembert in his preliminary discourse to the Encyclopédie.]
[Footnote 2: Cf. on Bacon, K. Fischer, 2d ed., 1875; Chr. Sigwart, in the Preussische Jahrbücher, 1863 and 1864, and in vol. ii. of his Logik; H. Heussler, Baco und seine geschichtliche Stellung, Breslau, 1889. [Adamson, Encyclopedia Britannica, 9th. ed., vol. iii. pp. 200-222; Fowler, English Philosophers Series, 1881; Nichol, Blackwood's Philosophical Classics, 2 vols., 1888-89.—TR.] Bacon's merit was threefold: he felt more forcibly and more clearly than previous thinkers the need of a reform in science; he set up a new and grand ideal—unbiased and methodical investigation of nature in order to mastery over nature; and he gave information and directions as to the way in which this goal was to be attained, which, in spite of their incompleteness in detail, went deep into the heart of the subject and laid the foundation for the work of centuries.[1] His faith in the omnipotence of the new method was so strong, that he thought that science for the future could almost dispense with talent. He compares his method to a compass or a ruler, with which the unpractised man is able to draw circles and straight lines better than an expert without these instruments.
[Footnote 1: His detractors are unjust when they apply the criterion of the present method of investigation and find only imperfection in an imperfect beginning.]
All science hitherto, Bacon declares, has been uncertain and unfruitful, and does not advance a step, while the mechanic arts grow daily more perfect; without a firm basis, garrulous, contentious, and lacking in content, it is of no practical value. The seeker after certain knowledge must abandon words for things, and learn the art of forcing nature to answer his questions. The seeker after fruitful knowledge must increase the number of discoveries, and transform them from matters of chance into matters of design. For discovery conditions the power, greatness, and progress of mankind. Man's power is measured by his knowledge, knowledge is power, and nature is conquered by obedience—scientia est potentia; natura parendo vincitur.
Bacon declares three things indispensable for the attainment of this power-giving knowledge: the mind must understand the instruments of knowledge; it must turn to experience, deriving the materials of knowledge from perception; and it must not rise from particular principles to the higher axioms too rapidly, but steadily and gradually through middle axioms. The mind can accomplish nothing when left to itself; but undirected experience alone is also insufficient (experimentation without a plan is groping in the dark), and the senses, moreover, are deceptive and not acute enough for the subtlety of nature—therefore, methodical experimentation alone, not chance observation, is worthy of confidence. Instead of the customary divorce of experience and understanding, a firm alliance, a "lawful marriage," must be effected between them. The empiricists merely collect, like the ants; the dogmatic metaphysicians spin the web of their ideas out of themselves, like the spiders; but the true philosopher must be like the bee, which by its own power transforms and digests the gathered material.
As the mind, like a dull and uneven mirror, by its own nature distorts the rays of objects, it must first of all be cleaned and polished, that is, it must be freed from all prejudices and false notions, which, deep-rooted by habit, prevent the formation of a true picture of the world. It must root out its prejudices, or, where this is impossible, at least understand them. Doubt is the first step on the way to truth. Of these Phantoms or Idols to be discarded, Bacon distinguishes four classes: Idols of the Theater, of the Market Place, of the Den, and of the Tribe. The most dangerous are the idola theatri, which consist in the tendency to put more trust in authority and tradition than in independent reflection, to adopt current ideas simply because they find general acceptance. Bacon's injunction concerning these is not to be deceived by stage-plays (i.e., by the teachings of earlier thinkers which represent things other than they are); instead of believing others, observe for thyself! The idola fori, which arise from the use of language in public intercourse, depend upon the confusion of words, which are mere symbols with a conventional value and which are based on the carelessly constructed concepts of the vulgar, with things themselves. Here Bacon warns us to keep close to things. The idola specus are individual prepossessions which interfere with the apprehension of the true state of affairs, such as the excessive tendency of thought toward the resemblances or the differences of things, or the investigator's habit of transferring ideas current in his own department to subjects of a different kind. Such individual weaknesses are numberless, yet they may in part be corrected by comparison with the perceptions of others. The idola tribus, finally, are grounded in the nature of the human species. To this class belong, among others, illusions of the senses, which may in part be corrected by the use of instruments, with which we arm our organs; further, the tendency to hold fast to opinions acceptable to us in spite of contrary instances; similarly, the tendency to anthropomorphic views, including, as its most important special instance, the mistake of thinking that we perceive purposive relations everywhere and the working of final causes, after the analogy of human action, when in reality efficient causes alone are concerned. Here Bacon's injunction runs, not to interpret natural phenomena teleologically, but to explain them from mechanical causes; not to narrow the world down to the limits of the mind, but to extend the mind to the boundaries of the world, so that it shall understand it as it really is.
To these warnings there are added positive rules. When the investigator, after the removal of prejudices and habitual modes of thought, approaches experience with his senses unperverted and a purified mind, he is to advance from the phenomena given to their conditions. First of all, the facts must be established by observation and experiment, and systematically arranged,[1] then let him go on to causes and laws.[2] The true or scientific induction[3] thus inculcated is quite different from the credulous induction of common life or the unmethodical induction of Aristotle. Bacon emphasizes the fact that hitherto the importance of negative instances, which are to be employed as a kind of counter-proof, has been completely overlooked, and that a substitute for complete induction, which is never attainable, may be found, on the one hand, in the collection of as many cases as possible, and, on the other, by considering the more important or decisive cases, the "prerogative instances." Then the inductive ascent from experiment to axiom is to be followed by a deductive descent from axioms to new experiments and discoveries. Bacon rejects the syllogism on the ground that it fits one to overcome his opponent in disputation, but not to gain an active conquest over nature. In his own application of these principles of method, his procedure was that of a dilettante; the patient, assiduous labor demanded for the successful promotion of the mission of natural investigation was not his forte. His strength lay in the postulation of problems, the stimulation and direction of inquiry, the discovery of lacunae and the throwing out of suggestions; and many ideas incidentally thrown off by him surprise us by their ingenious anticipations of later discoveries. The greatest defect in his theory was his complete failure to recognize the services promised by mathematics to natural science. The charge of utilitarianism, which has been so broadly made, is, on the contrary, unjust. For no matter how strongly he emphasizes the practical value of knowledge, he is still in agreement with those who esteem the godlike condition of calm and cheerful acquaintance with truth more highly than the advantages to be expected from it; he desires science to be used, not as "a courtezan for pleasure," but "as a spouse for generation, fruit and comfort," and—leaving entirely out of view his isolated acknowledgments of the inherent value of knowledge—he conceives its utility wholly in the comprehensive and noble sense that the pursuit of science, from which as such all narrow-minded regard for direct practical application must keep aloof, is the most important lever for the advancement of human culture.
[Footnote 1: Bacon illustrates the method by the explanation of heat. The results of experimental observation are to be arranged in three tables. The table of presence contains many different cases in which heat occurs; the table of absence, those in which, under circumstances otherwise the same, it is wanting; the table of degrees or comparison enumerates phenomena whose increase and decrease accompany similar variations in the degree of heat. That which remains after the exclusion now to be undertaken (of that which cannot be the nature or cause of heat), yields as a preliminary result or commencement of interpretation (as a "first vintage"), the definition of heat: "a motion, expansive, restrained, and acting in its strife upon the smaller particles of bodies.">[
[Footnote 2: This goal of Baconian inquiry is by no means coincident with that of exact natural science. Law does not mean to him, as to the physical scientist of to-day, a mathematically formulated statement of the course of events, but the nature of the phenomenon, to be expressed in a definition (E. König, Entwickelung des Causalproblems bis Kant, 1883, pp. 154-156). Bacon combines in a peculiar manner ancient and modern, Platonic and corpuscular fundamental ideas. Rejecting final causes with the atomists, yet handing over material and efficient causes (the latter of which sink with him to the level of mere changing occasional causes) to empirical physics, he assigns to metaphysics, as the true science of nature, the search for the "forms" and properties of things. In this he is guided by the following metaphysical presupposition: Phenomena, however manifold they may be, are at bottom composed of a few elements, namely, permanent properties, the so-called "simple natures," which form, as it were, the alphabet of nature or the colors on her palette, by the combination of which she produces her varied pictures; e. g., the nature of heat and cold, of a red color, of gravity, and also of age, of death. Now the question to be investigated becomes, What, then, is heat, redness, etc.? The ground essence and law of the natures consist in certain forms, which Bacon conceives in a Platonic way as concepts and substances, but phenomenal ones, and, at the same time, with Democritus, as the grouping or motion of minute material particles. Thus the form of heat is a particular kind of motion, the form of whiteness a determinate arrangement of material particles. Cf. Natge, Ueber F. Bacons Formenlehre, Leipsic, 1891, in which Heussler's view is developed in more detail. [Cf. further, Fowler's Bacon, English Philosophers Series, 1881, chap. iv.—TR.]
[Footnote 3: The Baconian method is to be called induction, it is true, only in the broad sense. Even before Sigwart, Apelt, Theorie der Induction, 1854, pp. 151, 153, declared that the question it discussed was essentially a method of abstraction. This, however, does not detract from the fame of Bacon as the founder, of the theory of inductive investigation (in later times carefully elaborated by Mill).]