History of Modern Philosophy. Richard Falckenberg
Читать онлайн книгу.
but are archetypal for reality and need no confirmation from experience. The connexion constituted by our understanding between the ideas crime and punishment (e. g., the proposition: crime deserves punishment) is valid, even though no crime had ever been committed, and none ever punished. Existence is not at all involved in universal propositions; "general knowledge lies only in our own thoughts, and consists barely in the contemplation of our own abstract ideas" and their relations. The truths of mathematics and ethics are both universal and certain, while in natural science single observations and experiments are certain, but not general, and general propositions are only more or less probable. Both the particular experiments and the general conclusions are of great value under certain circumstances, but they do not meet the requirements of comprehensive and certain knowledge.
The extent of our knowledge is very limited—much less, in fact, than that of our ignorance. For our knowledge reaches no further than our ideas, and the possibility of perceiving their agreements. Many things exist of which we have no ideas—chiefly because of the fewness of our senses and their lack of acuteness—and just as many of which our ideas are only imperfect. Moreover, we are often able neither to command the ideas which we really possess, or at least might attain, nor to perceive their connexions. The ideas which are lacking, those which are undiscoverable, those which are not combined, are the causes of the narrow limits of human knowledge.
There are two ways by which knowledge may be extended: by experience, on the one hand, and, on the other, by the elevation of our ideas to a state of clearness and distinctness, together with the discovery and systematic arrangement of those intermediate ideas which exhibit the relation of other ideas, in themselves not immediately comparable. The syllogism, as an artificial form, is of little value in the perception of the agreements between these intermediate and final terms, and of none whatever in the discovery of the former. Analytical and identical propositions which merely explicate the conception of the subject, but express nothing not already known, are, in spite of their indefeasible certitude, valueless for the extension of knowledge, and when taken for more than verbal explanations, mere absurdities. Even those most general propositions, those "principles" which are so much talked of in the schools, lack the utility which is so commonly ascribed to them. Maxims are, it is true, fit instruments for the communication of knowledge already acquired, and in learned disputations may perform indispensable service in silencing opponents, or in bringing the dispute to a conclusion; but they are of little or no use in the discovery of new truth. It is a mistake to believe that special cases (as 5 = 2 + 3, or 5 = 1 + 4) are dependent on the truth of the abstract rule (the whole is equal to the sum of its parts), that they are confirmed by it and must be derived from it. The particular and concrete is not only as clear and certain as the general maxim, but better known than this, as well as earlier and more easily perceived. Nay, further, in cases where ideas are confused and the meanings of words doubtful, the use of axioms is dangerous, since they may easily lend the appearance of proved truth to assertions which are really contradictory.
Between the clear daylight of certain knowledge and the dark night of absolute ignorance comes the twilight of probability. We find ourselves dependent on opinion and presumption, or judgment based upon probability, when experience and demonstration leave us in the lurch and we are, nevertheless, challenged to a decision by vital needs which brook no delay. The judge and the historian must convince themselves from the reports of witnesses concerning events which they have not themselves observed; and everyone is compelled by the interests of life, of duty, and of eternal salvation to form conclusions concerning things which lie beyond the limits of his own perception and reflective thought, nay, which transcend all human experience and rigorous demonstration whatever. To delay decision and action until absolute certainty had been attained, would scarcely allow us to lift a single finger. In cases concerning events in the past, the future, or at a distance, we rely on the testimony of others (testing their reports by considering their credibility as witnesses and the conformity of the evidence to general experience in like cases); in regard to questions concerning that which is absolutely beyond experience, e.g., higher orders of spirits, or the ultimate causes of natural phenomena, analogy is the only help we have. If the witnesses conflict among themselves, or with the usual course of nature, the grounds pro and con must be carefully balanced; frequently, however, the degree of probability attained is so great that our assent is almost equivalent to complete certainty. No one doubts—although it is impossible for him to "know,"—that Caesar conquered Pompey, that gold is ductile in Australia as elsewhere, that iron will sink to-morrow as well as to-day. Thus opinion supplements the lack of certain knowledge, and serves as a guide for belief and action, wherever the general lot of mankind or individual circumstances prevent absolute certitude.
Although in this twilight region of opinion demonstrative proofs are replaced merely by an "occasion" for "taking" a given fact or idea "as true rather than false," yet assent is by no means an act of choice, as the Cartesians had erroneously maintained, for in knowledge it is determined by clearly discerned reasons, and in the sphere of opinion, by the balance of probability. The understanding is free only in combining ideas, not in its judgment concerning the agreement or the repugnancy of the ideas compared; it lies within its own power to decide whether it will judge at all, and what ideas it will compare, but it has no control over the result of the comparison; it is impossible for it to refuse its assent to a demonstrated truth or a preponderant probability.
In this recognition of objective and universally valid relations existing among ideas, which the thinking subject, through comparisons voluntarily instituted, discovers valid or finds given, but which it can neither alter nor demur to, Locke abandons empirical ground (cf. p. 155) and approaches the idealists of the Platonizing type. His inquiry divides into two very dissimilar parts (a psychological description of the origin of ideas and a logical determination of the possibility and the extent of knowledge), the latter of which is, in Locke's opinion, compatible with the former, but which could never have been developed from it. The rationalistic edifice contradicts the sensationalistic foundation. Locke had hoped to show the value and the limits of knowledge by an inquiry into the origin of ideas, but his estimate of this value and these limits cannot be proved from the a posteriori origin of ideas—it can only be maintained in despite of this, and stands in need of support from some (rationalistic) principle elsewhere obtained. Thinkers who trace back all simple ideas to outer and inner perception we expect to reject every attempt to extend knowledge beyond the sphere of experience, to declare the combinations of ideas which have their origin in sensation trustworthy, and those which are formed without regard to perception, illusory; or else, with Protagoras, to limit knowledge to the individual perceiving subject, with a consequent complete denial of its general validity. But exactly the opposite of all these is found in Locke. The remarkable spectacle is presented of a philosopher who admits no other sources of ideas than perception and the voluntary combination of perceptions, transcending the limits of experience with proofs of the divine existence, viewing with suspicion the ideas of substance formed at the instance of experience, and reducing natural science to the sphere of mere opinion; while, on the other hand, he ascribes reality and eternal validity to the combinations of ideas formed independently of perception, which are employed by mathematics and ethics, and completely abandons the individualistic position in his naïve faith in the impregnable validity of the relations of ideas, which is evident to all who turn their attention to them. The ground for the universal validity of the relations among ideas as well as of our knowledge of them, naturally lies not in their empirical origin (for my experience gives information to me alone, and that only concerning the particular case in question), but in the uniformity of man's rational constitution. If two men really have the same ideas—not merely think they have because they use similar language—it is impossible, according to Locke, that they should hold different opinions concerning the relation of their ideas. With this conviction, that the universal validity of knowledge is rooted in the uniformity of man's rational constitution, and the further one, that we attain certain knowledge only when things conform to our ideas, Locke closely approaches Kant; while his assumption of a fixed order of relations among ideas, which the individual understanding cannot refuse to recognize, and the typical character assigned to mathematics, associate him with Malebranche and Spinoza. In view of these points of contact with the rationalistic school and his manifold dependence on its founder, we may venture the paradox, that Locke may not only be termed a Baconian with Cartesian leanings,