Religion and Science from Galileo to Bergson

by J. C. Hardwick

The word critical signifies a particular method of approaching the problem of existence, a method which must be contrasted with that of the speculative philosophy, of which Spinoza and Leibniz are examples.

The critical philosophy, before attempting (as Spinoza had done) to tackle the problem of existence, first attacked the problem of knowledge. Before asking What is the truth? it put the preliminary question, What are the means at man's disposal for reaching the truth? It prefaced all philosophical enquiry by an examination into the nature and scope of human thought. Such was the preparatory investigation which was to place metaphysics upon a secure and scientific foundation. For the new philosophy, the gateway to all sound knowledge is the reflection of the human mind upon itself. "Know thyself," is its advice to the inquiring spirit of man. Here, if anywhere, is to be found the philosopher's stone.

Immanuel Kant.—The celebrated Immanuel Kant was born at Königsberg in 1724, and died in his native town in 1804. Between those dates he lived the industrious and uneventful life of a university professor. The Seven Years' War and the French Revolution left him undisturbed, though not unmoved. He was a man of quiet, regular habits, and his fellow-townsmen would set their clocks by his daily promenade.[23] But the adventurous originality of his thought serves as a contrast to this peaceful picture.

Kant, indeed, laid the foundations of philosophy afresh. With characteristic insight, he went to the very root problem of all, and challenged human thought itself. Before we can know anything, we must first of all demand the credentials of the instrument by which knowledge is gained. Before asking, What do I know? the preliminary question should be, How do I know? Otherwise we cannot say whether we are in a position to give any answer to those ultimate problems, the answers to which constitute philosophy.

It is far from easy to present Kant's criticism of knowledge at once simply and accurately. This philosopher has a not undeserved reputation for obscurity, and had he written in any other language than German, he would perhaps have found no readers.

The Problem of Knowledge.—It had already been realised by the predecessors of Kant that what is called "sense-experience" is a less simple process than it seems, and that our senses cannot be said to reveal to us any object as it actually is. John Locke himself was not the first to point out that the so-called "secondary qualities" of any material object (i.e. colour, taste, etc.) are produced just as much by the person who perceives, as by the object which is perceived. Galileo, Descartes, and Hobbes, besides others, had been aware of this fact, which indeed becomes evident to the most superficial analysis of sense-experience.

The "primary qualities," i.e. density, extension, etc., continued to be regarded as subsisting in the objects themselves, and independently of any perceiving consciousness. But even this view did not prove permanent, and it was the episcopal philosopher, George Berkeley (1685-1753) who demonstrated in his New Theory of Vision that not even these qualities could rightly be regarded as subsisting independently.

Thus it had already been realised, long before Kant wrote his Critique of Pure Reason (published, 1781), that our senses are far from revealing to us things as they are; it is only the appearances of things and not the things themselves that the senses present to us. Indeed, as is well known, the Scotch philosopher David Hume (1711-1776), who was a master in the art of raising problems, extended this line of criticism until it reached to pure scepticism. He put the question, If all our knowledge is derived from sense-experience, and if sense-experience only supplies us with appearance and not reality, what degree of trustworthiness can there be in human knowledge? And he was not afraid to give the logical answer—None. Hume may thus be said to have brought things to an impasse. As a matter of fact, what he had done was to refute Locke's theory of knowledge (i.e. that it is derived entirely from sense-experience) by means of a reductio ad absurdum.

The Kantian Criticism.—Kant says that it was Hume who "awoke him from his dogmatic slumbers." By this he meant that Hume made him realise that it was no use indulging in philosophic speculation generally, or listening to the speculations of others, until "the Problem of Knowledge" was satisfactorily solved. To this problem Kant applied himself. And recognising Locke to be the fons et origo malorum, he subjected his theory of human knowledge to a close analysis, and exposed it as being fallacious.

Far from sense-experience being responsible for all our knowledge, Kant proved that important elements of knowledge are quite independent of sense-experience; especially was this so in the case of certain mathematical propositions. (Hence the question, How is pure mathematics possible? was put by Kant at the beginning of his philosophy.)