History of Western Philosophy - Bertrand Russell [344]
Locke is the most fortunate of all philosophers. He completed his work in theoretical philosophy just at the moment when the government of his country fell into the hands of men who shared his political opinions. Both in practice and in theory, the views which he advocated were held, for many years to come, by the most vigorous and influential politicians and philosophers. His political doctrines, with the developments due to Montesquieu, are embedded in the American Constitution, and are to be seen at work whenever there is a dispute between President and Congress. The British Constitution was based upon his doctrines until about fifty years ago, and so was that which the French adopted in 1871.
His influence in eighteenth-century France, which was immense, was primarily due to Voltaire, who as a young man spent some time in England, and interpreted English ideas to his compatriots in the Lettres philosophiques. The philosophes and the moderate reformers followed him; the extreme revolutionaries followed Rousseau. His French followers, rightly or wrongly believed in an intimate connection between his theory of knowledge and his politics.
In England this connection is less evident. Of his two most eminent followers, Berkeley was politically unimportant, and Hume was a Tory who set forth his reactionary views in his History of England. But after the time of Kant, when German idealism began to influence English thought, there came to be again a connection between philosophy and politics: in the main, the philosophers who followed the Germans were Conservative, while the Benthamites, who were Radical, were in the tradition of Locke. The correlation, however, is not invariable; T. H. Green, for example, was a Liberal but an idealist.
Not only Locke's valid opinions, but even his errors, were useful in practice. Take, for example, his doctrine as to primary and secondary qualities. The primary qualities are defined as those that are inseparable from body, and are enumerated as solidity, extension, figure, motion or rest, and number. The secondary qualities are all the rest: colours, sounds, smells, etc. The primary qualities, he maintains, are actually in bodies; the secondary qualities, on the contrary, are only in the percipient. Without the eye, there would be no colours; without the ear, no sounds, and so on. For Locke's view as to secondary qualities there are good grounds—jaundice, blue spectacles, etc. But Berkeley pointed out that the same arguments apply to primary qualities. Ever since Berkeley, Locke's dualism on this point has been philosophically out of date. Nevertheless, it dominated practical physics until the rise of quantum theory in our own day. Not only was it assumed, explicitly or tacitly, by physicists, but it proved fruitful as a source of many very important discoveries. The theory that the physical world consists only of matter in motion was the basis of the accepted theories of sound, heat, light, and electricity. Pragmatically, the theory was useful, however mistaken it may have been theoretically. This is typical of Locke's doctrines.
Locke's philosophy, as it appears in the Essay, has throughout certain merits and certain demerits. Both alike were useful: the demerits are such only from a theoretical standpoint. He is always sensible, and always willing to sacrifice logic rather than become paradoxical. He enunciates general principles which, as the reader can hardly fail to perceive, are capable of leading to strange consequences; but whenever the strange consequences seem about to appear, Locke blandly refrains from drawing them. To a logician this is irritating; to a practical man, it is a proof of a sound judgment. Since the world is what it is, it is clear that valid reasoning from sound principles cannot lead to error; but a principle may be so nearly true as to deserve theoretical respect, and yet may lead to practical consequences which we feel to be absurd. There is therefore a justification for common sense in philosophy, but only as showing that our theoretical principles cannot be