The Plato Cult
Berkeley is one of those philosophers who are always arguing, and he gave a number of arguments for abridging the Cartesian world-view to the exclusive benefit of its mental half. Once he had done it, everyone could see, even if they had not seen before, that Cartesianism had begged for an idealist abridgement, and that it had got it from Berkeley.
There was only one catch; but it was a rather serious one. This was that no one could believe the world-view to which those arguments of Berkeley led. Or rather, no one could even mention what this world-view was, without smiling: much as Cicero says that no two augurs could meet without smiling. It was all very well to have the 'materialists, atheists, etc.,' driven from the field by force of argument: philosophers were in favour of that, almost to a man. But not at this ridiculous price!
What was to be done? No one thought seriously, at the times of which I am speaking, of going right back beyond the Cartesian starting-points, of dualism in metaphysics, and representationism in epistemology. The future of philosophy was therefore fixed: it had to be idealistic. Reid, and then Hamilton, tried indeed to stem the idealist tide, but their attempt was half-hearted, and in any case it came too late: idealism has so powerful a wish behind it that, once you have conquered your common sense and actually tried the stuff, it is almost impossible to break the habit. Of course idealism did not at once sweep the field clear of all rivals. The history of thought is never neat, and there are always stragglers. Hence the amputative surgery, which Berkeley had performed on Descartes (via Locke), had often to be done over again, even in the middle of the nineteenth century, on stray autodidacts such as Herbert Spencer, when they ignorantly wandered on to the field of battle. But for the professional philosophers the great desideratum, after Berkeley, was simply this: a version of idealism which was not, like his, a proper object of general derision.
It was precisely this which Kant appeared, at least, to supply, and the philosophical profession, almost as one man, and with inexpressible relief, closed with his offer. This was the unique service which Kant rendered to modern idealism: he seemed to prove, in his own person, that you could be an idealist without looking a complete fool. That is what entitles Kant to Nietzsche's superb description of him, as 'this catastrophic spider.' Berkeley's web had caught no one; but Kant's web, promising idealism-without-subjectivity, proved irresistibly attractive, and for the next 150 years almost no philosopher escaped it.
This 'objective' idealism was not reached by argument: argument had nothing to do with it. It was reached by the biggest, though also the simplest, bluff ever tried. Kant simply said, in effect, 'Let us say that the physical universe is objective as well as ideal: that should satisfy all parties (or at least stagger them).' It did, too. You can easily, as the poet sang, 'vanquish Berkeley by a grin,' and every person of sense does so. Besides, Berkeley's ghostly vocation had always left a suspicion of interestedness hanging over his ghostly philosophy. But an eighteenth-century German professor, with no clerical axe to grind, and with many apparent and some real marks of intellectual authority, who informs you that space is empirically real (even if it is also transcendentally ideal), is certainly no laughing matter. He couldn't be joking, could he? (Or equivocating? He couldn't possibly mean, by 'objective' and 'empirically real,' just 'non-idiosyncratic' or 'believed in by everyone,' could he? Surely he couldn't, could he?)