History is full of examples. How many religions have not perished from ritual sclerosis, how many sciences have not been degraded into pseudo-sciences or games! Logic has been just examinable nonsense for over two thousand years. The present economic chaos in the world has been indirectly brought about by the policy adopted by the professors of economics forty or fifty years ago, to suit their own convenience. For they then decided that they must escape from the unwelcome attentions of the public by becoming more ‘scientific’; _i.e._ they ceased to express themselves in plain language and took to mathematical formulae and curves instead; with the result that the world promptly relapsed into its primitive depths of economic ignorance. So soon as the professors had retired from it, every economic heresy and delusion, which had been exposed and uprooted by Adam Smith, at once revived and flourished. In one generation economics disappeared completely from the public ken and the political world, and the makers of the Peace Treaties of 1919 were so incapable of understanding an economic argument that not even the lucid intelligence of Mr Keynes could dissuade them from enacting the preposterous conditions which rendered impossible the realization of their aims.[A] Nor was it so very long ago that, in order to save the Mathematical Tripos at Cambridge, it had to be recast, because it had degenerated into an intellectual jig-saw puzzle, wholly unrelated to the applications of mathematics to the other sciences. To avoid jealousies, I hasten to add that the University of Oxford, which has organized itself as an asylum for lost causes, skilfully cultivates, by means of its classical and historical studies, a backward-looking bias in its _alumni_. The true ‘Greats’ man is meant to go down indelibly imbued with the conviction that in matters of morals and politics nothing of importance has been discovered or said since Plato and Aristotle, and that nothing else matters. Clearly then we cannot take for granted that in any society knowledge can progress without limits, nor can we count on our academic institutions to save us from stagnation and decay, even in matters of knowledge. All institutions are social mechanisms, and all mechanisms need a modicum of intelligent supervision, in the absence of which they become dangerous engines of destruction. IV