From an engaging essay on Isaiah Berlin

'"Two Concepts" is a classic source for what has become a standard manoeuvre against all kinds of threat to the conceptual status quo. The trick is to accuse the challenger of pig-headedness-of overweening dogmatism and addiction to a single pattern of explanation. Berlin unveiled the tactic in his first paragraph, deriding "those who put their faith in some immense, world-transforming phenomenon, like the final triumph of reason or the proletarian revolution." The trouble with rationalists and Marxists and other enemies of liberal freedom, he seemed to suggest, was not so much that they were mistaken as that they were crashing bores, always worrying at the same old worn-out bone. Berlin invited us to smile with him at all the one-track thinkers with their sickly fixations on "some super-personal entity-a state, a class, a nation, or the march of history itself," or "some single formula... whereby all the diverse ends of men can be harmoniously realised."

Berlin's confidence deserted him, however, when he tried to explain exactly what was wrong with conceptual monism. He declared that it was "not reconcilable with the principles accepted by those who respect the facts," or again, that it was "not compatible with empiricism." This was a feeble ploy, however, and a question-begging one: facts and experience cannot speak for themselves, and Berlin's boring monomaniacs would always be able to claim them for their side rather than his. Appeals to "the world that we encounter in ordinary experience," and warnings against anything that "it would be eccentric to say" cannot have much authority when deep or even tragic differences are in play. Berlin's mountainous labours have produced a plaintive little mouse, imploring us to respect traditions, especially when they are, as he put it, "so long and widely accepted that their observance has entered into the very conception of what it is to be a normal human being." "Two Concepts" was a magisterial performance, but not without pathos: by the end of it the master is left intellectually becalmed, up a conceptual creek without a paddle.'