This from David Boucher’s The Victim of Thought: The Idealist Inheritance:
Idealists and realists were not as antagonistic toward each other as is commonly thought. Harold Joachim, for example, submitted the second chapter of The Nature of Truth to his “friend Bertrand Russell” before the book was published. R. G. Collingwood was a respected figure internationally the conversation of mankind and a very close friend and godfather to the son of the realist E. F. Carritt. Even the younger generation of philosophers opposed to idealism admired Collingwood’s work. A. J. Ayer, against whom Collingwood directed much of An Essay on Metaphysics in an attack on logical positivism, admired his older colleague. Ayer maintained that his esteem for Collingwood came in the 1930s. He admired the style of all of Collingwood’s books but was particularly impressed by the application of his theory of absolute presuppositions in The Idea of Nature Ayer devoted a chapter to Collingwood in his Philosophy in the Twentieth Century, alongside Bertrand Russell, G. E. Moore, Hilary Putnam, and W. V. O. Quine.
Gilbert Ryle, Ayer’s tutor and Collingwood’s successor to the Waynflete chair of metaphysical philosophy, published The Concept of Mind in 1949. Both Ryle and the British idealists were anti-Cartesian. Ryle wanted to deny the mind and body dualism, which was the received orthodoxy. Ryle called it “the ghost in the machine.” Like Oakeshott, Ryle maintained that it is a category error to conjoin or disjoin statements about mental and physical processes as if they are of the same logical type or as if they are species of a genus called experience. The mind cannot be separated from its “overt acts and utterances.” Ryle was more than generous in attributing to his idealist predecessor a significant role in exorcising the ghost in the machine.