C. D. Broad

It appears to me that the best preparation for original work on any philosophic problem is to study the solutions which have been proposed for it by men of genius whose views differ from each other as much as possible. The clash of their opinions may strike a light which will enable us to avoid the mistakes into which they have fallen; and by noticing the strong and weak points of each theory we may discover the direction in which further progress can be made.

C. D. Broad, Five Types of Ethical Theory, London, 1930, pp. 1-2