Mao Tse-Tung, 1937
Mao discusses the relation between knowledge and practice in a foundational text for his thought that draws heavily from Lenin’s writings. He describes rationalism as the view in which reason takes precedent over experience, but castigates this hierarchisation as backwards. It is abstraction, he says, which is founded upon the senses, and the sensate should be the basis for undoing theory as well. He deploys Chinese proverbs in order to criticize theory that cannot or does not expose itself to empirical testing, and advocates for trial and error over ideological imposition. He concludes by remarking that one should not favor right or left in political thought, only that which reflects the materiality of the world and the tutelary experiences which we may have of it.
https://www.marxists.org/reference/archive/mao/selected-works/volume-1/mswv1_16.htm