On Contradiction by Mao Zedong

An essay asserting that contradiction is the fundamental driving force in all phenomena, arguing that every thing and process contains opposing aspects whose interaction produces change; it distinguishes the universal from the particular, principal from secondary contradictions, and antagonistic from non‑antagonistic forms, emphasizing that concrete analysis of the specific conditions and the principal aspect of a contradiction is necessary for correct theory and effective practice, and that knowledge develops through engagement with and resolution of these contradictions.