This paper examines John Maynard Keynes’s ethical theory and how it relates to his politico-economic thought. Keynes’s ethical theory represents an attack on all general rules. Since capitalism is a rule-based social system, Keynes’s ethical theory is incompatible with capitalism. And since socialism rejects the general rules of private property, the Keynesian ethical theory is consistent with socialism. The unexplored evidence presented here confirms Keynes advocated a consistent form of non-Marxist socialism from no later than 1907 until his death in 1946. However, Keynes’s ethical theory is flawed because it is based on his defective logical theory of probability. Consequently, Keynes’s ethical theory is not a viable ethical justification for socialism.
