In ethics Dühring follows Comte in making sympathy the foundation of morality. In political philosophy he teaches an ethical communism, and attacks the Darwinian principle of struggle for existence. In economics he is best known by his vindication of the American writer H. C. Carey,[5] who attracts him both by his theory of value, which suggests an ultimate harmony of the interests of capitalist and labourer, and also by his doctrine of national political economy, which advocates protection on the ground that the morals and culture of a people are promoted by having its whole system of industry complete within its own borders.