西季威克调和了直觉主义和功利主义，却无法调和功利主义和利己主义，留下了著名的实践理性二元论。
After all, Sidgwick left the dualism of practical reason for us. He failed to put utilitarianism and egoism together, although he succeeded in unifying intuitionism and utilitarianism.
深入研究西季威克对古典功利主义的发展，有助于我们更好地理解实践理性二元论产生的背景，以期能从新的角度对这一问题做出思考。
Researching Sidgwick's development of classical utilitarianism, we could get more background of dualism of practical reason. It seems could help us find a new way to think this problem.
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