Instead, he argued for the "psychic unity of mankind", a belief that all humans had the same intellectual capacity, and that all cultures were based on the same basic mental principles.
取而代之的，他试图证明“人类心智一致性”，這是一个信念，所有的人类都具有相同的知識能力，以及所有文化都基于相同的基本心智法则。