  Such external testimony — albeit from an unsympathetic source — presents a minor puzzle in the interpretation of Mohist thought, for the texts preserved in the Mozi do not directly advocate self-sacrificing altruism, and at least one clearly rejects it. The same Zhuangzi passage tells us that different groups of Mohists disagreed strongly concerning the details of Mohist doctrine; perhaps this was one of the issues about which they differed.