Although human psychological phenomenon and behavior can be analyzed at different levels in psychology, the individual is always an irreducibly natural unit, and the analysis on any level will eventually have to return to the individual person. 在心理学中,尽管人类心理现象和行为可以进行不同水平的分析,但是个体的人总是一个不可还原的自然单元,对任何水平的心理现象的分析最终都要回归到个体的人身上。