Because support-bargaining and money-bargaining are situation related the word ‘ﬁt’ has been used to designate the way we understand what is desirable or relevant to situations. The situations are themselves concepts derived through support-bargaining, so that the whole process of selection and valuation becomes an assessment of how everything ﬁts together. This chapter investigates symmetry and the sense of symmetry as the way humans ﬁt everything together. Symmetry appears to be not just the way humans ﬁt everything together, but the way the universe ﬁts together, including the ﬁt of humans into the universe of which they are a part. Symmetry links bargaining theory to some basic traits of humanity and links it also to basic traits of the universe. Consistency with ideas of symmetry adds to the probability that bargaining theory is a realistic account of social processes.