 What is this nature that is thus contrasted with matters of opinion or convention? It is, in the first instance, human nature, as witnessed by Cicero’s statement that ‘we’ are born for justice. We all belong to the same species, and to that extent are all alike (1.29), in particular in our possession of reason, which distinguishes us from other creatures (1.30). This explains the sense of mutual fellowship and union between human beings (1.28) and means that we are formed by nature to share justice and impart it to all (1.33). This does not mean that we necessarily do this. Nature is itself a normative concept, so humans can fail to live up to their own nature, corrupted by the effects of bad habit and opinion (1.29, 1.33). Nonetheless, Cicero argues, if one considers the endowments that humans share, one will conclude that justice is the natural human condition.