 The issue is then shown to have particular pertinence when religion is to the forefront. In his response to Balbus, Cotta, who also held the Roman office of priest, picks up on Balbus’ plea, at the end of Book 2, that Cotta support Stoic doctrine, by asserting that by this was no doubt meant that he should uphold the ancestral beliefs about the gods and about religious practice – and, he adds, no discourse will ever turn him away from such beliefs (3.5). As a Roman aristocrat of distinguished ancestry and as a priest, it behooves Cotta to accept ancestral precedent even without rational argument; but, since Balbus is a philosopher, the latter ought to give such argument in defence of his claims (3.6). For Cotta, ancestral authority suffices for his belief that the gods exist (3.7, 3.9), whereas Balbus, since he ‘despises authority’, must fight using reason alone. So, in responding to him, Cotta will pitch his own reason against Balbus’ (3.9).