In the Phaedrus Socrates prays to Eros that he may turn Lysias to philosophy as his brother Polemarchus has been turned to it, so that Phaedrus, Lysias’ lover (ho erastȇs autou), may cease wavering between two choices, and simply live for Love with philosophic discourse (all’ haplȏs pros Erȏta meta philosophȏn logȏn ton bion poiȇtai, 257b2-6). The two choices are determined by Lysias’ erotic piece on the one hand, and Socrates’ Palinode on the other. Lysias ‘says (legei) that sexual favours should be granted (hȏs charisteon) to a man who is not in love (mȇ erȏnti) rather than the one who is (mallon ȇ erȏnti, 227c7-8),’ Socrates in his Palinode maintains that true love is free from sex, and that the only way it can be attained is by the lover’s memory being carried to the sight of the Form of beauty at the sight of his beloved’s earthly beauty (253c7-256b7). If Socrates says in the Phaedrus that Phaedrus would devote himself to his love of Lysias ‘with philosophic discourse’ on the condition that the latter turned to philosophy as Polemarchus has been turned to it, this means that when Plato wrote the dialogue, Polemarchus must have made him believe that his memory was carried to the sight of the Forms so acutely, as the memory of the philosopher-lover was carried to the sight of the Form of beauty at the sight of his beloved.
In Republic I Polemarchus has no inkling of the Form of justice when he defines justice as benefiting friends and harming enemies (331d2-334b9), and he does not recollect the Form of justice when he accepts Socrates’ maxim that to harm a friend or anyone else is not the act of a just man (ouk ara tou dikaiou blaptein ergon), but of the opposite (alla tou enantiou), the unjust man (tou adikou, 335d11-12). Socrates himself is at this point far from recollecting the Form of justice. For he arrives at his maxim by claiming that justice (dikaiosunȇ) is human virtue (anthrȏpeia aretȇ, 335c4), and that it is not the function of virtue to harm anybody (335c9-d7), yet he closes Republic I with the words: ‘I know not what justice is (hopote gar to dikaion mȇ oida ho estin), and therefore I am not likely to know (scholȇi eisomai) whether it is or is not a virtue (eite aretȇ tis ousa tunchanei eite kai ou, 354c1-2, tr. Jowett).’
The whole discussion between Socrates and Polemarchus takes place within the framework of mere opinion-making.