Socrates continues his discussion of Love by restating an account given to him by a woman named Diotima. He claims that he once held the opinions expressed by Agathon and that Diotima convinced him he was mistaken through a series of questions similar to those Socrates has just asked Agathon. Thus, Socrates picks up where he left off in his dialogue with Agathon, only he now presents himself as being in Agathon's position, and presents Diotima as taking his role.
Having been convinced that Love is not beautiful or good, Socrates asks Diotima if that means Love is ugly and bad. Diotima argues that not everything must be either one thing or its opposite. For instance, having unjustified true opinions is neither wisdom nor ignorance. Wisdom consists in justified true opinions, but one would hardly call a true opinion ignorant.
Diotima points out that, in spite of himself, Socrates has denied that Love is a god altogether. They have concluded that Love is not good and beautiful because he is in need of good and beautiful things. No one would deny that a god is both happy and beautiful, and yet Love seems to be neither of these things. Then, Socrates asks, does that mean that Love is mortal? Diotima replies once more that not everything must be one thing or its opposite. Love is neither mortal nor immortal, but is a spirit, which falls somewhere between being a god and being human.
Spirits, Diotima explains, serve as intermediaries between gods and humans. They convey prayers and sacrifices from humans to gods, and send gifts and commands from gods to humans. The gods never communicate directly with humans, but only through the medium of spirits, who are the source of all divination. There are many kinds of spirits, Love being but one.
Love was conceived at a feast to celebrate the birth of Aphrodite, goddess of love. Resource, the son of Invention, got quite drunk and lay down to sleep in the garden of Zeus. Poverty crept up on Resource and slept with him, hoping to relieve her lack of resources by having a child with Resource. Love is the child that Poverty conceived by Resource. Because he was conceived on Aphrodite's birthday, Love has become her follower, and has become in particular a lover of beauty. As the child of Resource and Poverty, Love is always poor, and, far from being sensitive, he is very tough, sleeping out of doors on the rough ground. Like his mother, he is always in a state of need, but like his father, he can scheme to get what he wants. Being neither mortal nor immortal, Love may shoot into life one day only to die the next and then return to life the following day.
Love is also a great lover of wisdom. None of the gods love wisdom because they are already wise and do not need wisdom, nor do the ignorant love wisdom since they do not realize that they need wisdom. Love falls between ignorance and wisdom because his father, Resource, is both wise and resourceful, while his mother, Poverty, is neither. Diotima suggests that Socrates' earlier grandiose claims about Love's greatness were directed at the object of love and not the lover himself. Beauty, perfection, and so on, are the qualities of the things we love, but the lover himself is not at all like this.
Diotima is not known to be a historical figure, and the way in which she is introduced suggests that she is almost certainly just a literary device. Plato's most familiar method of laying out philosophical ideas is through dialogue, and so he needs to find someone for Socrates to interact with. Agathon has just bowed out of the conversation, so Plato invents the character of Diotima in order to carry on the dialogue. Also, Plato wants to set Socrates up as the perfect exemplar of Love, one who is always searching for wisdom rather than someone who has wisdom. Socrates is famous for his remark in the Apology that he is only wiser than other men in that he knows that he knows nothing. Thus, Socrates himself cannot claim to know the truth about Love. Instead, Plato introduces Diotima as a prophetic figure who does know the truth about Love and who can lead Socrates toward it. Diotima is introduced to perpetuate the dialogue and to speak from a position of authority about Love.
We recall that Agathon's speech identified love in many way with himself. It was beautiful, wise, young, and the object of desire, according to his speech. Socrates reverses Agathon's claim, suggesting that Agathon, and the love he speaks of, is not Love itself, but is rather the object of Love's desire. As the passive partner in his relationship with Pausanias, Agathon is quite literally the "loved one."
We should note, then, that Socrates here sets himself up as the exemplar of Love. Love seeks wisdom, lives simply and is quite poor, he is tough and brave, according to Socrates' account, and all these qualities are also true of Socrates. Notably, Socrates calls Love a "lover of wisdom" which in Greek means quite literally a philosopher (philia = "love" and sophia = "wisdom"). Socrates is beginning a move that will be elaborated further by Diotima whereby the philosopher is the perfect exemplar of love, someone who is always seeking and never finding.
As such, this section further builds on the notion that Love is a relational property, one that holds between things rather than holding one thing in particular. Diotima builds a myth to rival that of Aristophanes, suggesting that Love is the go-between between mortals and gods, and that Love is the child of Resource and Poverty, always resourceful, but always in need. Thus, Diotima gives physical embodiment to a relational property by means of a myth. Considering a relation as a thing on its own, distinct from the objects it mediates between can be philosophically problematic, however. The idea of a relation as a messenger spirit makes for a compelling myth, and it does not particularly muddle the philosophy of the Symposium, but in more logically rigorous systems, it becomes difficult to account for relations as things in one's ontology.