In this paper, I show that Aristophanes’s speech in Plato’s Symposium is tied into an interesting and hitherto unexplored web of ideas in Plato’s ethics and psychology. The poet’s analysis of erōs as ‘leading us to what “belongs” (the oikeion)’ (193d2) and as ‘restoring us in our “original nature” (archaia phusis)’ (193d4) is not a mere negative contribution that renders him a ‘target for Diotima’s fire’ (Dover). Rather, he unwittingly communicates central ethical and psychological ideas which we find developed in (...) key passages of Plato’s dialogues. What is interesting is that Diotima in a curious passage seems to dismiss his contribution of the oikeion as unrelated to our good (agathon) and irrelevant to the analysis of desire (205d10–206a1). I argue that this interpretation of Diotima’s response to Aristophanes, which would render her position an ethical anomaly in Plato’s dialogues, should be rejected. Instead, it is more plausible to read her response as proposing a revisionary conception of the oikeion, relying on the idea that our agathon is our true oikeion. In addition, I tentatively suggest that the theory of psychic pregnancy may be seen as presenting the agathon of wisdom of virtue produced in the ascent as an oikeion. Just as fascinating as Diotima’s stance on the oikeion is the question how her teachings relate to the concept of an archaia phusis of the soul. The idea that the soul’s self-perfection constitutes a return to a temporally prior condition of excellence, which in two places other than the Symposium (Republic X, Timaeus) is called the ‘archaia phusis’, is pervasive and centrally important to Plato’s psychology. I address the question whether Diotima’s ascent passage constitutes a psychological anomaly in portraying self-perfection as unrelated to the concept of the archaia phusis. I argue that an answer to this depends on the stance we take on the Symposium’s position regarding the immortality of the soul. While a reading that posits a rejection of immortality in the Symposium must indeed deny a role for the concept in Diotima’s speech, I show that a reading allowing for immortality as a theoretical commitment in the background has an interesting interpretative option: along with Timaeus 90d5, it may fruitfully interpret the ascent as an ordering of the soul ‘in accordance with its archaia phusis’. (shrink)