Though this is a tangential topic to this essay, and a subject that one can write an entire essay about, it is worth drawing attention to the similarities that Diotima’s theory has to the modern evolutionary approach to psychology. For Diotima, the core desire that gives rise to the phenomenon of eros is the desire for immortality. This is something that all animals and humans have, and for humans it seems to seep into every action they do: “but I believe that all do all things for the sake of immortal virtue and a famous reputation of that sort; and the better they are, so much the more is it thus; for they love the immortal” (Symposium, 208 D)
The basic premise of evolutionary psychology is that life evolved from basic units that had the tendency to survive as long as possible by engendering copies of themselves. For humans and animals, the basic units that seek immortality are genes. Thus, whatever behavior in a human would encourage the survival of some genes it carries (whether by helping itself, helping other people and animals who share those genes, or by reproducing and thus ensuring further survival of those genes, etc.) is the expected more probable behavior. For example, the genes make the human that carries them more often than not seek an environment in which he can engender further copies of them. Here also in evolutionary psychology we can make the same connection to beauty that Plato makes. We would expect that humans would consider environments suitable to survival and reproduction more beautiful and desirable, since there they can engender copies of their genes, and help them partake in immortality. That’s exactly what studies seem to show across human cultures (see for example paintings of fertile African savannahs that are considered beautiful across most human cultures, and not by coincidence it is a place very suitable for survival and reproduction of humans).
Another similarity is the concept of giving birth through body and giving birth through ideas. For most animals the evolutionary basic element is the bodily gene. But since humans have developed intellection, there is now a new kind of entity that can survive and reproduce in us. Those are ideas. An idea can come into being, and then continue to exist by moving from person to person. There is also a kind of evolutionary pressure on ideas. Some fade away after days, others survive for millennia. There is a whole theory about this, and I think Richard Dawkins is the first to write about them, coining the term meme.
This are just some surface thoughts, but my intuition is that the similarities run very deep, since both have the same core principle at work – immortality, and partaking in that through engendering.