Plato

Plato was an ancient Greek philosopher, the student of Socrates. He founded the Academy in Athens and tutored Aristotle. Plato is well known for his Theory of Forms , otherwise known as the Theory of Ideas. According to this theory, the ideal forms which the material things around us represent actually possess within themselves a higher reality. This idea undoubtedly influenced Stevens as the poet wrestled with philosophers such as Plato and Descartes . 
For further information, see the following:
*http://www.iep.utm.edu/plato/
*http://plato.stanford.edu/entries/plato/
*http://classics.mit.edu/Browse/browse-Plato.html
*http://www.egs.edu/library/plato/biography/
==Plato and Stevens ==
The following are references to Plato in Stevens' poetry: 
*“Homunculus et La Belle Etoile,” line 34: That know the ultimate Plato,
*“Extracts from Addresses to the Academy of Fine Ideas,” line 51 (ii.26): Plato, the reddened flower, the erotic bird.
*“Less and Less Human, O Savage Spirit,” line 4: Or moonlight, silently, as Plato’s ghost [1] 
In his letters, Stevens explains the significance of Plato in the poem "Homunculus et La Belle Etoile": 
"About Homunculus: I had forgotten about the ultimate Plato and the torments of confusion. That, after all, is what that poem is about, and what it means is that there is a center for every state of confusion. A number of such states are described in the early verses of the poem. This seems to have been an early poem of order." [2] 
==References ==
1. http://www.wallacestevens.com/concordance/WSdb.cgi
2. Letters of Wallace Stevens, edited by Holly Stevens. University of California Press, 1966. Page 306.