The philosophy of Schopenhauer is an important part of the play, and not only because the character Julia has made a study of his work. The play demonstrates various concepts of Schopenhauer's philosophy - most prominently in the beginning of the play when Buddy quotes at Julia (to her surprise and admiration) one of Schopenhauer's better-known insights: "we want what we will, but we don't will what we want."
Schopenhauer's concept of "the Will" is a metaphysical, almost cosmic extra-human force. I've never been quite sure how much of what Schopenhauer says about the Will is metaphorical and how much is meant to be taken literally.
In any case, at the end of the play we see Julia, who believes she should want to be a solitary philosopher, acknowledge that what she really wants is a relationship with Buddy. She is not able to control what she really desires - she wants what she wants. This was Schopenhauer's argument against free will.
Another basic concept of Schopenhauer's work is that art is a way to find relief, at least temporarily from desires generated by the Will.
So I thought it would be fun if, in the middle of a work of art (i.e. my play) I put in some of Schopenhauer's thoughts about art v. Will.
The set-up is that Buddy has offered to listen to the lecture on Schopenhauer that Julia has been having so much trouble with, as a way to help her prepare. He thinks she might be suffering from stage fright.
Julia's lecture goes like this:
Thank you. Schopenhauer said we are all slaves to the Will. Capitol “W” Will. We are never at peace from the constant striving of the Will, except when we contemplate art. Through art we become the pure subject of will-less knowing. Many artists have found this inspirational. Richard Wagner, for example -So the easter egg here is that ideally, if the play is working right, the audience listening to these lines is made up of "pure subject(s) of will-less knowing" because they are contemplating art. Unless they are aware of the point of this passage, in which case they might suddenly snap out of the world of the play. But I doubt anybody besides me appreciated the easter egg, except possibly the Schopenhauer fanatic who showed up for the fourth performance.
I did explain to the actors during rehearsals what was going on, but I don't think they found it very interesting or relevant. And to be fair, from their perspective it wasn't relevant, since their job was to present the characters I wrote as flesh-and-blood human beings, and the author floating this little philosophical meta-layer over the text was not at all useful to them.
But I find it amusing.