Septimus: When we have found all the mysteries and lost all the meaning, we will be alone, on an empty shore. Thomasina: Then we will dance. (2.7)
Yep, we're all doomed, but let's dance anyway. The play raises the question, if the universe is falling apart and we can't stop it, what should we do? Thomasina's answer (party like it's 1899!) may seem frivolous, but are there any better options?