Alex @ Alexander Pruss’s Blog urges that even non-social trinitarians can make a priori arguments for their trinitarian theology based on the concept of perfection.
I don’t think these sorts of arguments work, as I explain in a comment there, but check it out – Alex is always worth a read, and maybe I’m all wet.
Related posts:

Reply to Hasker re: My Divine Deception Arguments

podcast 158 - Listener Questions 3

"Trinity" @ the Stanford Encyclopedia of Philosophy

Steve Hays vs. Lexicons, deep thoughts on OT "binitarianism"

podcast 349 - Craig-Tuggy dialogue on trinitarian vs. unitarian theologies

podcast 344 – Craig’s Contradictory Christ – Part 2

Defeated?

Dialogue with the Maverick Philosopher: God is a being, not Being itself – part 5

Kimel’s review of What is the Trinity – Part 4

