Peeking in on A Conversation About the Holy Spirit

I’m a bit choosy about the faith-based topics that I post here. Not because they are too deep, or that I don’t want some measure of transparency. I would rather the topics that I post here endear just as much thought, and sometimes more discussion than other topics. To that end, I’m sharing a piece from a email conversation that I have with one friend by email and f2f (a few others included on the email) about the Holy Spirit. The question was a toughie: how would you describe the Holy Spirit to a non-(Christian) believer?