I had a similar discussion with a family member, about the existence of the Christian god, where I received that exact response. My wife was sitting right there. I responded with something along the lines of, "True, but my 'faith' in her love is already backed up by evidence, and besides, I have plenty of evidence that she exists. If there was evidence for God and evidence of His love, I would happily put faith in that too."

But I agree - it definitely caused me to pause to consider a tactful response.

I'm new here and didn't know if this has been a topic of discussion yet, but I found this story to be fascinating:

http://www.physorg.com/news158928941.html

In short, two psychologists modeled decision-making in a variation of the Prisoner's Dilemma with a "quantum" probability model. Their motivation was to reconcile results from actual studies (the participants consistently made apparently irrational choices) with what classical probability theory predicts a rational agent would choose.

Oh, and the quantum thing isn't new-age mysticism at all. It's simply a model wherein instead of a binary choice, a choice can sort of be 0 and 1 simultaneously. I don't claim to fully understand it, but it sounds awfully interesting.