Take a look at this,'' he demands, shoving a huge, musty tome into my hands. He takes it back and opens it up. ''It's Dante's 'Inferno,' and these are the original Gustave Dore illustrations. Look at that,'' he says pointing to an etching of a bat-winged demon tormenting a soul in some lower circle of hell. He's been immersing himself in the subject: ''Aquinas and all those people discuss this, but they never arrive at a definition of evil, which I found interesting. The only thing they could come up with was that you couldn't define the principle because it was always a paradox of opposites.'