Literature is awash in clever, fictionalized meetings of historical celebrities, and for some reason, they always intrigue me, whether it’s Indiana Jones meeting Hitler or Alien actually going against Predator.

OK, bad examples.

But a very fine example, which finishes its run this weekend, is Freud’s Last Session at Theatre 3. In 75 breezy but intellectually stimulating minutes, a dying Sigmund Freud (T3 founder Jac Alder, is a rare performance) invites aspiring Christian novelist C.S. Lewis (Cameron Cobb) to his London home at the height of the Blitz. Freud — born Jewish but an avowed atheist — has summoned the Oxford prof to inquire as to why any sensible man would, as Lewis did, convert from atheism to diehard Catholic in the twinkling of an eye. The last time it happened so suddenly was with St. Paul on the road to Damascus; certainly the English countryside could not compete with that?

Freud and Lewis spar, as only two men set in their ways can, poking holes in each others’ philosophies while trying to remain ever-respectful of the man in front on him. Trust me: The presidential debates have nothing on these guys.

Mark St. Germain’s lucid, whip-smart and challenging play brings up more issues that it answers; no one wins here, although Freud makes some of the stronger points in my book about how Lewis’ God could allow the Nazis to rise to power (and this was before we knew about the Holocaust). But along the way they discuss art, faith, humanity and literature in ways few plays attempt nowadays. And it’s over almost before it began.

A chief draw of the play, which has still a few more performances left, if the pas-de-deux between Alder (a gifted and convincing actor who is welcome to do more than curtain speeches whenever he wants) and Cobb (perfectly tweedy and intense). Director Terry Dobson provides them with a lovely set to meander through while giving them free rein to parry about heady ideas. Thinking never was more entertaining.

For tickets and more information, visit Theatre 3.