A towering intellectual and literary figure and contemporary of G.B. Shaw and H.G. Wells, G.K. Chesterton may find his most avid fans these days among the horde of slightly younger, growingly inveterate mystery readers, who’ve finally discovered his Father Brown whodunits and will devour them on their way to the oeuvre of yet another vintage crime writer — like, say, Dorothy L. Sayers. But Chesterton (1874-1936) was way more than a mere popular novelist — he was a vital social and political thinker, an eggheaded Catholic with serious, hard-won cred, and an important Christian biographer. And a dramatist — which the producers at the thoughtful Blackbird Theater have affirmed with their new mounting of this fairly forgotten play, concerning an aristocratic family whose conflicting beliefs and doubts about the supernatural are all challenged by the arrival of a mysterious conjurer. Magic aspires to be humorous and unabashedly romantic, while also offering what director Wes Driver calls “passionate debate about big ideas.” The cast is led by David Compton and Amanda Card McCoy — both of whom were in the acclaimed Blackbird production of Tom Stoppard’s Arcadia — plus Alan Lee, Robyn Berg, Daniel Hackman, Zack McCann and Chris Bosen.