At Quintessence Theatre, "Major Barbara" (1905) by George Bernard Shaw gives us a boxing match showdown between a soul-saving Christian and a triumphant manufacturer of gunpowder and munitions. Barbara Major is one of Shaw's debate-discussion plays in which he claims the salvation of mankind is at stake.

Andrew Undershaft abandoned his family long ago to run a weapons factory. At the bidding of his estranged wife, Lady Britomart (what a name), Undershaft returns to the family drawing room because the grown children need his money.

Undershaft sizes up his daughter Barbara as a kindred spirit. When Undershaft learns she helms a Salvation Army soup kitchen he offers Barbara a deal: Undershaft will visit her soul-saving operation if Barbara will visit his arms factory. Their standoff is the guts of the play, but minor characters give Major Barbara sorely needed tang.

As the scene shifts, the actors who play family members also play down-and-out characters at the soup kitchen.

Gabriel W. Elmore plays Charles Lomax, Sarah Undershaft's suitor, and Snobby Price, a soup kitchen denizen. Both are happy in a dumb, giddy way; both are covertly predatory; neither shows any starch when confronted.

Likewise, Aneesa Neibauer plays Sarah Undershaft and Jenny Hill; both are innocuous and accepting. Marcia Saunders is Lady Britomart and Rummy Mitchens; both are women constrained by limited choices.

Only Lee Thomas Cortopassi's characters stand apart; Stephen Undershaft is passive, while cockney bully Bill Walker acts out. Yet they, too, share in a prideful self-absorption.

The Quintessence production is a scene-stealer event, and you sometimes strain to take in stellar moments at different ends of Director Alexander Burns' central, runway stage. While minor characters give the play life – someone has to entertain us – the multi-role setup also suggests the human personality is wholly self-sustaining and cuts across class lines, a bit at odds with Shaw's Fabian viewpoint.

Andrew Undershaft keeps his end of the bargain; he watches the soup kitchen show just like us. But he steps in when he learns the Salvation Army needs money to keep the operation afloat. Major Barbara disdains his offer on moral principle but is overruled by the superintendent, who argues that the soup kitchen has to accept money from any source to do its good work. The boxing match between realism and idealism ends in a knockout.

As Major Barbara, Melody Ladd has a striking presence. Standing erect with an inner glow she exults in saving souls. She daunts bully Bill; you do not doubt she would reel in his soul, too, if Papa Undershaft had not intervened. She is equally impressive in "defeat", crestfallen but still erect as Bill sneers, "What price salvation now".

The final act that takes place at the munitions factory is anti-climatic; it boils down to a non-stop lecture from Andrew Undershaft. He tells us he is the government, that he will sell arms to anyone on principle, that money and power are all that matter and he proved that at the soup kitchen.

As Andrew, Paul Parente is forceful in delivering his message with monotone triumphalism; nothing personable shines through his polemics. How does he win over his daughter so easily? With the indisputable strength of his argument?

You understand part of Shaw's proposition. Soul-saving religious idealism that distances itself from practical society is narcissistic, feeding off poverty and suffering. The same can be said of effete intellectuals who stay disengaged, like Barbara's beau, Adolphus Cusins, (J. Hernandez does not seem to know who his character is, but neither does Shaw.)

While Shaw wrote witty, original and provocative social dramas – Pygmalion and many others – he also had a cantankerous, eristic side. In his discussion plays he dons the mantel of activist theater, from Ibsen to Brecht, in arguing that the purpose of theater is to make people think. Bloviating talk show hosts and barroom bums make you think, too.

It is a stiff challenge for an actor to play a character who is more idea than person. Andrew Undershaft, Adolphus Cusins and Major Barbara are "idea" characters. At Quintessence, Barbara is endearing but Andrew is just an idea. The grand finale is farcical because you do not feel any personal basis for Barbara's conversion experience.

Yet I felt grateful for Paul Parente's impersonal approach because it lays bare a truth: Shaw's formal political arguments are mostly gibberish.

Quintessence Theatre is located at 7137 Germantown Ave. Major Barbara will run through October 29. Tickets available at 215-987-4450, or online at quintessencetheatre.org