Proof centers on Catherine, who gave up a promising career in mathematics to care for her father, a brilliant mathematician, as he slipped into mental illness. Now that her father has died, Catherine's sister and new beau find themselves grappling with the question of how much of her father's brillianceand madnessCatherine has inherited. What makes Proof work so well is that it makes Catherine the heroine while convincing the audience that the doubts about her may be justified. It also gives equal time to the complex relationships between all four of its characters, persuasively showing the love that binds them together and the power struggles that drive them apart.
Director Kate Galvin's lovely production draws you in immediately; both Andrew Thompson's back porch set and Lauren Perigard's varied costumes look believably weathered. And Galvin's cast is terrific, especially Alex Keiper, who gives Catherine a dash of the kooky, sexy charm that Mary-Louise Parker had in the Broadway production. Keiper plays Catherine with a twinkle in her eye, but even in her most relaxed moments, it's clear that the wheels in her mind never stop spinning. Keiper conveys all the sweetness, sarcasm and tenacity that make Catherine both likable and frustrating to the people around her. Krista Apple is sharp as the sister who is condescending to Catherine at first but later lets us see behind her fašade. Bill Van Horn is sturdy and gentle as the father who still looms large in his daughter's mind, and David Raphaely plays the new man in Catherine's life with a mixture of tenderness and trepidation.
The Walnut's Proof is a beautifully crafted drama with naturalistic dialogue and solid chemistry between its four actors. It's worth catching.
Proof runs through February 5, 2012, at the Walnut Street Theatre Independence Studio on 3, 825 Walnut Street, Philadelphia. Tickets are $30, and are available by calling the box office at 215-574-3550, or online at www.walnutstreettheatre.org or www.ticketmaster.com.