Hear at least two takes on the debate surrounding the theory of female evolution during a production of “The How and the Why” in Trinity Repertory Co.’s Dowling Theater. Directed by Shana Gozansky, the play features a mentor and her protégé who bond and spar over the personal and professional consequences of their opposing theories. “The How and the Why” was written by Sarah Treem of HBO’s “Treatment,” and has been described as powerful and intimate. Peformances star Barrie Kreinik as Rachel and Anne Scurria as Zelda.