Filipino filmmaker Lav Diaz has won the Brian Award at the 83rd Venice International Film Festival for “Let Us Through, Dear Ancestors” (“Makikiraan Po”), a collateral prize given to the film that best embodies the festival’s spirit of rationalism, human rights, and pluralism. The Brian Award, known in Italian as Premio Brian, has been presented since 2006 by the Italian Union of Rationalist Atheists and Agnostics (UAAR), a secularist advocacy group affiliated with the global network Humanists International. Named for the Monty Python film “Life of Brian,” the prize goes to whichever film screened at Venice that year most strongly advances values the UAAR champions: rationality, freedom of conscience, and equal treatment regardless of sex, gender identity, sexual orientation, or religious belief. “Let Us Through, Dear Ancestors” is set in 1617, during the height of Spain’s colonization of the Philippines. Bart Guingona plays Padre Enciso, a Spanish friar overseeing the construction of a church who sends his son, Dungwen — played by Christian Bables — to move limestone through territory where native communities are still …