TELLURIDE, Colo. — A film festival held almost 9,000 feet above sea level on a holiday weekend may not be the likeliest setting for philosophical speculation, but for the past four days the Telluride Film Festival has offered something like a seminar on the nature of truth. In an age of reality television, journalistic fakery and political mendacity everyone knows that words and images can distort and mislead. And film is a particularly unstable medium, alluring us with a promise of honesty while it feeds us ever more elaborate fantasies....

Or else we might start with movies that are obviously about real people and events and just as obviously works of entertaining make-believe. In Roger Michell’s “Hyde Park on Hudson,” for example, the role of Franklin D. Roosevelt is played by Bill Murray, who noted at a post-screening Q. and A. session Saturday that he had previously been asked only to portray presidents in comedy sketches, and that Roosevelt was a very big historical deal. “He’s on the dime,” Mr. Murray reminded the audience. “You know what a dime is, right?” he asked Mr. Michell, who is British but who nonetheless seemed to have some notion....