The works in “Hard Truths: The Art of Thornton Dial,” at the Indianapolis Museum of Art, are tough, beautiful, disturbing, seductive, improvisatory, unignorable, fierce, exhilarating, ambiguous—and much more. They are also difficult to write about. The intense physicality and raw power of Mr. Dial’s enormous, confrontational collages and constructions, built from a staggering range of salvaged objects, resist description. Reproductions—even carefully chosen, artfully framed detailsonly hint at the fascination exerted by the dense surfaces of Mr. Dial’s most engaging creations. Words, including the string of adjectives above, seem superfluous; the best response would be to point in silence at these wonderful works.