In defense of the black box

The science fiction writer Douglas Adams imagined the greatest computer ever built, Deep Thought, programmed to answer the deepest question ever asked: the Great Question of Life, the Universe, and Everything. After 7.5 million years of processing, Deep Thought revealed its answer: Forty-two (1). As artificial intelligence (AI) systems enter every sector of human endeavor--including science, engineering, and health--humanity is confronted by the same conundrum that Adams encapsulated so succinctly: What good is knowing the answer when it is unclear why it is the answer? What good is a black box? In an informal survey of my colleagues in the physical sciences and engineering, the top reason for not using AI methods such as deep learning, voiced by a substantial majority, was that they did not know how to interpret the results.