Champion debater Harish Natarajan argues against IBM Debater, represented by a screen with a blue oval, in a competition at the IBM Think conference. The subject under debate was whether the government should subsidize preschools. But the real question was whether a machine called IBM Debater could out-argue a top-ranked human debater. The answer, on Monday night, was no. Harish Natarajan, the grand finalist at the 2016 World Debating Championships, swayed more among an audience of hundreds toward his point of view than the AI-powered IBM Debater did toward its.