Many waited with bated breath as two of some of the greatest tech minds of the generation, Elon Musk and Jack Ma, came together at the World Artificial Intelligence Conference in Shanghai on Wednesday. As expected, the energy was high and the discussion, at times, tense. In an hourlong conversation, the men behind Tesla and Alibaba had a war of words over artificial intelligence, Mars, and the future. After Ma said he wasn't scared of the future of AI, Musk laughed and said those would be the Chinese businessman's "famous last words." "I think AI is going to open a new chapter of this society of the world that people try to understand ourselves better rather than the outside world," Ma said. He added: "I'm quite optimistic.