It's very true that it's hard to predict. Whether most researchers think it "might happen in this century" can only be answered with a comprehensive survey. So

It's very true that it's hard to predict. Whether most researchers think it "might happen in this century" can only be answered with a comprehensive survey. Some attempts and analyses of such surveys: http://aiimpacts.org/ai-timeline-surveys/ http://aiimpacts.org/ai-timeline-surveys/ and http://www.nickbostrom.com/papers/survey.pdf http://www.nickbostrom.com/papers/survey.pdf It's speculation, really. The point is, breakthroughs or showstopping difficulties are hard to predict.