Of course no idea appears ex nihlio - but I think certain ideas are just so novel and groundbreaking that they mark a qualitative change in humanity (I would in

Of course no idea appears ex nihlio - but I think certain ideas are just so novel and groundbreaking that they mark a qualitative change in humanity (I would include, for example, newtonian physics, relativistic physics, or quantum mechanics.) I just feel like their were are far fewer (if any) of those truly ground breaking discoveries now than there were in the early 20th century. This might just be perspective bias, but it seems like scientific progress was being made much more quickly from, say, 1850-1950 than any other time in human history. We still have a lot of big open questions, but progress seems to have slowed down. Hopefully the LHC will change that ... As for the Grand Challenge, I work in the AI field myself (I'm engaged in some work for DARPA right now, and I know several people who were on Grand Challenge teams), and we're still basically stuck in turing/von-neumann paradigms. In my opinion, most of what we've done in the last 50 years in AI is come up with better search heuristics. It makes AI/ML much more useful - but it's nothing really paradigm shifting. I will of course grant this could all be in my head, since I haven't, and probably couldn't, define a metric that measures the 'significance' of theory (maybe something about marginal information-theoretic predictive power, but that's difficult to measure and still not quite right).