it is growing at a pace close to exponential.
I wonder how he (or anybody else) measures growth of knowledge. Are there any sensible metrics beside amount of paper created? I understand that published pages is a measure as is number of patents but I don't think these are useful proxies for knowledge.
What other measures might be used?
Complexity measures of the created knowledge: Depth of the gratph of citations between papers (assuming each citation adds something; might be weithed by the number of outgoing refs)
Complexity of the created artifacts (programs, machines). E.g. number of abstraction layers. Or other standard complexity measures thereof.
Speedup achieved by the methods when applying them to optimize tasks. (Exponential speedups in this domain could result from self-optimization and are dangerous and I really hope that those are not implied by the OP).
Ability of the research work (persons or software) to acurately describe/model real-world phenomena of a given (and exponentially growing) size. This I think is the most likely candidate.
More simple quantities: Number of researchers in a field, number of conferences, number of mails exchanged about a topic
And of course subjective complexity. I guess we are bound to label anything exponential that grows faster than we can keep track of.
Elon Musk submitted a comment to edge.org a day or so ago, on this article. It was later removed.
Now Elon has been making noises about AI safety lately in general, including for example mentioning Bostrom's Superintelligence on twitter. But this is the first time that I know of that he's come up with his own predictions of the timeframes involved, and I think his are rather quite soon compared to most.
We can compare this to MIRI's post in May this year, When Will AI Be Created, which illustrates that it seems reasonable to think of AI as being further away, but also that there is a lot of uncertainty on the issue.
Of course, "something seriously dangerous" might not refer to full blown superintelligent uFAI - there's plenty of space for disasters of magnitude in between the range of the 2010 flash crash and clippy turning the universe into paperclips to occur.
In any case, it's true that Musk has more "direct exposure" to those on the frontier of AGI research than your average person, and it's also true that he has an audience, so I think there is some interest to be found in his comments here.