AI, Machine Learning and whatnot

Interesting article in the latest issue of AI Matters (free access).

So it seems we’re now in the epoch of Machine Learning.

Looking at AI as the cosmology we can identify the epochs of Cybernetics (1950s-1970s), Expert Systems (1970s-1990s) and now Machine Learning (1990s->).

But wasn’t there some kind of issue with naming epochs that we’re still experiencing? (I somehow remember something like that from geology, or geochronology).