I am not a conspiracy theorist at all but this Alpha Zero thing needs to be questioned for various reasons and I will serve for some limited time as devil's advocate to warm up the discussion.
#1. We are offered games without depths and scores.
#2. I don't believe it's possible 4 hours of self play can do that, not even 4000 hours, it's insane.
#3. I haven't seen an official statement from Google.
#4. Games can be played by a correspondence player with the help of Houdini tactical (or so) and cherry-picked the best ones, ignoring all the lost games also making use of massive take-backs.
CONSEQUENCES
If this type of learning is possible then (IMO) mankind is in deep trouble, imagine what in theory would be possible. Examples.
#1. Predict the stock market and get rich.
#2. Suppose politicians ask the question:
Dear comp, how do we solve global warming?
Alpha 666
Reduce the population from 7 billion to 500 million and the Earth will restore itself.
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Shoot !