[YeGoblynQueenne]

>> Why do you dismiss the unconscious search that humans do in Go?

The question is why you say that humans perform an unconscious search when they play Go. And what kind of search is it, other than unconscious? Could you describe it, e.g. in algorithmic notation? I mean, I'm sure you couldn't because if you could then the problem of teaching a computer to play Go as well as a human would have been solved years and years ago. But, if you can't describe what you're doing, then how do you know it's a "search"?

Note that in AI, when we talk of "search" (edit: at least, in the context of game-playing) we mean something very specific: an algorithm that examines the nodes of a tree and applies some criterion to label each examined node as a target node or not a target node. Humans are absolutely awful at executing such an algorithm with our minds for any but the most trivial of trees, at least compared to computers.

[acidbaseextract]

Here's a section of Michael Redmond's (9-dan professional Go player) commentary on the Lee Sedol vs AlphaGo matches: https://youtu.be/yCALyQRN3hw?t=3031

It's really fun to watch his commentary because he relentlessly plays "variations" — possible next moves and sequences — while waiting for the players, explaining the tradeoffs between moves and the consequences they lead to a few steps ahead in the game.

I don't know what to call "variations" but a tree search with heuristics. He does it slowly to explain it to the audience, but I have no doubt the same process runs much faster in his mind.

[YeGoblynQueenne]

Fast enough to evaluate a few million future positions in a few seconds? Like I say in another comment, even professional players cannot "look ahead" more than a few ply, so whatever it is they're doing "in their heads", the tree search they're reporting is not how they win games.

To clarify, you can come up with an explanation of anything that you do, or observe yourself or another person do. For example, you might explain how you hit a ball with racket in tennis or with a bat in baseball, etc, but that doesn't mean that the process you are describing is the process that your mind (let alone your brain) actually follows.

If nothing else because such a description will necessarily fudge important steps. For example, if I describe myself walking as "I put one foot in front of the other" - have I explained enough about walking that it can now be reproduced mechanically? Experience teaches that -no.