They evaluate all moves from the current position, to a certain depth, then start pruning. It's obvious they cannot evaluate all moves till the end of the game - that would mean chess would be "solved", and it isn't. It will technically unfeasible to solve chess the brute force way for many eons to come. But before pruning, even at the earliest level, a chess program must consider all moves from the current position - after all, pruning is done based on evaluating positions.

Okay, we don't "know" how humans make this pre-selection; does it matter? does the mechanism with which the selection is made determine whether it is the exhibition of intelligence? Or is the ability to make the selection and decision the exhibition of intelligence?

The ability to make selections and decisions doesn't make intelligence. After all, any program with an if makes a decision.
(But I don't want to go into the question of "what is intelligence"? That's a holy way I don't feel stepping into.)

If it is the mechanism which is the difference and we don't know what that mechanism is, then how can you state that the mechanism used in AI is shallow or unsatisfactory for the problem set?

I never said that the mechanism used in AI is shallow. What I said was that if you call the rather brute force technique of chess programs (despite some pruning, the technique is brute force, as it considers way more paths than are needed for the "solution") AI, then the term AI becomes shallow. Brute force techniques are amongs the simplest techniques of solving problems.

Abigail