"One prominent physician of his day claimed Berkeley was
insane. The great Dr. Samuel Johnson dismissed Berkeley's ideas with
his famous "I refute Berkeley thus" and then he kicked a rock. Of course, this did not refute Berkeley at all. It only proved Johnson had not understood Berkeley's point. Berkeley did not claim the non-existence of stones or that kicking a stone will not produce sensation. He claimed the rock did not exist apart from the perception of its solidity or the perception of pain when struck, and so on. An oft-repeated epitaph summarizes the general reaction to Berkeley: "His arguments produce no conviction, though they cannot be refuted."
You will bear in mind that Johnson's rejection of Berkeley's ideas was given in the light of the state of knowledge at the time. You will also note that we are talking about Britain in the 18th century, when the questioning of God's existence was not at all common and likely to get you into trouble.
Berkeley was just as much fooled by the lack of logic of immaterialism as the Buddhists had been 2,000 years before.
The problem is that Berkeley's ideas do not prove, or even suggest there is a god of any sort. For Berkeley's ideas to be true, you first have to assume there is a god capable and willing to imagine the universe and all that is in it down to the subatomic level.
- First assume there is a god and then you can prove there is a god if what I say without any proof whatsoever is entirely true.
If you assume the existence of gods, then, and only then, can Berkeley's Buddhist ideas work.
This then produces difficulties with Free Will
: whose thoughts would have precedent? God's or yours?
However, by Berkeley's own reasoning, god only exists if we think about him - gods are in our minds only. I think that is what atheists have been saying for some time.