Rav Shick [of Breslov] spent a great deal of effort and he must have printed more than several million pamphlets trying to change the paradigm [world view] of Torah from Monotheism to pantheism.
I wrote an essay on this a few years ago that brought up the basic points, but was a little too sharp {I admit.} Since Rav Shick was claiming this as if Rav Nachman had supported this, I included critiques on Breslov.
But in that essay I brought some of the relevant points: Spinoza, the Upanishads, where pantheism is held by. And I showed it has no support from the Ari''zal based on a least four of five references I brought there from beginning of the Eitz Chaim.
I did not bring up possible places of support like the Remak [Moshe of Cardavaro] or the Shelah. Some suggested also the Ibn Ezra.
I discussed this once with Israel Rozen a friend mine in Jerusalem, and he pointed out that the
Nefesh HaChaim does not actually support pantheism,-- even though some people understand it in that way.
All I wanted to say now was the clarify the basic idea of Monotheism of the Torah as understood by the Rambam and Saadia Gaon. That is that God is one and not a composite. And he made the world something from nothing. יש מאין. [ex-nihilo]. That is to say,-- that even from God's point of view nothing exists without him making it exist every second --but not that it is Him. He made everything from nothing. The world is not Divine. [Causality does not imply identity though Buddhism and Hume both conflate these issues. Buddhism has to do this because of the fact that there is no substance that continues in time. So they have to adhere to some form of causality to get identity. But I can make a tuna fish sandwich, but that does not mean that I am a tuna fish sandwich.
As Dr. Kelley Ross wrote on this issue : "Since the approach of Buddhism to the world is to break attachments, so that one does not suffer because of relationships to things, a simple way to do that is to say, in effect, that there are no things. If nothing is substantial or has any essence, this will do that job. What we get instead are the doctrines of "momentariness," "no self nature," and "relative existence." If everything exists only momentarily, then nothing is durable, and we lose that characteristic of substances. If there is no self nature, then there is nothing in things that makes them what they are, and we lose the existence of essences. If things only exist relative to other things, then (1) nothing exists independently and we lose that characteristic of substance, and (2) nothing has its own character, so we lose that characteristic of essence. So what is actually there? Well, what we see is the "form" of things, the external appearance. Since there is no self nature and things only have relative existence, what are things in themselves when we take away everything else? Well, Emptiness. This is not nothingness (a major heresy), but neither existence nor non-existence nor both nor neither. In other words, we can't say or comprehend what is there. Later, in Mahâyâna Budddhism, we get the doctrine of the Heart Sutra that "Emptiness is Form, and Form is Emptiness."
Unfortunately, Buddhism always had difficulty with the implications of all this fundamental metaphysics. The loss of substance and essence takes with it identity, so that it becomes difficult to say that an individual, like the Buddha, achieves Enlightenment and Salvation. The individual, in fact, does not survive beyond the moment, and so it is a different being who achieves Enlightenment from the one who existed previously, and a different being in turn who achieves Salvation. Buddhism attempts to substitute causality for substance, so that what I am now is simply caused by what I was before. Unfortunately, this does not restore identity. If I make a tuna sandwich, and so cause its existence, this does not mean I am the tuna sandwich. Causal connections can be within substances or pass between them, and the identity relation is contributed by the substance, not by the causality. In the end, Buddhism seems to settle into the notion of "provisional existence," which is durable and identical, and then, with some other expedients, ceases to worry about the matter. The popular belief, indeed, is that Buddhism is about finding one's true self, not about finding that there is no self at all (anatma or anatta, "No Self"). "
The Rambam thought this principle was important enough to spend the second volume of the Guide on it.