Berkley, Idealism, and Materialism

In class last Tuesday we had an discussion on the consequences (or not) of accepting the materialistic worldview--does it or does it not imply a deterministic one?

I thought our response was the best I've heard today, so I think it would be a good idea if I attempted to reconstruct it, and then everyone's comments, corrections, and criticisms could formulate a strong and tangible theory. I apologize for the length of the blog (I try to keep them short) but this one demanded a little more detail.

Here are the backbones of our discussion, as I remember it:

Does materialism force us to concede to a totally deterministic worldview?

That causal forces of the material world are in a sense, predetermined because everything that happens in the 'external' world is caused by an efficacious predecessor. Therefore, if we acknowledge that our minds are no less part of the materialistic world than a chair or table, we must admit the predetermined nature of all human behavior as well.

Responses: 

-We can accept that internalist-externalist dualism with respect to our minds is largely false, while at the same time recognizing the difference between our 'minds,' whatever that may be, and our brain, basically, the biological content of our physical bodies.

-Moreover, whatever we may define as our 'mind,' we may assert that it is an emergent property of our consciousness, our sociality, and so on, and at the very least, we maintain that mind is distinct from brain, and the latter is what is demonstrably linked to the external world simply by virtue of existing in it.

-This distinction allows us to refute the criticism that the contents of our minds are predetermined by the causal, external world--at best we can say that the external world, like any existing object or idea or thing, influences the mind, which is hardly binding in any deterministic way.

-The mind originates from the brain, which is part of the materialistic world, yet as an emergent property in some sense creates a new dimension to it--therefore the causality of the materialistic world does not become more complex, but rather, the mind expands causality to the point at which we can either refine the term or choose another one.

For example, imagine the causal forces of the physical, materialist world to be projected on a standard line graph, with an 'X' and a 'Y' axis. The emergent property of the mind, rather than existing on the graph, as say, the biological brain does, adds a third dimension to the graph, and thus prevents determinism from charting our 'predetermined' actions, on the original graph.

Finally, I would add that this argument in no way eliminates all elements of determinism in our lives; it merely refutes the challenge that materialism necessitates holistic determinism.

I've probably made some errors or omissions along the way, so I look forward to your comments!