An Objection To Cartesian Dualism

There's a distinct possibility that absolutely no one who reads this cares in the least about this. So skip this one, I'll have a book review up in a day or so (for the 1988 Novel Wittgenstein's Mistress). Maybe less, maybe slightly more. This one will then be for a random person who happens upon my blog, or on the off chance that one of you have any interest.

All right, this probably applies to more than just the dualism in Descartes. In general it applies to any metaphysical dualism (matter + minds) where we also imagine God created these things. And I know Descartes thought this was the case. So on to the spirit of my objection:

We have these ideas: Matter is material, extended objects, not thinking things. The thinking things are minds, not-material, not-extended in space. The interaction, as I understand it, is that perceptions, pains, thought, emotions, and all that takes place in the mind. It takes place in the non-material part, even if caused by the material part. So here's the problem: Material is superfluous. It's unnecessary, and I can't see any reason for a perfect being to create it.

All of the effects of material objects could be founded completely within minds. As a matter of fact, to the minds it would be all the same. So why create material things at all? What reason would we have to believe they exist, and that minds also exist. Especially if matter is equally capable of doing the work of minds (a trivial point) in which case you have two things that can each do both jobs. However, the way minds are described, at least it seems that that should be all that is necessary. So why both?

I've read it over, and it looks as if Descartes tries to explain his dualism in the Meditations on First Philosophy, in a way which might respond to this, however for several reasons I don't buy his argument. For some of his answers, it's the same I don't generally buy the case of dualism, but here's what is the crux of his argument, from what I can tell: God is not a deceiver. This doesn't respond to anything, as I do not believe (say) an idealist picture (mind, no matter) would claim God IS a deceiver. For after all, our perceptions tell us nothing but what he establishes earlier (med 2) that we perceive x or y quality. Berkely's right here: it's qualities, not objects which we perceive.

An argument from simplicity seems to rule dualism out one way or another, is how it looks to me. Back to Occam's Razor: Entities must not be multiplied beyond necessity, or in other words "all other things being equal, the simplest picture is the most reasonable to believe." The reasonable model here doesn't seem likely to be dualism, or not the cartesian case as I've seen it. Spinoza makes sense here, multiple aspects to the same thing.

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I'd love to hear (and respond to) any arguments. I rarely hear this argument against dualism. I'm not sure if it has any history, or if any philosopher has made it, so sources on this would be interesting.