I have a great deal of respect for your work, Sam. You have diligently and patiently expressed much that is of value in Wittgenstein’s writings. While we do disagree on details concerning the nature of hinge propositions and a few other things, we have much in common with each other.
I have to disagree with you on the effectiveness of your argument here. And it is an argument, presented as such from the first:
I do not understand how you can assert something like this while maintaining much that is important in Wittgenstein. Intelligence is an aspect of the communal life of human beings, something people do together. And yet here you are proposing an intelligence that is not even a part of the universe in which such interactions take place; and worse, this intelligence is some sort of metaphysical being.
This is more than just a difference in interpretation. You appear to me to here be denying some of the most basic and important arguments Wittgenstein presented.
A separate point, apart from the stuff of exegesis, I also think I have shown that the actual argument you present suffers the same failures as other cosmological arguments, as listed in the OP. While you resist labelling your “fundamental intelligence” as “God” in the traditional sense, it is clear, from the fact that you posted it in this context, that it takes on at least some of the roles He does. It plays the game.
Also, the conclusion indulges in the generic special pleading mentioned; if we grant that there is a need for an explanation for the source of intelligence, why not stop at Us? Why must we move on to the “Fundamental Intelligence”? Or perhaps more clearly, why should that “Fundamental Intelligence” not simply be Us? You even appear to grant this, without giving us good reason.
While I’m here, I should also say something about the following:
I’ll invite you to consider that this is exactly what Davidson denies in the subject text of Reading Group: Davidson: Actions, Reasons, and Causes . There is a very strong case for treating the reason one believes some sentence as the cause of that belief. There is, at the least, a great deal more to be said here.
We can leave things there.