One last point, because I think there’s a distinction you’re missing that matters.
You say the excess in every act of understanding points to more substance — more modes, more to explore, an inexhaustible field. But that’s quantitative inexhaustibility. “There’s always more stuff to understand.” And sure, an infinite substance gives you that. But that’s not what I’m pointing to.
Judgment isn’t just an endless procession of intelligible contents; it asks whether the conditions for affirming something have been fulfilled. And if you follow that structure through to the end, the question arises: can the totality of conditioned answers, however infinite, itself count as the unconditioned? I don’t think so. An infinite whole of conditioned being is still a conditioned order, not the ground of conditionedness as such.
So Spinoza can avoid transcendence, but only by treating the whole as sufficient for judgment. And that move stops one step too soon because the structure of judgment isn’t satisfied by any accumulation of conditioned answers, however vast. You could understand every mode of substance and still the question “is this understanding adequate?” would have to be asked about the totality itself. The excess, then, isn’t just one more content. It’s the orientation of the act itself that pushes beyond any conditioned content it could grasp, including an infinity of such contents.
And with regard to conatus: I don’t think it can do the work you’re asking of it here. Conatus is a striving to persist in being. Its not normatively structured toward truth. A false belief that helps me survive has more conatus than a true belief that doesn’t. You can’t extract the difference between adequate and inadequate understanding from a drive to persist — we covered this exact point earlier when we discussed the genesis of normativity. The normativity of knowing isn’t reducible to any dynamism within the field, even an infinite one. Its the condition under which the field shows up as intelligible in the first place.
But I think your closing thought is right and well put. We’ve arrived at the point where the commitments diverge and neither of us is going to budge. For what its worth this has been one of the better exchanges I’ve had on this forum. I think the fork you formulated is real and worth continuing to think about, even if neither of us crosses to the other side today.