I'm lecturing a course on the new speculative philosophy (I nicknamed it 'History of Philosophy since 2007'). But we started out discussing some themes in Whitehead, basically prehensions and the nature of the speculative method. Last Thursday the discussion ended up being mostly around the incompatibility between a speculation strategy that takes coherence and broadness of a general scheme as a measure of success (the plane metaphor in Process and Reality) and the lack of space for any sui generis phenomenon or event (any anomaly, any element of its own kind etc). That led us to the long history of the anomaly of the mental - in a sense, the history of some version of skepticism - and the way Whitehead engages with Descates cogito seeing it as a revelation of a broader scheme rather than a discovery of a sui generis realm of things. The speculative method itself seems to prevent schemes that are insufficiently general, such as a sui generis realm of the mental.
Surely, one could take the realm of concepts as broader than the realm of nature or capable to encompass it. That is, one can be a monist of the spirit, so to speak.This, surely, is the classical form of a metaphysics of the subjectivity in Meillassoux's terms. But it is interesting to notice how Whitehead's take is the opposite view, it discards the sui generis by making the Cartesian scheme more general in nature and not by making it encompass everything. It is not that correlation runs amok but rather that correlation that teaches us a lesson (and, in a sense, a lesson about facticity) concerning the rest of the world. There is nothing special about the correlation between us and the world, it is not sui generis in any sense, but it is an example or a point of departure for the flight of the plane (Didier Debaise told me he doesn't like the word example in this context). Maybe speculation could go both ways but it in the Whiteheadian way, it leads towards absolutes, towards general schemes that are independent of *our* correlation.