Speaking of the withdrawn:
"The inexorable order of the world, which is inferred from the succession of objects in perception, is conceived as the busy surface of a process that is, for the most part, inapparent or concealed. The
concealment of the ubiquitous is a validation of its centrality. The necessities of thought are habitual and invariant, and so remain in the background. The essential is inapparent precisely because it is invariant. In contrast to the multiplicity and variety of finite actualities, the change or becoming through which they develop is uniform" (89).
And on p. 86, the section on "Buddhist belief and process thought" he sounds in some ways like our OOO friends:
"The response to the real in Buddhism is a retreat from the actual to an embrace of the indefinite, since the actual becomes definite when it becomes real. For the Buddhists, antecedent potential is coordinate with ultimate reality. Suzuki writes that emptiness is a zero full of infinite possibilities. This is a potential without content, a not-nothing that is not yet a something. Emptiness is not absence."
"That a category is a mental structure does not mean it is a product of mind alone. The continuity of the categories of mind with those of nature is the metaphysical ground of autonomy...a substance, an object, a self, are all categorical objects.... An actuality never endures, concretely, it is never fully present, but perishes as it actualizes" (xii - xiv).
I like this recognition of categories as fundamental, akin to L&J. However he seems to say that the end points of the hierarchy of categorization are where the originating or defining categories reside, whereas the baser concrete is in the middle. It's almost like Platonic ideals. L&J seems the reverse in that the mid-range is where the basic categories reside because they are the most concrete, with the ends of the hiererchy being more abstract and therefore farther away from the connected root to the field of lived experience.
Also while the referenced quotes seem to show similarities to OOO's withdrawn substance, the distinction above also indicates some difference. In Bryant, for example, the withdrawn is still not an absolute, timeless or indestructible essence but rather also contingent and impermanent. Granted in Buddhism generally this is the standard line too but Brown is admittedly of the Yogacara clan so we can see where this form of Buddhism might reserve such an Absolute. I've had this argument with Bonnie more than once, also an admitted Yogacarin (at least was at one point).
From Bryant on Whitehead, one of Brown's sources, on the issue of microgenesis:*
"I believe Whitehead’s account of actual occasions is incoherent or leads to a view of being as magic. If each absolute occasion is an absolutely instantaneous novelty and atom that issues from nothing else, then actual occasions are creations ex nihilo. That’s magic."
* Defined by Brown:
"A theory of becoming is retrospective, it is the creation of the present out of the past, or the revival of the past in every actual occasion" (xii).
It is not created ex nihilo but still, each actual occasion is re-created in each moment. Bryant too is process-oriented in that an object must constantly re-create itself anew or face dissolution. But there is no underlying sky-hook or universal plenum from which to draw for this re-creation.
Interestingly, Brown asserts that change cannot happen without this moment-to-moment recreation. Yet Bryant asserts that change cannot happen with it! See chapter 3.4 of TDOO, for example:
"What we get with Whitehead is a sort of radical actualism where every change implies an entirely new entity. Yet if this is the case, it is difficult to see how we can get from one entity to another entity. Rather, it seems that entities must possess the capacity, the potentiality, to undergo change."
Bryant thinks this comes from the failure to distinguish the concrete, the actual and the virtual. We see Brown doing this but from a more Yogacara flavor, or what he calls a process monism (ix), with a similar if less idealistic universal plenum at root.