I had something of an OOO weekend -- reading The Quadruple Object, reading three chapters from The Speculative Turn, and waking up at 4 am on Saturday and going downstairs to write out about four pages of notes on the interrelations between, and mutual challenges posed by, OOO, Integral, quantum, and SpinbitZ-ian perspectives. I may turn those notes into a post or blog at some point.
As you have noted also, there's some interesting overlap between Harman's or Bryant's accounts of objects/substances and Wilber's 4Q holons. Endo- and exo-relations correspond roughly with the interiors and exteriors of any holon or actual occasion. Harman, in one of his pieces, talks about the interiors of objects and goes so far as to say that the only reality is the interiors of objects. I'm not quite sure I follow what he's saying, though. On the surface, it appears he's either denying the reality of, or interpretively reducing the other 'quadrants' to, the notion of 'interior.' But this may not be the case, as I'll explain in a moment. And while Bryant allows for both endo- and exo-relations, he seems to disagree that they all necessarily 'come together' (tetra-enact) -- holding instead that it is possible for an object to be wholly withdrawn, without any relations at all. Which, from an Integral perspective, would be a privileging or an absolutizing of the upper quadrants.
Harman's view may differ from Bryant's to some degree, in that he says the withdrawn substance is not the 'bottom' of reality (which Bryant's wholly unrelated dark object would appear to be, in representing the ultimate 'end' or 'extreme' of his view on withdrawal). Harman says that even a withdrawn substance emerges from deeper relations, acknowledging that substances are both situated in and withdrawn from relations that go all the way up and all the way down. He acknowledges that any substance or object is composed of smaller objects, and often part of larger objects (similar to a holonic view), and that the smaller objects are themselves composed of even smaller objects, infinitely. He acknowledges that the infinite regress is often seen as problematic, philosophically, but says he prefers it to the other options (that reality rests on some ultimate turtle, or that reality rests on a turtle shell without a turtle). So we have a view where relations are objects, and objects are relations, and (as I understand it) all objects are simultaneously withdrawn from both endo- and exo-relations. In my mind, this is a philosophy of emergence -- related to point one of the four characteristics of living systems that I posted earlier: where living systems are nonsummative wholes. If an object or substance is emergent (the flipside of withdrawn?), it eludes its constituent parts or sub-holons (not being reducible to them) as much as it eludes any totalizing apprehension by other, environing or surrounding objects.
But Harman's view may be more radical than a living systems view, it seems, because he rejects Leibniz's distinction between monads and aggregates (and likely the Integral distinction between holons and artifacts). He wants to say that two diamonds glued together are also 'objects' or 'substances,' as is a group of men holding hands, a cavalry regiment, or the Black Forest as a whole. Bryant takes a similar view, accepting a baseball team or the United States as substances. Most of these 'objects' could still be viewed in systems terms, so it's not clear how far from a living systems view he wants to venture. Are two diamonds glued together a system? Perhaps an artifactual system but not a living system. I wonder whether he would also accept contiguously situated or interacting objects as a substance -- diamonds in a bag, an ant exploring a toaster, a Republican in golf pants holding a martini, a man on a toilet? What does it take to be an 'object'?
Here's a definition he offers (which, again, appears roughly consonant with holonic theory): "Objects need not be natural, simple, or indestructible. Instead, objects will be defined only by their autonomous reality. They must be autonomous in two separate directions: emerging as something over and above their pieces, while also partly withholding themselves from relations with other entities." And elsewhere he says, "And given that an object must inherently be a unity, its multitude of qualities can only arise from the plurality of its pieces. Thus there is no object without pieces..." (The qualification of the necessary unity of objects suggesting, again, parallels with holonic theory).
Regarding Bryant's claim that an object can be severed from its relationships to other objects, what do you make of this? Does he mean all objects, or just some? Does this include constituent objects? Can a hammer be severed from its relationship to atoms, or to iron, or to wood? Or is he only talking about its relationships to surrounding objects, like the hammer's owner, or a tool box, or a set of tools, or the planet earth?
As to your questions in the last paragraph, Bryant seems to distinguish an object from its parts, in that the parts of an object, organized as its endo-relations, are not objects in themselves. He calls them "elements." I'm not exactly clear on this though, since at other times he notes that 'larger' objects can indeed be composed on 'smaller' objects, so I'm not clear at what point smaller objects become merely elements instead of objects. My guess is that the iron or wood of the hammer would be its elements so this would be distinguished from other objects like the wielder or the tool box. Not sure though.
As he says in chapter 4.1:
"In arguing that the elements that compose autopoietic systems are not ontically pre-given, it is argued that these elements are not themselves substances, but rather only exist for the endo-consistency of the substance or multiplicity that constitutes them."
I'll have to re-read some of this to get a better handle on it. A bit further on he says:
"Here we must carefully distinguish between substances and elements. Elements are always elements for a substance. They only exist as elements within the endo-structure or endo-composition of a system and do not, as we have seen, have any independent ontological existence of their own. Substances, by contrast, always enjoy an autonomous ontological existence in their own right, and therefore only exist in relations that are external to them. That is, substances are capable of breaking with their relations and entering into new relations, or of existing completely without relations at all."
I think he's following Harman in his discussion of elements, since I was just reading Harman's discussion of elements in Guerrilla Metaphysics and elsewhere. I wasn't paying that much attention to that section of the book, though, so I'll have to go back to it! About substances existing without any relations at all, I simply don't buy it. Both Bryant and Harman make such comments, but I just don't know what they could possibly mean. Perhaps the existence of such objects is a logical implication of certain of their metaphysical commitments, but since I don't see any such objects in evidence anywhere, I'm inclined at this point to think that something is wrong with their metaphysics. Or else they mean something by that that I just don't get yet.
I don't think I get it either, except in the following way. Let's use your example of a hammer. Obviously a hammer is composed of atoms, iron, wood etc. So in that sense it is in endo-relations with those 'elements.' But a hammer, once constructed as object, may lie dormant in a toolbox, never interacting with a nail. So in that sense it might remain withdrawn, never 'actualizing' its function by interacting with other objects in exo-relations. Granted this requires the fancy footwork of defining the differences between objects/substances and elements, as well as endo- and exo-relations. But if we grant the definitions then it does seem consistent. As to whether it is entirely coherent is up for debate.