If I recall correctly, for Graham Harman and perhaps Object-Oriented Ontology generally, an individual cannot be exhausted by any or all of its relations. Thus there is some kind of irreducible essence that is particular to that individual object.
But there’s something circular about this idea, because it offers a definition of the individual object by reference to a notion that already implicitly assumes a definition of what it means to be an individual. To say that an object cannot be exhausted by any or all of its relations is to assume from the outset that an object is the sort of thing that can in principle be abstracted from its relations.
I think we can have a robust conception of the individual without any reference to essences while also avoiding the same kind of circular reasoning. By “robust” I mean an account of the individual in which it cannot be reduced to its relational parts nor holistically subsumed into some greater network—what Harman calls “undermining” and “overmining,” respectively.
Instead of defining the individual as what cannot be reduced to its relations, we can say that relations do not exhaust what an individual actually is or can potentially become. This liberates the individual from being delimited by or beholden to any of its particular relations, thus giving it room to change and participate in novel arrangements with others. Harman’s objects are limited in terms of the kinds of relationships they can participate in with others: because each individual has a private essence specific to it, its possible states are identical to its number of relations. Contrast this to my object, which have the capacity to transform upon encounter with others, thus cumulatively multiplying the amount of possible states with each new relation.
My kind of individual cannot be said to have a private essence particular to it since we make no reference to such an essence; we only say that no relations can exhaust the totality of what an individual is and/or could be. This also means that no individual exists outside of its relations. An individual is constituted by its relations while also being irreducible to them. This is because, strictly speaking, individuals do not ontologically exist: the extent of their spatial and temporal bounds as well as the set of characteristics that define them are all conceptually imputed by the mind upon the indeterminate manifold totality of sense-experience. So while we can analyze an individual and divide it up into its respective parts—whether these parts are considered compositionally and/or sequentially—the individual in question is neither identical nor different from its parts and relations, because there is no individual that actually exists.
To the extent that we speak of and/or refer to individual objects or processes, we speak in terms of relationships. But ultimately speaking we can neither reduce an individual to its relationships, nor can we characterize it as something over and beyond its relationships, because to do so would be to presuppose that such an individual exists in itself, objectively and independently of the mind which takes into consideration. But since objects are always-already objects of a particular concern, no such independent individuals actually exist.
We cannot undermine nor overmine an object, not because it occupies a private existence beyond its parts and relations, but because it does not, strictly speaking, ultimately exist.