A common theme of much 20th century continental philosophy was criticism of presumed identities of people and things. Writers like Theodor Adorno and Michel Foucault, to name but two, systematically questioned the role of identity in our understanding of the world. Edmund Husserl had recommended suspending judgments of existence in favor of the concrete description of essences; starting especially from a historiographical point of view, Foucault recommended suspension of judgments of pre-existing unity in favor of a concrete description of differences.
Later neoplatonism like that of Proclus (412-485 CE) is commonly associated with an extreme “realist” multiplication of metaphysical entities that implicitly had their own presupposed identities. The positive side of this is a rich view of differentiation metaphysically underpinning the diversity of concrete being. But the neoplatonic technical term hypostasis is the etymological source of our verb “to hypostasize”, which basically means to attempt to artificially impose more unity on something than it really has.
But especially if we go back to Plotinus (204/5 – 270 CE), and also in later authors, there is a strong strand of what might be called “negative henology” in neoplatonism. Plotinus was the main originator of so-called negative theology in the West. Negative theology indirectly gives meaning to the notion of transcendence by pointing out how every definite description falls short of adequately characterizing God. Hen is Greek for “one”, so by analogy with negative theology, a negative henology would be an account of how everything falls short of the pure unity of the One — in other words, how things that we think of as pre-existing unities are less unified than we suppose.
Hand in hand with this perspective comes the recognition that unity has many degrees. There are a few strong unities and many weak ones, and many degrees in between. As Plotinus recognized, nothing real has the pure unity of the One. (See also Power of the One?; Plotinus Against the Gnostics; Subjectivity in Plotinus.)