William Blake is a poet, not a metaphysician. When someone writes with aphorism, irony, and wild and flamboyant system building (as Blake and Nietzsche did), they are mocking essentialism; they’re showing that language is infinite; that there are a gazillion ways to describe the world, and they’ve just created a new way to talk about it.
Blake is human evolution “LIVE!” and in action; the infinite imagination on the move. Blake puts on display as provocation and reminder the evolutionary superpower we have been given for redescribing things. We have, as individuals, the power to ignore what outside authorities take to be the essence of things, and to notice something else. Like Adam, we ourselves have the power to name the animals. It is human therefore to reach for the “disordered” and “abnormal”; to gamble in the direction of overgoing what is.
There’s no final language for this process, there’s only Blake (and people like Blake). There’s no pointing to a final essence with a final vocabulary, so to stop at a language like, say, Catholic Thomism is to lack sui generis individuality and imagination. It’s to stop growing.
Catholic Thomism started as a new language; a giddy incorporation of Aristotle into Christianity. What an adventure. But now it has solidified into the cranky rejection of women’s equality for the priesthood and no gay marriage. What a come down. How obviously it has veered into a ditch.
But there is only art. Blake’s Jesus is an artist, not an essentialist. Blake’s Jesus points to the moon, not to essences. The moon is always accompanied by an elipsis, like Walt Whitman’s grass. “What is the grass? The grass is x… and now it’s this, and now it’s that, and now it’s the flag of my disposition, and now it’s the uncut hair of graves, and now it’s…” There are no essences, only descriptions. If you tighten the noose of essences around Blake and Whitman, you lose Blake and Whitman (and tame poetry in general, and the danger that poetry represents to all systems, which are themselves tropes for essences).
This is why Plato didn’t want poets in his Republic. They were dangerous. They didn’t mirror the one truth that Plato thought he had grasped. They didn’t tell the TRUTH; they didn’t fit into the societal structure oriented to the TRUTH.
Poets have always reminded people that talking differently is possible; that the ontological mystery–the mystery of being itself–can’t be grasped in a final vocabulary; that when a poet points and speaks to the ontological mystery, that it must necessarily fail because the ontological mystery cannot be pinned down. (I’m using the Catholic existentialist Gabriel Marcel’s phrase, “ontological mystery,” in case you’re wondering where that phrase is from.)
In any case, this inability to pin down the ontological mystery is like human nature itself. As Sartre said, we are existence before essence. It’s the superpower evolution has given us, to be an open platform. It’s our evolutionary strategy, to not act on instinct, but to creatively re-purpose nature and culture.
All poets thus remind us of the possibilities of the open platform–and hence of the problem with essentialist metaphysics and cultural inertia. Blake and all poets are the children of evolution and revolution.
Prometheus Unbound 
I enjoy your blog. I doubt we share the same answers about everything, but appreciate that we are asking many of the same questions, which often have, seems to me, considerable existential import. We also share, I think, some of the same frustrations, especially those that might come from … let’s say, epistemic vices.
I’m no academic philosopher but would characterize one of my hobbies as the Search for a Goldilocks Epistemological, avoiding – not only epistemic hubris, but – an excessive epistemic humility.
Authentic philosophical theology, in my view, validates our questions regarding primal realities, demonstrates the reasonableness of our ultimate concerns. It halts there, constrained by ontological undecidabilities, metaphysically, and epistemic constraints, methodologically. It doesn’t pretend to have answered those questions. It might pave the way for many to – not without reason – engage an existential disjunction, a living as if, this or that may be the case regarding primal reality. Faith might thus ensue, an existential leap, going beyond the epistemic warrants of evidential-syllogistic reasoning (not without it), normatively justified, perhaps, via weaker, informal reasons, e.g reductios and pragmatics, or even evaluative posits.
Something else is going on with those who cursorily dismiss other “models” or ridicule those who pursue other disjunctive forks, existentially, as if they didn’t, necessarily, enjoy the same degrees of epistemic virtue or of existential actionability, as if they were necessarily believing and behaving irrationally. What’s going on? In manifold and multiform ways, folks are making either too little or too much of abductive, inductive and/or deductive inference.
None of this is to say that all competing models of primal realities necessarily enjoy epistemic parity, only to suggest that the best theological, atheological and nontheological models can and do. People of all walks and hermeneutics can and do enjoy life’s higher goods in abundance – truth, beauty, goodness, freedom and unity, love even. Those of us who opt to live as if one model or another best realizes these values in a superabundant manner (the most one can aspire to) have the onus on us to demonstrate same in the way we live, move and have our being.
That said, Thomism isn’t monolithic. There are expressions of same that, when coupled with modern science, drive toward many of your own conclusions. Those that don’t are often using bad science, even if with good philosophy. Over-against a vulgar essentialism, many adopt substance-process approaches. Few would rely only on natural law but would employ relationality-responsibility and personalist approaches, in a way that’s more cumulative case-like, less facilely syllogistic (fundamentalism of the rationalistic, evidentialistic sort). Those who urge, politically, for example, certain of their moral pronouncements as if they should enjoy a universally compelling normative impetus, are, for all practical purposes, naive realists, caught in a nonvirtuous cycle of abductive hypothesizing and deductive clarification without the benefit of inductive testing, as if the analytic and a priori, alone, could ever reveal what the rest of us would consider necessary and sufficient for existential actionability. They often think we’re morons.
The most charitable thing one can say about essentialism is that, made tenable, it is irrelevant. Most versions are rooted in irredeemable notions regarding causation, knowledge and representation.
No too few Thomists would agree.
http://lyfaber.blogspot.com/2013/09/pope-francis-on-thomism.html?m=1