T.S. Eliot's famous concept, the "dissociation of sensibility", articulated a benchmark for Modernist poetry : the new writing would seek to overcome that split between thought & feeling, reason & experience, sense & sensibility in literature, which was in part a consequence of the Enlightenment (see his essay, "The Metaphysical Poets").
Since at least the Romantic era, up to our own day, overcoming this basic division has been a project not only of the arts, but of certain sectors of science, social science, psychology & even politics. The dissociation of thought and feeling in literary style shares broad parallels with myriad polarities : theory/practice, reason/emotion, mind/body, intellect/sensation, thought/action, idea/thing, conscious/subconscious, human/animal, divine/human, male/female... and one could delineate the central motivation for numerous intellectual and socio-political agendas in the overcoming of one or another of these basic binaries.
Central strands of ancient thought, on the other hand - both Greek philosophy and Hebrew religion, for example - insisted on the substantial actuality of, and necessity for, these basic polarities. Even with a "monistic" thinker like Aristotle, for whom polarities and distinctions were perhaps more epistemological than ontological - that is, they were abstracted aspects of actual whole & unitary objects of knowledge - such differences were nevertheless necessary for an adequate comprehension of the thing itself. For Plato, for the Biblical writers, reality was grounded in a central borderline : between intellect and sense. The intellect was aligned with the invisible and eternal : mind, soul, God or gods, changelessness, eternity, universality, Ideas. Sense was aligned with all the related polarities : body, movement, animality, change, things, mortality.
Eliot's career can be seen (in simplified fashion) as following a certain trajectory : beginning with a literary allegiance to the Metaphysical poets, motivated by a literary strategy (to overcome the "dissociation" in style); and culminating in a personal conversion to Christianity, and the development of a sort of neo-medieval vision of the restoration of European culture in toto. As such, his path can be seen as a recapitulation of the historical arc of ancient thought in general. For the central polarity between intellect and sense culminated, in the ancient world, in Byzantium : in a theological elaboration (and defense) of the Christian announcement.
What that proclamation amounted to was this : there is an infinite distance between the invisible Creator and the creation he has made; there is a fundamental distinction to be drawn between divine intellect and mortal sense. Man divided himself from God by an original act of will : a turning from his intellectual source of being (God) to the things of sense (the material world). God, out of love for Man and his creation, intervened : becoming Man himself, in the Person of his Son. The Incarnation - and the person of Christ - is the matrix of union for all the polarities, the center of human time and space. In the divine-providential process, the world-historic drama enacted by the Trinity, intellect and sense, mind and body, thought and feeling, mind and heart, sense and sensibility, one and many, order and chaos, wholeness and contingency, part and whole, male and female, individual and community.... all these polarities are reunited and harmonized - as Maximus the Confessor put it - "without separation and without confusion".
We are some distance from Byzantium, today. For many, these concepts no longer have any meaningful reference in reality : they are allegorical, mythological formulae. This is understandable. Most of the words we read, the signs we apprehend, skim by in a sort of abstract streaming.... only actual experience strikes us as whole, as real. And we are rather far from the actualities, and the thought-worlds, of Palestine in the time of Emperor Augustus.
Our scepticism (or incomprehension) is also understandable from another, theological, angle, if you will. As Maximus might have put it (much more elegantly) : created things cannot, by their own capacities, comprehend that which created them. The basic division between intellect and sense - and its resolution by divine action - is essentially a mystery, illuminated for us by revelation (divine grace).
Again, I realize I am using concepts and terminology many would find terminally obsolete. My own ability to explain anything is hobbled and strictly limited. I can only (metaphorically) raise my hands, shrug my shoulders at my own incapacity. Can only say that I, along with some others, find personal, existential, experiential meaning in the scriptural record of long-ago events. I find testimonies from ancient & mythological ages which echo and ring with events from my own life, with the thoughts & feelings that arise in my own mind and heart. I find believable the radical & fantastic idea that consciousness, in its mysterious depths, rests at the foundation of the entire cosmos : we don't so much know anything, as we are known. In such manner, I guess, I have experienced, to some limited degree, the reconciliation of polarities, the overcoming of dissociations. And I continue to try to relate & express these experiences in my own fashion, in the belief that what I have experienced is not strictly private or personal or unique or inimitable, but rather is part of something real for all. As that metaphysical poet-preacher John Donne put it : "no man is an island..."