The Greeks called it "the Problem of the One and the Many." It was and remains the central problem of Western philosophy, and other philosophical traditions.
We live in a world of a myriad particulars -- ephemeral, mutable, apparently chaotic. Every tree, every blade of grass, every person is unique, and changing from moment to moment. Yet we intuitively recognize something called treeness, grassness, personness. Something deep and profound within us seeks that which is one and enduring -- the constant behind the flux.
The One might be material, as the primordial water of Thales , or the eternal atoms of Democritus. It might be the immaterial mathematical abstractions of the Pythagoreans, the Demiurge of Plato, or the omnipotent, omnipresent personal God of the Christians. In every case, the quest is for the unitary, the fixed, the generality behind the particulars.
Science is the quintessential Western way to seek the One, and is rapidly emerging as a panhuman path. What is sought is called the Laws of Nature -- the minimum number of mathematically expressible relationships that account in principle for the greatest number of particularities. In this quest, science has borrowed from Thales, Democritus, Pythagorus, Plato and countless others who blazed the trail. And for many of us, the quest subsumed the gods and supernatural spirits generally, or at least rendered them superfluous.
Science plies its trade in the realm of the general -- treeness, grassness, personness. Poetry lives in the realm of particulars -- this tree, this blade of grass, this person. Reliable knowledge of the general enhances our experience of the particular. An esthetically experienced particular intimates the general.
Each of us lives out our life somewhere between the One and the Many. As the wisest teachers have always suggested, the art of living consists of finding a balance between that which flows and that which abides.