We present a novel ontological formulation of quantum field theory, where fields, particles, and even spacetime itself emerge from a fundamental tension of ontological difference, denoted as ∇U. This field is not defined within space and time—it generates them by separating mutually exclusive possibilities: to be (+A) and not to be (–A₀). The act of separation occurs through what we call the impulse moment, a trans-spatiotemporal event that creates the conditions for stable form. We develop a quantum field theory based on ∇U and extend it into a string-theoretic ontology where strings are seams in this field—boundaries between impulse moments. Experimental and philosophical implications are discussed.