The Essence of Field — A Theory of Instant Action at a Distance Based on the Three Fundamental Forces

The universe consists of a single, continuous and complete three-dimensional space, with no parallel universes, higher-dimensional spaces or fragmented spatial structures. Physically, a field refers to the spatial range where fundamental forces act instantaneously across a distance. Once matter possesses mass or electric charge, the corresponding force field forms throughout the space instantly, delivering action across a distance without propagating particles, propagation speed or time delay. An object can only be affected when it enters a field and carries matching physical properties: objects with mass are subject to gravitational force, while charged objects are affected by electric force. Objects lacking relevant properties will experience no interaction even within the field. Field strength decreases continuously following the inverse-square law, without abrupt boundaries. The greater the mass or electric charge of a substance, the stronger the field strength at remote locations and the wider the observable effective range. There are exactly three fundamental forces in nature: universal gravitation, electromagnetic force and strong nuclear force. Electromagnetic force includes electrostatic action and magnetic action, which share the same origin and belong to one fundamental force. To ensure theoretical rigor and consistent rules, this research on field theory only discusses Coulomb electrostatic force that strictly obeys the inverse-square law of distance, and excludes magnetic fields for the time being. Both universal gravitation and Coulomb electrostatic force follow the inverse-square law of distance. The strong nuclear force is built on the inverse-square relation with an additional factor for rapid short-range attenuation, and it only functions within the scale of atomic nuclei. Various fields proposed in mainstream modern physics, such as the Higgs field, quark field, gluon field, weak force field and quantum gauge fields, fail to meet the core characteristics of a field: instantaneity, action across a distance and spatial range of force. The model of force transmission via intermediate particles contains fundamental logical flaws. These concepts are artificially constructed supplementary assumptions piled up layer by layer, rather than primitive fields existing in nature. This paper redefines the underlying relationships among space, force and field, abandons redundant artificially-defined field models, and establishes a concise, self-consistent and experimentally verifiable theoretical system for primitive fields.