. The Faraday’s intuitive belief in the unity of the forces of nature, or that all the forces of nature are but manifestations of a single universal force and must be convertible one into another made possible the classical electromagnetic field theory, the foundation of modern physics.
Modern physics includes the subjects of gravitation, mechanics and sound, particles and atoms, thermodynamics and heat, electricity and magnetism, light and electromagnetic radiation. Its main task is the nature, origin, actions and interactions of force-fields, gravitational, electromagnetic and nuclear, the strong color force between quarks and the weak nuclear interactions, all mediated by the quanta exchange, as vector gauge symmetry bosons.
In all, modern physics viewed as natural science doing the general analysis of nature to understand how the universe behaves, while being in the space of force fields and relying on a few simple laws and principles of nature and the universe.
Among the fundamental principles, causes and theories of the universe there are
unity and diversity,
reversibility and convertibility,
regularity and order,
symmetry and conservation,
change and motion,
relativity and space and time,
mass and energy,
fields and forces,
as well as thermodynamics, equilibrium and nonequilibrium, classic and statistical,
mechanics, classical and statistical, quantum and relativistic, field theory, nonlinear dynamic systems theory, quantum gravity, or theory of everything.
The fundamental axioms and postulates of physics are that “all is relative”, interrelated and interacted, in the physical universe, space and time, mass and motion, energy and force, but the basic principles and laws, as reversibility and convertibility, symmetry and conservation.
The symmetry concept and its symmetry operations, what led the natural philosophy of Newton and defined relativity and quantum theory, are mutually related to the conservation concept and its laws of invariances. Each conservation law (of energy or momentum or mass-energy, quantum numbers or baryon number and lepton number) has a corresponding symmetry, or invariance and uniformity (as time reversal or space inversion or parity and internal symmetries).
And all is generally specified by the algebraic concept of symmetry groups, as Lie and finite groups, going as the foundation for the fundamental theories of modern physics. The idea is to further unify the electroweak forces with quantum gravity forces transmitted by the massless quanta of gravitons.