This article may be deemed as an exploration on the unification of fields as well as a discussion of the completeness in physics. This author tended to support the viewpoint of Einstein and believed that the Uncertainty Principle should be in itself incomplete, and that the representation of the state function ψ should not be complete in quantum mechanics. Following a series of discussions, including the hypothesis of a new quantum, the relativity of electromagnetic field, and the general equivalence principle, this author proposes here a new field equation called Hamilton’s tensor equation (HTE). Acting as the complete presentation of Einstein’s field equation and as an extension of Hamilton’s principle, what this new field equation (HTE) has revealed is that the “virtuality” of... space–time, rather than its curvature, is what determines the distribution and movement of matter and energy. Based on this new field equation (HTE), the author has extended the study to include the unification of fields, a model of new particle, and the phenomenon of black hole.