Heim based his unified field theory on 4 general principles:

The geometrization principle, which states that interactions can be described by a polymetric which is defined by transformations between spacetime manifolds.

The optimization principle, states that spacetime is a multidimensional manifold.

The dualization principle, states that since additional internal symmetries in nature are observed, a higher dimensional space should exist.

The quantization principle, which states that spacetime is made up of discrete elemental surfaces.