Alternatives to general relativity are physical theories that attempt to describe the phenomenon of gravitation in competition with Einstein's theory of general relativity. There have been many different attempts at constructing an ideal theory of gravity. These attempts can be split into four broad categories based on their scope:
- Classical theories of gravity, which do not involve quantum mechanics or force unification.
- Theories using the principles of quantum mechanics resulting in quantized gravity.
- Theories which attempt to explain gravity and other forces at the same time; these are known as classical unified field theories.
- Theories which attempt to both put gravity in quantum mechanical terms and unify forces; these are called theories of everything.
None of these alternatives to general relativity have gained wide acceptance.
