Why physicists are trying to unify gravitation with other 3 forces (weak, strong, e&m)? What if gravitation is actually not a force but a consequence of the mass's disturbance in space-time geometry? (like Einstein proposed) I don't understand their persistence on this unification. Maybe gravitation has different nature than other forces, and we can still seek for a theory of everything. Is it only the struggle of adaptation to proposed models (like standard model)? Is that the only reason?