We give a heuristic argument that shows how all the correlation functions at large distances and times of a translationally invariant one-dimensional quantum liquid are determined by one (bosons or spinless fermions) or two (spin-1/2 fermions) correlation exponents. The argument is based on the observation that in the path-integral formulation of the problem the effect of creation and destruction operators can be seen on inserting dislocations in a two-dimensional crystal of particle world lines.