### 2.2 Kinematics vs. dynamics

A complete physical theory must obviously include dynamics. However, over the years a number of
kinematic frameworks have been developed for testing Lorentz violation that do not postulate a complete
dynamics [246, 211, 205, 20]. Furthermore, some proposals coming from quantum gravity are at a stage
where the low energy kinematics are partially understood/conjectured, but the corresponding dynamics
are not understood (a good example of this is DSR [186]). Hence until these models become
more mature, only kinematic tests of Lorentz invariance are truly applicable. Strictly enforced,
this rule would preclude any use of an experiment that relies on particle interactions, as these
interactions are determined by the dynamics of the theory. Only a select few observations, such as
interferometry, birefringence, Doppler shifts, or time of flight are by construction insensitive
to dynamics. However, the observational situation is often such that tests that use particle
interactions can be applied to theories where only the kinematics is understood. This can be done in
astrophysical threshold interactions as long as the dynamics are assumed to be not drastically different
from Lorentz invariant physics (see Section 6.4). In terrestrial experiments, one must either
recognize that different experiments can give different values with kinematic frameworks (for
an example, see the discussion of the Robertson-Mansouri-Sexl framework in Section 3.2)
or embed the kinematics in a fully dynamical model like the standard model extension (see
Section 4.1.1).