One would not directly. Given measures of intelligence of evaluable existing life, work backwards to find last common ancestors given evolutionary theory from t

One would not directly. Given measures of intelligence of evaluable existing life, work backwards to find last common ancestors given evolutionary theory from the available fossil record. This leaves a lot to be desired, in my mind. Examples: * Soft tissue organisms may not be well enough preserved to be studied. * Can't evaluate intelligence in evolutionary dead-ends that no longer exist. * Limited evolution theory may miss mechanisms of how intelligence comes about, like maybe from something akin to a shared toxoplasmosis infection among different species rather than each getting there through a random walk.