The Prof might consider evolution to be the expression of a force, that is, the derivative of change. Something like an acceleration. An acceleration does not mean the speed must increase, but the direction would change. We see several positions [from the few fossils that remain] on the evolution tree and infer a speed of change, but that doesn't account for branching. Acceleration would account for branching, and evolution would be acceleration as the relation of the force to the biomass. Explain that to the jury, Prof.
Yeah, and someone who didn't understand economics could consider capitalism as a force, one that mysteriously changes corn fields into shopping centers. But that's not quite what's going on.