| The arrow of time moves forward, but the arrow of evolution doesn't exist. Full stop. Evolution is the change in heritable traits over successive generations. A situation where this stops is as impossible as one which it goes backward. It may go really, really slowly, but the second law of thermodynamics means it will continue. As such, I don't think there's anything wrong with understanding evolution as a ceaselessly progressing pattern. The idea that evolution could go backwards (devolve) is flawed and confuses the idea of evolution. We can only go backwards if time goes backwards. There is no underlying "fundamental" or "less-evolved" entity that can be reached from the present state by un-doing the steps that got us to the present. To reach a past state, a species must start from the present, so it is still evolution.