[ravi-delia]

Complex systems are net increases in entropy. The water is flowing downhill, but it takes a really weird organism-shaped path to get there. Self organization is supposedly interesting because we don't know why such a path manifests. Thus far, nothing has given the second law a second's (ha ha) pause. It's not impossible, but considering most of our foundational physics is time-symmetric it makes sense to call entropy irreversible. Even if it could be reversed (and don't hold your breath on that one), it's still the cause of the arrow of time.