Nicholas Rescher

“The progenitor of this rival metaphysical tradition was Heraclitus. For him, reality is not a constellation of things at all, but one of processes. The fundamental ‘stuff’ of the world is not material substance but volatile flux, namely 'fire,’ and all things are versions thereof (puros tropai). Process is fundamental: the river is not an object, but a continuing flow; the sun is not a thing, but an enduring fire. Everything is a matter of process, of activity, of change (panta rhei). Not stable things but fundamental forces and the varied and fluctuating activities they manifest constitute the world. We must at all costs avoid the fallacy of materializing nature.”