Full Idea
Process philosophy can be phenomenological (as experience and order of cognition), or biological (as fundamental to life and organic existence), or as fundamental to nature and physical existence.
Gist of Idea
Process philosophy is either phenomenological or biological or physical
Source
Nicholas Rescher (Process Metaphysics [1996], 01.10)
A Reaction
Rescher says Whitehead combines all three, but he himself opts for the third, which strikes me as much the best version. The others are potentially both dualist and idealist.
Book Reference
Rescher,Nicholas: 'Process Metaphysics' [SUNY 1996], p.22