Rationalism, i.e., the philosophy of concept and rationality, the philosophy of things and lifeless immobility, is wholly connected with the law of identity and can be succinctly characterized as a homoiousian philosophy. It is a fleshly philosophy.
By contrast, Christian philosophy, i.e., the philosophy of idea and reason, the philosophy of persons and creative acts, is based on the possibility of overcoming the law of identity and can be characterized as a homoousian philosophy. It is a spiritual philosophy.
The tendency to pure homoiousiansism as to its limit determines the history of modern philosophy in Western Europe, whereas the attraction to pure homoousianism constitutes the distinctive nature of Russian (and of all Orthodox) philosophy.
Fr. Pavel Florensky