Kim, Eun-Joong. “Theories of Plato's eidos - Individual Things and Whitehead's Eternal Object - Actual Entity.”  The Journal of Whitehead Studies 3 (2000): 31-50.

Abstract

The origin of Whitehead's criticisms on the substance-attribute structure and the fallacy of misplaced concreteness lies in Plato's dualism of eidos-matter or eidos-individual things. The Greek thinking invited ousia-property scheme in elucidating individual things through the use of predications, and Plato adopted it to develop eidos-individual things system. Aristotle, then, succeeded and expanded it as eidos reduction theory. This line of tradition has evolved into the problem of mind-body dualism in modern philosophy. Whitehead, however, indicates the sphere of mind or eidos from this reduction process as the fallacy of misplaced concreteness. Whitehead attempts to resolve the fallacy by introducing the concepts of actual entity and eternal object: He strives to rectify Plato's eidos-individual things scheme by reiterating that the actual entity is prior to the dualistic scheme of mentality and materiality. Plato's eidos- individual things system is deductive in which many come from one, whereas Whitehead's becoming of actual entity is inductive in which one comes from many.

Whitehead eliminates the elements of inevitability by saying that the act of choosing one depends upon the choice that the actual entity makes. In contrast to Plato's eidos which is the ontological ground of particular things, Whitehead's eternal object is the potentiality for the actual entity. There subsists a presence of reality in Plato's eidos in this respect. Whitehead, however, does not introduce the sense of reality to the concept of eternal object, which allows one to remain independent from the deductive thinking conformity that constrains philosophers. Whitehead asserts that the knowledge of eternal object is realized through the abstraction from concrete things, rather than by recollecting or hypothesizing as in Platonic tradition. In summary, the Whiteheadian theory of actual entity-eternal object primarily attempts to rectify the fallacy of misplaced concreteness that originates from the Platonic tradition of dualism. Furthermore, it seeks a way to unify the dualism of substance-attribute.  [Abstract from The Journal of Whitehead Studies]