  The Phaedo (especially the Affinity Argument, 78b-84b) also points up a host of features, usually found in pairs, which differentiate particulars from Forms. Forms are immaterial, non-spatial and atemporal. Particulars are material and extended in space and in time. Forms do not change and may not even be subject to Cambridge-change, i.e. relational changes involving, for instance, a soul cognizing them at various moments. Particulars change, may even be subject to change in any respect, and may even be subject to change in every respect at any given moment, i.e., total Heraclitean flux. Particulars are complex or multi-form (polyeidetic) composites (suntheton), whereas Forms are pure, simple or uniform (monoeidetic, hen). Particulars are the objects of the senses and of belief. Forms are the objects of knowledge, grasped by the intellect through definitions, dialectic, or otherwise. Particulars appear, and perhaps are, both F and not-F for some property F: particulars suffer from the compresence of opposites. The Form of F cannot be conceived to be not-F (and perhaps is never not-F). Hence the Form, The F Itself, does not suffer compresence (at least with respect to being F).