Phenomenology of Spirit, Preface, paragraph 64

A difficulty which should be avoided consists in mixing up the speculative with the argumentative manner, when what is said of the subject has at one time the significance of its concept, and at another time the significance of its predicate or accident. The one mode of thinking interferes with the other; and only that philosophical exposition can manage to become workable [plastisch] which resolutely excludes the ordinary way of relating the parts of a proposition.