b) Return to the productive comportment of the Dasein toward beings as implicit horizon of understanding for essentia and existentia
Among the concepts that are characteristic for essentia, we mentioned μορφή, εἶδος (forma), τὸ τί ἦν εἶναι (that which a being already was, the essence) or the γένος, and, in addition, φύσις (nature), ὅρος, ὀρισμός (definitio), and οὐσία (essentia). We begin by considering the μορφή concept. What determines the thingness, Sachheit, in a being is its figure [Gestalt]. Something takes this or that shape, it becomes such and such. The expression is drawn from the sphere of sensory intuition. Here we first think of spatial figure. But the term μορφή should be freed from this restriction. What is intended is not just spatial figure but the whole characteristic form impressed on a being from which we read off what it is. We gather from the shape and impressed form of a thing what the case may be with it. Forming and shaping lend its own peculiar look to what is to be produced and has been produced. Look is the ontological sense of the Greek expression εἶδος or idea. In the look of a thing we are able to see what it is, its thingness, the peculiar character impressed on it. If we take a being as encountered in perception, then we have to say that the look of something is based on its characteristic form. It is the figure that gives the thing its look. With regard to the Greek concepts, the εἶδος, the look, is founded, grounded, in the μορφή, the form.
For Greek ontology, however, the founding connection between εἶδος and μορφή, look and form, is exactly the reverse. The look is not grounded in the form but the form, the μορφή, is grounded in the look. This founding relationship can be explained only by the fact that the two determinations for thingness, the look and the form of a thing, are not understood in antiquity primarily in the order of the perception of something. In the order of apprehension I penetrate through the look of a thing to its form. The latter is essentially the first in the order of perception. But, if the relationship between the look and the form is reversed in ancient thought, the guiding clue for their interpretation cannot be the order of perception and perception itself. We must rather interpret them with a view to production. What is formed is, as we can also say, a shaped product. The potter forms a vase out of clay. All forming of shaped products is effected by using an image, in the sense of a model, as guide and standard. The thing is produced by looking to the anticipated look of what is to be produced by shaping, forming. It is this anticipated look of the thing, sighted beforehand, that the Greeks mean ontologically by εἶδος, idea. The shaped product, which is shaped in conformity with the model, is as such the exact likeness of the model.