I am currently reading an article by Martin Heidegger, entitled 'The Origin of the Work of Art'. Heidegger begins his discussion with three prevalent interpretations of 'thingness of things'. He also classifies his own quest for the 'thingness of things' into three categories, the thingness of mere things, the thingness of an equipment and the thingness of a work (of art).
Under the three prevalent interpretations, Heidegger notes that the first two are of less use in the study of aesthetics. Firstly, the a thing is (traditionally) defined as something carrying several predicates. A granite, for example, is hard, brittle and with many other properties. This schema of assigning the predicates to a thing is considered an anomaly that occurred when Greek thought was borrowed by Romans. Heidegger also delineates a parallel between the tendency of adding predicates to things in real world and the subject-predicate system used in language. This system of language, as it is derived from the Greek, is already a representation, he adds. What is exactly at work is a forcible act that claims to bring the thingness of a thing to light, which nevertheless is unsuccessful.
In the second interpretation, tradition has it that opening up the senses to the world of things will help us find the thingness of thing. However, Heidegger argues that even if we hear the sound of a door shutting down, it is not the door that is coming to our mind, but the whole image of a neighbourhood area. Further, it is not the thingness of a material that strikes us when we hear a Mercedez passing along the road, but the image of the Mercedez itself. While the first interpretation thrusts the thingness on us, the second interpretation keeps the thing at arm's length.