“The Being of those entities which we encounter as closest to us can be exhibited phenomenologically if we take as our clue our everyday Being-in-the-world, which we also call our ‘dealings’ in the world and with entities within-the-world. Such dealings have already dispersed themselves into manifold ways of concern. The kind of dealing which is closest to us is as we have show, not a bare perceptual cognition, but rather that kind of concern which manipulates things and puts them to use; and this has its own kind of ‘knowledge’. The phenomenological question applies such concerns. (…) they are simply what gets used, what gets produced, and so forth. As entities so encountered, they become the preliminary theme for the purview of a ‘knowing’ which, as phenomenological, looks primarily towards Being, and which, in thus taking Being as its theme, takes these entities as its accompanying themes”.
Being and Time - Martin Heidegger