§20. Temporality [415-416]

it is, for example, a hammer, and then in addition something "with which to hammer." Rather, what and how it is as this entity, its whatness and howness, is constituted by this in-order-to as such, by its functionality. A being of the nature of equipment is thus encountered as the being that it is in itself if and when we understand beforehand the following: functionality, functionality relations, functionality totality. In dealing with equipment we can use it as equipment only if we have already beforehand projected this entity upon functionality relation. This antecedent understanding of functionality, this projecting of equipment onto its functionality character, we call letting-function. This expression, too, has its ontological sense suited to the present context of discourse. In hammering we let the hammer function with something. The wherein of our letting-function is that for which the equipment is destined as such; the for-which characterizes this specific equipment as what and how it is. We are expectant of the for-which in using the equipment. "To let function in something" means expectance of a for-which. Letting-function, as letting-function-in, is always at the same time a "letting-function with something." That with which there is functionality is in each case determined via the for-which. Expecting the for-which, we retain the with-which in our view; keeping it in view, we first understand the equipment as equipment in its specific functionality relation. Letting-function, that is, the understanding of the functionality which makes possible an equipmental use at all, is a retentive expectance, in which the equipment is enpresented as this specific equipment. In expectant-retentive enpresenting, the equipment comes into play, becomes present, enters into a present [Gegen-wart]. The expecting of the for-which is not a contemplation of an end and much less the awaiting of a result. Expectance does not at all have the character of an ontical apprehension; nor is retention of the wherewith a contemplative dwelling with something. This becomes clear if we bring to conscious realization unconstructively an immediate employment of equipment. When I am completely engrossed in dealing with something and make use of some equipment in this activity, I am just not directed toward the equipment as such, say, toward the tool. And I am just as little directed toward the work itself. Instead, in my occupation I move in the functionality relations as such. In understanding them I dwell with the equipmental contexture that is handy. I stand neither with the one nor with the other but move in the in-order-to. It is for this reason that we proceed in order in dealing with things-we do not merely approach them as they lie before us but have commerce with them as they exhibit themselves as equipment in an equipmental contexture. Letting-function, as understanding of functionality, is that projection which first of all gives to the Dasein the light in whose luminosity things of the nature of equipment are encountered.

Basic Problems of Phenomenology (GA 24) by Martin Heidegger