Martin Heidegger, as early as Being and Time, pointed to the semi-transparency equipment attains in use. His analysis of tools pointed out that in use the tool "withdraws' because what is focal is the "work". At the same time, he allowed for the disappearance of such transparency when the tool or instrument breaks down, malfunctions or is missing. In such cases the instrument obtrudes into the telic aim of the user and the functioning of the intentional relation ceases. In Heidegger's analysis the instrument becomes a "thing" and loses its transparency.