“In ‘Being and Time’, Heidegger observed that many of our tools are invisible to us. We do not notice the racket as we hit the ball, for example. He called this ‘ready-to-hand’. When ready-to-hand, the tool is no longer a things on its own. Instead it is intertwined with us - with our purposes and practices, motives and expectations.
Heidegger argued that when a tool fails, it becomes visible again”