I will not comment on these quotes at the moment. I only record them for reference. Each is from Personal Knowledge, by Michael Polanyi.
When we use a hammer to drive in a nail, we attend to both nail and hammer, but in a different way. We watch the effect of our strokes on the nail and try to wield the hammer so as to hit the nail most effectively. When we bring down the hammer we do not feel that its handle has struck our palm but that its head has struck the nail. Yet in a sense we are certainly alert to the feelings in our palm and the fingers that hold the hammer. They guide us in handling it effectively, and the degree of attention that we give to the nail is given to the same extent but in a different way to those feelings. The difference may be stated by saying that the latter are not, like the nail, objects of our attention, but instruments of it. They are not watched in themselves; we watch something else while keeping intensely aware of them. I have a subsidiary awareness of the feeling in the palm of my hand which is merged into a focal awareness of my driving the nail (p. 55).
Subsidiary and focal awareness are mutually exclusive. If a pianist shifts his attention from the piece he is playing to the observation of what the is doing with his fingers while playing it, he gets confused and may have to stop. This happens generally if we switch our focal attention to particulars of which we had previously been aware only in in their subsidiary role (p. 56).
And he adds,
Our subsidiary awareness of tools and probes can be regarded now as the act of making them form a part of our own body…We pour ourselves out into them and assimilate them as parts of our own existence. We accept them existentially by dwelling in them (p. 59).