Did not Galileo grind his own lenses for his telescopes? Did not Yogi Berra state that in theory there's no theory between theory and practice but that in prac

Did not Galileo grind his own lenses for his telescopes? Did not Yogi Berra state that in theory there's no theory between theory and practice but that in practice there is? Is an abacus useful in Computer Science or is it an impediment to purely conceptual algorithmics? I use Linux precisely because it enables good Computer Science, as telescopes enable good astronomy, as particle accelerators enable the realisation of the prediction of the Higgs Boson.