Some interesting examples of tacit knowledge are described in a remarkable book by David Freeman Hawke who writes a history of “mechanicians”. Not engineers as we know them today nor mechanics but unschooled masters of the use of tools found in the eighteenth and nineteenth centuries. The mechanicians could design new machines and invent marvelous mechanical contrivances yet were largely unknown. They were not mathematicians or scientists and possessed no fancy theories from school, yet had learned from experience a most remarkable set of skills. Hawke describes the stories told by George Sturt who ran a wheelwrights shop in the late nineteenth century. Tales of how these masters of wood came into their skill after seven years or more of apprenticeship. Reasoned science was not involved; instead they lived up to the acquired wisdom of the time. A stage was reached when the eyes and hands were left to a remarkable cleverness with no guide to follow. A good wheelwright knew by art rather than reasoning how tight a tyre should be made for a five foot wheel. It was a feeling in his bones. Sturt knew what convexity was required for a wheel yet neither he nor any other skilled workers in the ship could explain why it had to be that way. A wheelwrights brain had to fit itself to the task by growing into it. He said his own eyes knew through the feeling in his hands the difference between ash “tough as whipcord” vs ash that is “doaty” or “biscuit” yet he could not teach or explain this to anyone. With all the elaborate training systems of today we have lost touch with this side of education, the tacit side so well explained by Michael Polanyi.