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.

A discussion with one of my book reviewers resulted in an ongoing exchange about the utility of memorization in learning. I express general disapproval of rote memorization in the book which elicited alarm and disagreement from the reviewer. The topic quickly grew to one that has interesting ramifications that I shall ruminate upon here. Why would memorization be contraindicated for learning? As a former college physics teacher I recall the usual plea from students who wanted to know what formulas they needed to memorize for the next test. This question is a red flag for me as memorization suggests the mindless jamming of some collection of meaningless letters into their memory. My reply to the students was always along the lines of asking them not to memorize the formulas but instead to KNOW them. What does that mean? Personally I have always disliked the process of memorization (never did well in foreign languages) and during my years of study I would count on the repetitive use of the equations (refering to the text) within a problem solving setting to gradually get them into my head. The formulas are relationships between variables hence constituted comprehension of a relationship, a concept, an idea. I would end up knowing the formula as a short hand expression for a comprehended idea. In that way I never went through a deliberate process of memorization but ended up “knowing” the formula. When I counsel against memorization I am not suggesting that formulas should be absent from the mind, after all we need to know stuff and some of the things we need to know are efficiently expressed as a formula. Perhaps some learners find it easier or quicker to begin the process of understanding by rote memorization of a formula that is then used within problem solving contexts hence they too will gradually build around the formula a state of comprehension. I guess I cannot argue that such an outcome is bad, just that I personally choose not to follow that approach. On the other hand the ugly is a state where the formula remains a dead entity, a meaningless collection of letters and symbols into which numbers (found in a problem) are inserted for the purpose of getting an answer (congruent with the one in the back of the book where answers often reside). Current educational practice slams the process of memorization quite hard with phrases such as “drill and kill”. This attitude describes an ugly outcome where learners become bored with the process of education and hate learning because all they do is memorize and regurgitate. I recall a history class where I was required to memorize the names of the capital cities for each state. After the “drill and kill” procedure I then had to take a regurgitation test linking the correct name of the capital city to the appropriate state name. All this dull cramming seemed as a useless waste of time hence undesirable. I hated doing it. Today I wonder what kind of alternative could replace this onerous task yet end up with the outcome that I indeed KNEW the names of state capitals. How about asking this question: How did each state capital become the state capital and where did the name come from? The process of determining the answer to these questions would be interesting, tell a story, (our minds are well equipped to handle stories) and, although less efficient, would yield the desired outcome. That’s good. The reviewer happens to be a chemist and we both remember the first chemistry course where the symbols representing elements needed to be memorized. This requirement is certainly an example where a down and dirty process of explicit memorization is necessary so sometimes cold hearted memorization is good.