Against metric units: a harangue
Here’s the diatribe I promised in my previous blog about the EU Referendum…
During the late 1960s and early ‘70s Britain faced the prospect of replacing her traditional “imperial” system of weights and measures with the metric (decimal) system used by all our EEC (now EU) partners. The arguments adduced in favour of the change were, in a nutshell: the simplicity, universality and memorability of the metric system. Those of us who resisted the change, mostly on the grounds of custom and tradition, were brushed aside and in some cases punished by force of law for continuing to use imperial units.
I was antagonistic to metrication then and I still am. People wonder at my attitude, particularly since during my clinical and scientific career I had no problem with metric (SI) units in the laboratory or in medical practice. However, in science and medicine we’re dealing dispassionately with objective evidence, so a system or weights and measures divorced from everyday human experience and from tradition is not only acceptable but also desirable, especially since it’s convenient and easy to use. Outside the laboratory, living and travelling, shopping and cooking, we’re not dealing dispassionately with objective evidence but emotively with personal human experience, which is enriched by tradition and memory – and vitiated by the objective and dispassionate.
As an example of metric units, consider the metre itself. Let’s forget the 1793 definition (one ten-millionth of the distance from the equator to the North Pole), which proved to be a mis-measurement, the 1889 ‘metre bar’ and its amendments, and the extraordinary 1960 definition (1,650,763.73 wavelengths of the orange-red spectral emission line of krypton-86 in vacuo), and consider instead the currently accepted definition: the distance travelled by light in 1/299,792, 458 of a second. How many people could rattle this off from memory? I had to look it up again in order to write this blog. So much for simplicity and memorability.
But that isn’t my main objection to the metre. I resent being asked, in my day to day life, to deploy a unit so utterly divorced from my physical and sensory experience. Weights and measures should resonate with the familiar, not dictate to us from a cold indifferent tower of objectivity. They should be reasonable, not rational. If I walk a mile (is it really simpler and more convenient to say “1609.3636 metres” instead of “one mile”?), that’s one sort of experience; if I climb a mile-high hill it’s another. The latter is more physically demanding than the former, no matter how fit and athletic you are. So is it reasonable to use the same unit for horizontal distance as for vertical distance? Surely it’s far more sensible to use miles, yards etc. for the former and feet for the latter. The contrast of units reflects the difference of experience.
(I believe British people have never truly accepted the metre. When they speak of ‘kilometres’ they pronounce the word ‘kilOmetres’, not the more natural ‘KILometres; the pronunciation of words adopted into English evolves towards a stress on the first syllable. Really – ‘kilOmetres’? Like ‘centImetres’ instead of CENTimetres or ‘millImetres’ instead of MILLimetres? Give me a break.)
Another similar objection concerns the way our minds work. We naturally relate weights and measures to each other in terms of halves, quarters etc.; roughly speaking, our minds relate units on a log to the base two principle, not a log to the base ten principle – pounds, half pounds, quarter pounds, ounces (an ounce being a sixteenth of a pound); miles, half miles, quarter miles, furlongs etc. Weights and measures should be accommodated to our minds, not the converse. So besides the greater convenience of proper units (it’s far more sensible to ask for a quarter pound of cheese than to demand 113 grams of cheese, or whatever the equivalent is), they’re also far more human.
And then there’s the way tradition has entered the language. We might speak of someone “inching his way along the narrow path” but hardly of “twenty-five-point-four-millimetring his way along the narrow path”. A cemetery beside a church is often, poetically, described as “God’s acre”; I can’t imagine it being called “God’s 0.4047 hectares”. And while we might say of a chancer “Give him an inch and he’ll take an ell”, we’re unlikely to say “Give him 25.4 millimetres and he’ll take 457”. A cricket pitch is 22 yards long, not 20.99 metres. And so on.
The metric system is therefore alien to our tongue and to our customs. Ipso facto, its adoption divorced us from a significant part of our tradition, and with it went much of recent generations’ recognition of and respect for our roots. It’s no coincidence that around the time the metric system was adopted in the UK, history teaching in our schools was largely reduced to twentieth century history. Abandoning our traditional system of weights and measures, we cut off our own roots, and any society that does so is at risk. To divorce yourself from the past is to face an uncertain future.
This isn’t sentiment. It isn’t impractical. In the past, not least during the late eighteenth and nineteenth centuries, Britain led the world in science and engineering. Did our great thinkers and innovators use metric units? No, of course they didn’t. They used the familiar, practical units they’d learned from cultural tradition and everyday practice. If imperial units were good enough for Watt and Stevenson, Dalton and Faraday, aren’t they good enough for us? Well, I don’t compare myself with people of such stature, but imperial units are good enough for me.
I’ll end this harangue by attacking a unit that especially sets my teeth on edge. When the metric system was foisted on the UK we were told to use the centigrade rather than the Fahrenheit temperature scale. Well, okay – though for air temperatures, Fahrenheit is the more sensitive scale so it better reflects human perception and experience than does its replacement. But then some ignorant fool decided we shouldn’t say “centigrade”; we should say “Celsius” instead. Have these metrication clowns no knowledge at all of the history of science? Yes, Celsius was one of the first people to devise a temperature scale with the zero and one hundred degree points set by the boiling and freezing points of water at sea-level atmospheric pressure – but his scale was the inverse of centigrade. Water freezes at zero centigrade, which is 100 degrees on Celsius’s scale. It boils at 100 degrees centigrade, zero on the Celsius scale. So properly speaking, if we have a pleasantly warm day with a temperature of seventy degrees Fahrenheit, it’s twenty-one centigrade and seventy-nine Celsius. When the weather forecaster tells us it’s twenty-one Celsius, therefore, she means – or ought to mean – that the air temperature (seventy-nine degrees centigrade) will be incompatible with most forms of terrestrial life. Anyone for sunbathing?