Deconstructionists in particular, among the academy, heaped scorn upon the notion of common sense, considering it to be simply another means that powerful people employ to keep themselves in power. Of course, they considered everything to be a means of powerful people keeping themselves in power, except of course their own doctrine, a rhetorical bludgeon which they employed as a powerful means of assuming and then keeping themselves in power.
There is much folk wisdom that is quite wrong, to be sure, but it is important to remember where much of it comes from: several-thousand years of trial and error by humans very much like ourselves, in genetic terms at the very least.
Millions of people, after all, have encountered the same problems most of us tend to run into, or ones very like them (carriage accidents, for example, analogous to our automobile mishaps), and tried all sorts of ways of dealing with them. Some worked, some didn't, some were partially successful, and some created further disasters. These people told one another about these incidents and their results, and often other people witnessed them, and thus a huge amount of data came into being and was plugged into civilization's vast store of memories.
With such a large amount of innormation being accumulated by so many people, there is a good chance that many truths will be found. Naturally, some of these will be difficult to prove in strictly logical terms, because so much innormation and reasoning is necessary to the normation of an explicit logical argument for each of them. We know these truths through experience and intuition, as our brains work faster than even the brightest among us can explicitly reason. Thus these are perfectly legitimate ways of obtaining knowledge.
Hence, before discarding any proposition that involves no clear contradictions of known facts or internal logic, it is important that we first try to find some explanation of why the principle is believed to be true. Of course, we should always be willing to test all things, and must be quick to discard those that prove untrue. That is only common sense.
But we should always have respect for propositions that prove true even though we aren't quite sure why.
Which brings us to a fascinating article in the New York Times on the matter of colic in infants. Colic is the prolonged, unexplained crying that some babies habitually do during the early months of their lives. Scientists, the article notes, are in great disagreement over the causes of colic, and equally discordant over what parents should best do about it.
What is particularly interesting about this as regards common sense is the solution suggested by a doctor who has studied the problem and come up with a five-step treatment that seems to do wonders in quelling infants' crying jags. It is an excellent case of human experience over the ages being codified into common-sense truths that are nonetheless true despite being difficult to prove in logical, scientific terms. Here's how the Times article describes it:
"Dr. Karp's solution: recreate for infants sensations in the womb to help them stay calm.
"In the womb, the soon-to-be-born infant is packed tightly, head down in fetal position, with lots of jiggling and a whooshing sound -- blood flowing through the placenta -- that is louder than a vacuum cleaner. According to Dr. Karp, these conditions put the fetus into a trance.
"'Fussy babies would really benefit if they could hop back inside the uterus whenever they get overwhelmed,' Dr. Karp said. Paradoxically, their distress can also stem from being understimulated. 'Our culture believes in the strange myth that a baby wants to be left in a quiet dark room,' he said. 'But what is this stillness for a newborn baby? It might be aversive, since the womb is jiggly and noisy.'
"To calm a baby, Dr. Karp sets out five maneuvers that he says will touch off a calming reflex and put the infant to sleep. They must be carried out progressively, as a kind of dance, to work their magic, he said."
These include swaddling, holding the infant in one's arms with the baby on its side or stomach, making "a very loud shushing noise delivered directly into the baby's ear," jiggling the baby, and allowing the child to suck on a finger or other nonnutritive source, according to the Times article.
And these are, of course, exactly the things that parents from time immemorial have used in quieting babies.