"He's Got No Damn Common Sense" said Sergeants of Soldiers, But It's True of All of Us

By the time Thomas Paine wrote Common Sense in 1775, 

the idea of common sense was already disappearing. 

"He's got no damn common sense," is a lament I heard all through my Cold War military career in the 1970s and 80s.  Frustrated sergeants, including me, lamented dealing with soldiers who knew nothing about wrenches or lieutenants who got lost on every field exercise.  

In Germany in 1977, I got a new replacement crewman named Brian. Every new tank crewman starts as a driver, which presumes some mechanical ability.  Brian had never owned a car and never used wrenches before joining my crew.  He became a legend (in the worst way) when I had to show him how to use an open-end wrench in a tight space.  

The head of an open-end wrench is slightly offset. You turn turn a bolt a few degrees, turn the wrench over and turn a few more.  It's slow, but you can remove or tighten a bolt in a tight or covered space by flipping the wrench.  This process mystified Brian.  He got it eventually, but his fellow crew members made merciless fun of him for not knowing how an open-end wrench worked.  

Knowing or catching on quickly to this kind of process is referred to as having common sense.  At the time, I was sure Brian lacked common sense.  

But in her most important philosophical book The Human Condition, Hannah Arendt says that by the time Brian was accused of lacking common sense, the whole culture had lost what was common sense across the world.  

Arendt says that the rise of modern science, beginning with Galileo's invention of the telescope, showed we could no longer trust our senses.  

Common Sense took the experience of our five senses and gave them a unified frame of interpretation.  But Galileo showed us that what our senses can be completely wrong even when we simply look at the night sky.  In her book Being Wrong Kathryn Schulz explains how thoroughly wrong we can be when all of our senses tell us we are right. 

"Step outside...in someplace truly dark: the Himalayas, say, or Patagonia, or the north rim of the Grand Canyon. If you look up in such a place, you will observe the sky above you is vast and vaulted, its darkness pulled taut from horizon to horizon and perforated by innumerable stars.  Stand there long enough and you'll see this whole vault turning overhead, like the slowest of the tumblers in the most mysterious of locks. Stand there even longer and it will dawn on you that your own position in the spectacle is curiously central. The apex of the heavens is directly above you. And the land you are standing on--land that unlike the firmament is quite flat, and unlike the stars is quite stationary--stretches out in all directions from a midpoint that is you. 

"It is, of course, an illusion: almost everything we see and feel out there on our imaginary Patagonia porch is misleading.  The sky is neither vaulted nor revolving around us, the land is neither flat nor stationary, and, sad to say, we ourselves are not the center of the cosmos. Not only are these things wrong, they are canonically wrong. They are to the intellect what the Titanic is to the ego: a permanent puncture wound, a reminder of the sheer scope at which we can err. What is strange, and not a little disconcerting, is that we can commit such fundamental mistakes by simply stepping outside and looking up."

Arendt says that when we cannot trust the most obvious perception of our sense, we eventually lose the common sense that still is valued in its absence a half millennia later. If physics on a cosmic scale says we are wrong when we perceive the sun circling east to west every day, it's worse at the atomic level.  Who can really believe an oak table is as much empty space as the night sky.  The solid hardwood of every oak plank at the atomic level protons, neutrons and electrons and a whole bunch of nothing. And those atoms are strung together held by charge with mostly empty space in every direction.  

Poor Brian could blame every physicist from Galileo Gallilei to Albert Einstein to Richard Feynman to Roger Penrose for proving that nothing that his senses experience is as it appears. 

The Cold War sergeants' lament that "none of my soldiers has a lick of common sense" was more true than he knew.  The sad thing is, that old sergeant did not have much common sense in the traditional sense either.