Common sense means paying attention to the obvious. This is not as easy as it sounds, because we all have vivid imaginations, and we tend to get lost in our fantasies.
When fantasy replaces common sense, life becomes farcical and even tragic. Life is a series of ordinary events that follow the laws of logic and probability. These ordinary events are indifferent to our fantasies and require the careful, accurate navigation of common sense.
I learned the lesson of common sense as a third-year medical student. I was doing an internal medicine rotation at a veterans hospital and working with interns, residents, and attending physicians.
One day, on morning rounds, we examined a patient with a black tongue. The intern assigned to that patient had researched all the causes of a black tongue and was eager to demonstrate his new knowledge. As the intern started to lecture us, the attending physician interrupted him and asked the patient if he uses black cough drops. The patient smiled, opened the drawer of his night table, and took out a package of Smith Brothers black cough drops.
The intern's face turned red, and we all laughed. The intern was so focused on being a doctor, that he forgot to ask his patient an obvious question. It's been over 40 years since I was a third-year medical student, but I still have a vivid memory of that day and that lesson: use common sense, and pay attention to the obvious.
Being a physician has taught me the lesson of common sense again and again. Eventually, I realized that we all lack common sense, and this is why we can't solve our problems. So let's seek common sense and apply it to everything, because knowledge plus common sense is wisdom, but knowledge minus common sense is nonsense.