C'mon, That's Just Common Sense!
When someone says to you, "C'mon, that's just common sense?", do you interpret the remark as "Hey, don't be stupid!"?
What exactly is "common sense"?
Can you define what exactly is "common sense"? Ponder for a moment before reading any further and see if you can!
The Merriam-Webster Dictionary says that "common sense" is "sound and prudent judgment, based on a simple perception of the situation or facts".
A more lucid, but not necessarily more accurate, definition would be "sound judgment, not based on specialized knowledge". Hence, common sense is supposed to be held by any reasonably mentally-competent person and is therefore supposedly widespread (i.e. "common"). This being so, it is therefore understandable why anyone should feel insulted if you were to say, "C'mon, that's just common sense!" That person may take it as a personal attack, implying below average intelligence, if he or she fails to come to the same conclusion as you do.
To Harriet Beecher Stowe, author of Uncle Tom's Cabin, however, sound judgment is not enough. She says: "Common sense is seeing things as they are; and doing things as they ought to be". To me, this definition is even more confusing than what the Merriam-Webster Dictionary offers, simply because we may be looking at the same thing but what you see is not what I see. A man may look at a crisis and see it as a problem, while another man may see it as an opportunity. Wikipedia says that identifying particular items of knowledge as "common sense" is difficult.
Furthermore, Stowe's definition implies that to be considered as having common sense, having sound judgment is not enough, one must also do what is right. By her definition, therefore, a smoker who is well-aware of the ill-effects of smoking is not sufficient to be considered as having common sense because his or her judgment is not followed by action.
From the foregoing, it is therefore obvious that the term "common sense" is not a precise language and may mean different things to different people. In the words of Sophia Rosenfeld, a historian at the University of Virginia and author of the book, Common Sense: A Political History, common sense is a "slippery" idea. Is it any wonder, then, that philosophers and scientists tend to avoid using the term in favor of some more specific term, whenever possible.
Etymology of the term "Common sense"
The origin of the term "common sense" can be traced back to Aristotle who defined it as the way in which one receives sensation. His use of the term obviously differs from current views in that it was not concerned with belief, or the wisdom held by many.
In her book, Common Sense: A Political History (2011), Sophia Rosenfeld claims that "common sense", as we understand it today, was invented by scientists, philosophers, and politicians, with the latter constantly appealing to it in their arguments because democracy itself was founded on a faith in common sense.
Bazaar mathematics or just bizarre mathematics?
A stationery shop displayed a big cardboard poster, saying:
1 copy: 10 cents
100 copies or more: 8 cents a copy
I walked into the shop to make a duplicate copy of a technical manual for my company. After the photostating was done, the shop assistant told me there were 94 copies and so the price was $9.40. I said, "Shouldn't it be $8.00?" The assistant said "No, one copy is 10 cents because you have less than 100 copies."
On hearing the conversation, the lady boss came over. On being told about the price dispute, she told me, "This is our rule. Anything less than 100 pages is 10 cents per copy. I just charged a guy $9.90 this morning for 99 pages, so what is your 94 pages?" I replied, "Okay then, print for me another 6 pages." The shop assistant looked at me and said, "Which pages?" I said "any page". The boss looked at me in horror and said, "I know you don't need those 6 pages. Okay, I will give you an exception this time, but not the next time!"
Common sense is not so common
"Common sense is not so common", says Voltaire. Ralph Waldo Emerson shares the same sentiment when he says: "Common sense is as rare as genius.” So, if common sense is not common, why then do we call it "common sense"?
As mentioned above, "common sense" is supposedly held by all reasonably mentally-competent person and hence, it is supposedly widespread. Yet what is common sense to one person may not necessarily be common sense to another person, simply because one's judgment is based on one's knowledge and experiences. Since common sense is based, in part, on one's experiences, it therefore implies that common sense is not always universal and may differ from culture to culture. Slurping your soup in Japan, for example, is considered good manners, especially if you are a guest, because it indicates that you are enjoying your meal, but try doing it in the West and you may well meet with horrified stares! As such, the term "common sense" can be a cause of conflict when one person's idea of "common sense" conflicts with that of another person. Let us take a look at the following example that actually happened to me some years back: