"Use Your Common Sense"

I've heard it thousands of times. People use it like a prayer, hoping to ward off stupidity, as if repeating it would bring about enlightenment: "Use your common sense." But what does this really mean? Let's take a look.

Use: it's a command. It commands somebody to execute an action, in this case, to make use of common sense.
Your: refers to the common sense that belongs to the person the speaker is talking to ("you").
Common: refers to something that is shared, not-noble, not special, that happens regularly.
Sense: refers to the ability to perceive something, physically or mentally, or what is mentally perceived using such ability.

Having these words in mind, let's re-construct (or deconstruct) the meaning of the phrase. It seems the speaker is commanding the hearer to make use of an ability they both share, that is not special, belongs to commoners or that happens regularly.

It can be inferred that the action (use) does not happen regularly, because it has not happened. It could also be said that it is probably special, since the speaker has it and the hearer doesn't. The speaker probably doesn't refer to an ability commoners have because it seems as if this ability was a good thing, and seldom does one refer to oneself as a commoner---unless one is running for political office in the United States. And it is obviously not shared, since what the speaker seems to understand clearly is beyond the grasp of the hearer at that point in time. We must accept, then, that this sense, called "common sense," is not really common.

The use of the word "your" along with "common" does not make sense. If it were common, it would be ours, not yours.

Gramatically, the sentence seems to be flawed, but language doesn't necessarily depend on grammar. It depends on people, the context and the way people use it.

When the speaker commands the recipient to make use of his sense, he is really telling him to make use of a sense that belongs to the speaker---probably some sort of specific Weltanschaung (world-view). By adding the word "your" to the sentence, the speaker implies that this Weltanschaung is already part of the hearer, or that it should be. Moreover, because this sentence is generally used in exasperation, it implies that whoever is listening should see the world the way the speaker sees it.

Conclusion: when someone tells you to "use your common sense," they are telling you to see the world the way they do, and that if you don't you're lacking sense.

Thinking about Common Sense

I always get confused when people say “common sense.” What is common sense? Is it common? Is it a sense? Confused by the blithe use of the phrase, I decided to use what people might call “a common-sensical approach” to the meaning of “common sense.”

First, I decided to establish what it is that people think when they talk of common sense. It seems to me people think of “sound judgment,” “logic” and “reason” as a synonyms for common sense. Using reason/logic, I decided I would analyze the two words that make the phrase up and see what would I find.

Common: shared, not-noble, not special, happening regularly.
Sense: the ability to perceive something, physically or mentally, or what is mentally perceived using such ability.

According to these descriptions, the phrase “common sense” should mean something along the lines of “a regular, shared and not-special way commoners have to perceive mentally or physically.” In other words, the way common people perceive--and thus react to--the world around them.

Is it logical? It might be, but not necessarily so. By definition, common sense needs only be “common,” not follow reason. In practice, however, logic and common sense do seem to overlap. It is logical to not stab yourself in the eye, because that would damage the eye, resulting in physical pain and possible loss of sight, thus causing avoidable damage to yourself. Common sense would dictate pretty much the same thing.

But what Joe and his friends might consider to be sound judgment might not be to Jack and his buddies across the bridge. Joe and his friends might root for the Yankees, and might think it a good idea to donate money for a new statium for them to play in. Jack and his buddies might be Mets fans, and donate money for a Mets stadium. Logic dictates that being a fan is stupid, because it’s uncorresponded, unconditional love (illustrated by the current management of the new stadiums).

This way of thinking of common sense, then, seems to cease to be common across peoples in the case of baseball. There are cases, however, in which this understanding of common sense is common across different types of people. Although different cultural contexts provide different starting points for people to think about the world and perceive it, there are human instincts that exist independent of those. Some of these are avoiding pain, seeking pleasure, fear of death. When we act instinctively, we act through common sense.

Is acting instinctively, then, logic? It depends. Instinct keeps us alive. But is living logic? Probably not, though nobody knows for sure. Not even a purpose for life has been established that is common to all people.

But obviously "common sense" is just a phrase that can mean whatever we want it to mean, just like we arbitrarily say Zs mean sleep and HAs mean laughter.

Conclusion: although we think of common sense as meaning 'sound in judgment' (which probably is arrived to by logic or reason), common sense really means proceeding in a way consistent with our instincts, and this may or may not be logic.