How common is common sense?

I've always thought that the idea behind common sense is that there is a well of information out there somewhere that all humans are somehow tapped into. Or even something genetically transmitted from parents to children.

At least that's how we behave when we run into someone who we think lacks in that department. We wonder, 'where was this person raised, in outer space?'

So I've been thinking about what goes into what we consider common sense. I tried to think of examples of what I consider common sense and see how and where I learned them.

The first one that sprung to my mind was the 'make sure to be aware of your surroundings when you walk' idea. Anyone who's been raised in a city knows that it's crucial for your personal safety to know this bit of common sense. It's extremely common, however, for a small town person to not have this bit of information, which is something they quickly learn once they've been in the city for a few days and are mugged. (Okay, so I'm exaggerating a bit.) It looks like we pick up some amount of common sense from the environment in which we're raised.

On a similar topic, I've worked with a girl who never notices subtle hints. If I'm upset and ask a friend to go for a walk, she'd jump in and say "Can I come along, too?" Not that we didn't like her or enjoy her company, but she didn't seem to realize when it wasn't really appropriate for her to invite herself. I kept wondering how she'd managed to make it through her teenage years without having been totally burnt. Learning when to talk and how to act is a series of common sense tricks we pickup from our family and surroundings. These bits of information sometimes sting so hard that we never forget how we developed this piece of "common sense." (And we rarely forget the "friends" who taught us this lesson first hand.)

Another example I came up with was building common sense through education. As I learned American Sign Language, many of the signs seemed common sense to me and so I'd retain them easily. Same for Japanese grammar. Even math felt like common sense to me. It seemed the more I learned, the more stuff appeared to be common sense.

Here's what I think it all comes down to: common sense is a combination of what you learn from your environment, family, friends, books, school and all your deductions from this knowledge.

Next time you meet someone who seems to lack what you consider common sense, remember that it's not a centralized resource pool in which we can all tap.

Just like most anything else in life, it stems from personal experience.

Previously? The Itch.