Common Sense Says A Lot Of Things. Oh, Yeah.


I was picking up my son from summer camp last year when I saw a woman in Tesla Model S talking on her phone. Now, I don’t know if you’re familiar with Elon Musk’s auto of the future, but the car is so advanced you could probably remote control the ISS from it. With that kind of capabilities, you’d think it was common sense that the native radio in a Model S would have a Bluetooth connection. It should also be common sense that you’d want to have a hands-free device while you’re driving a car in a crowded parking lot with a lot of kids around.

I keep hearing people say, “Common sense isn’t that common.” It’s a great rhetorical argument that doesn’t hold a whole lot of water because common sense is a constantly shifting thing; it’s become nothing more than an argumentative tactic that means about as much as velvet painting of a naked Elvis hanging in the family room.

“Let’s create a common sense plan to do x.” Where x is pretty much anything from fishing for compliments on the Internet to banning Muslims while not banning Muslims.

We tend to think of common sense as innate knowledge – that there are things that are so rational they can’t be assailed logically – but that’s not really accurate. I think the problem is we’ve – as a society – forgotten exactly what common sense even means. The baseline definition of common sense (from is:

“Sound and prudent judgment based on a simple perception of the situation or facts”

Wikipedia expands on this (as it is wont to do), by defining common sense as:

Common sense is a basic ability to perceive, understand, and judge things that are shared by (“common to”) nearly all people and can reasonably be expected of nearly all people without need for debate.”

I’m just gonna toss this out here and say Wiki’s definition is better. But, for the sake of argument, let’s take both of them apart and see what’s inside.’s definition sounds an awful lot like how people see common sense these days. Unfortunately, it’s not really common sense; it’s more akin to making a snap judgement without drilling down into the situation and that takes us from the realm of common sense into the realm of bumper sticker logic.

From there, madness follows.

Look out a window. Any window will do. Unless you’re working in a basement hammering out nuclear missile code, there should be a window handy. What do you see? Trees, birds, mermaids. Does it look flat? Flat-ish? Common sense, according to snap judgement will tell you the planet is flat. I can’t see any curvature, so it’s a sound and prudent judgment that the Earth is flat.

I’ve even got empirical evidence to back it up. I mean, just look outside. It’s obviously flat.


The problem is, the planet doesn’t actually look like this even though there’s a bunch of allegorical data to back it up.

Taking a simple presentation of the situation or the facts is the antithesis of making sound or prudent judgments. It’s roughly analogous to judging a book by its cover or voting for a president because he’s really, really rich.

Wiki’s definition hews closer to a useful definition. Even though most people who will tell you to use common sense are referring to’s definition, Wiki’s definition is what they’re implying – the idea that something is inherently reasonable to a group of people. Unfortunately, one of the reasons Wiki’s definition is better is because it’s narrower; it implies common sense only applies to things that are common to a group of people and not really open to debate.

  • “We need clean air to breathe and clean water to drink.”
  • “The pointy part goes in the enemy.”
  • “Firefly was the greatest show ever made. Seriously, like EVER!”

Common sense would dictate he’s using the right port-a-potty. See, because it’s on the right. Never mind.

The problem is all of those are open to debate. Except the Firefly one. Plenty of people will tell you clean air and water are overrated, especially where profits are concerned. There are swords that slash rather than stab. In the right collective – specifically rapiers and such – yes, the pointy part goes in the enemy, but in other collectives like scimitars, the best use is for slashing.

Almost every example you can think of where someone refers to something as common sense actually indicates a learned response to something. Even something as simple as “fire burns” had to be learned somewhere. You put your finger on the candle and – holy cow! – that doesn’t feel good. To put it bluntly, there’s no such thing as innate knowledge.

And that right there is the problem with referring to anything as common sense. In the right group, it’s just common sense that we ban all the Muslims (I don’t fall into that group, by the way). There’s not necessarily a solid rhyme or reason behind this, it just seems truthy. It ignores a huge amount of data, though.

Even some generally accepted truisms fall apart under scrutiny:

  • If you work hard you’ll be rewarded
  • You can be anything you want to be
  • Your vote counts

More often than not, hard workers are exploited by people who are better at working the system. I’m still not Batman. Tell three million people their vote counts when gerrymandering can change the results or the Electoral College can appoint a president who lost the popular vote.


Common sense says you don’t wear a bunny suit to the lake. That’s a bear suit place. Duh. No wonder you’re all alone. Loser.

All too often calling something common sense is shorthand for saying, “Why can’t you understand this? Everyone else gets it, dumb ass.” Common sense has a very narrow definition and using it outside of its intended place cheapens the argument to the point that it’s little better than slinging insults at your enemies.

To go back the lady in the Tesla talking on her phone without using Bluetooth, well, apparently the Model S had some issues connecting iPhones with Bluetooth. A software patch fixed that. The bottom line is, I assumed it was common sense to use a hands-free device – it is the law, after all – but it may not have been working at the time. It’s still not the brightest idea in the world to roll around a crowded parking lot with kids everywhere, but that’s a different debate and her experience may have taught her she was safe doing it.

The next time someone tells you something is common sense, stop and think about it for a moment. Common sense to who? And why should it be considered common sense? If it’s just bumper sticker logic, nod, smile, and do whatever you were going to do anyway.

After all, it’s just common sense.

Got any examples, bones to pick, general rants of your own? Leave ’em in the comments. I love comments and usually respond to them.