People often use the term common sense in ethical and logical contexts when it comes to real-life situations. I once had a (clever) boss who questioned my work based on common sense. “Common sense says that you should not have done it that way…”, he criticized.

Yet, neither did I understand what exactly he meant, nor was I convinced about the notion of common sense in the first place. Merriam-Webster defines common sense as follows:

“…sound and prudent judgment based on a simple perception of the situation or facts.”

— Merriam-Webster

I once heard a driver scream, “Don’t you have any common sense?!” at a fellow motorist who had caused an accident. When you consider Merriam-Webster’s definition in the context of such situations, it does seem to make sense.

Yet, here I am to argue that not only is common sense not common, but it does not even exist, to begin with. To start understanding the issue, let us start with “sense.”

This essay is supported by Generatebg

A product with a beautiful background featuring the sponsor: Generatebg - a service that generates high-resolution backgrounds in just one click. The description says "No more costly photographers" and displays a "Get Started" button beneath the description.

What is “Sense”?

The word “sense” can mean many things. In the context of common sense though, let’s turn once again to Merriam-Webster to see which meanings are most relevant:

“1. A meaning conveyed or intended…

2. The faculty of perceiving by means of sense organs.

3. Conscious awareness or rationality.”

– Merriam-Webster.

If you already feel overwhelmed by the various meanings that the word “sense” can have, I don’t blame you. Our problem starts there. But for the sake of understanding the issue deeper, let us assume that sense means “judgement based on simple perception by means of sense organs.”

If you think about it, given the context of the term “common sense”, this assumption is not a bad one at all. Now that we have a lock on what sense means to us, let us proceed to what “common” means.

What is “Common”?

The word “common” is far easier than sense, as it does not have as many contextual meanings. When you and I share a property, we could say that we have a common property. It could be material properties like “blonde hair”, “red mustache”, etc., or immaterial properties like “music preferences”, “topics of interest”, etc.

We could go into more detail, but you get the picture. In the context of common sense, if people share a “sense”, we could say that it is common sense. But an ambiguity arises when we ask the following question:

“Should this sense be shared by EVERYONE? Or does a majority suffice for it to be deemed common sense?”

The pursuit of an answer to this question leads us to the next part of the discussion.

Common Sense is Not Really Common

Think of the last time you and your friends discussed a trendy hot topic in a gathering (like wearing medical masks, for instance). Did all of you share a single moral opinion on the topic or did you have divided opinions?

The latter is far more likely than the former. And these are your friends we are talking about here. If anybody, you and your friends are the most likely folks to have stuff in common. And yet, even amongst friends, there seem to be divided opinions when it comes to day-to-day topics.

The reason for this is simply “the subjective nature of life.” Even though I and my best friend have many things in common, we make sense of our real-life experiences subjectively based on various factors.

For instance, based upon my upbringing, I might favour one ideology whereas my best friend might favour another one. And that’s where the answer to our original question becomes tricky.

“Should the sense be shared by EVERYONE? Or does a majority suffice for it to be deemed common sense?”

It is clear by this point that commonalities shared by “everyone” are highly unlikely. So, if we agree that a majority suffices for common sense, then the next question is “which majority?”

Common Sense Does Not Even Exist!

Let us say that I have a preferred ideology about how drivers should behave in traffic. Since I am a human being, I am likely to pay more attention to other drivers who share my ideology. This introduces a hidden bias in my mind which tricks me into thinking that my ideology is shared by the majority.

When an accident happens, lo and behold, I am likely to question the “common sense” of my fellow motorist who caused the accident. I think that it is common sense to everyone, whereas the reality is otherwise.

Common Sense Is Not Really Common At All — A serious-looking stick figure with glasses is seated on a chair on the left. It seems to be taking notes using a pen in a notebook. On the right, is another stick figure lying down on a couch. To their right, there is a classy standing lamp. The seated stick figure asks “This common sense…Is it in the room with us right now?”
Common sense cartoon — Illustrative art created by the author

The only things common about “common sense” are those two English words. Underneath them, each and every person likely has a subjectively different understanding of what it means. Let’s go back to Merriam Webster’s definition of common sense:

“…sound and prudent judgment based on a simple perception of the situation or facts.”

What does “sound” or “prudent” judgement mean here? Or what about “simple perception”? As you can clearly see, these adjectives have a lot of room for interpretation. All this leads to the blatant case that “common sense” does not even exist.

To understand the mathematics behind this phenomenon, check out my essay how polls mislead most of the time.

So, if common sense does not exist, why do we use still use the term?

What is Common Sense, Really?

In reality, common sense is not even a sense; it is an ideological fallacy. The word “fallacy” is a technical word, and we have to be very careful when we are dealing with it. I have covered this topic in a dedicated essay. If you are interested, check it out.

For now, let us just say that “common sense” is a term that people use to express their ideological belief, thinking of it as common rational sense. Think about it; I might share an ideology with my friends, but it might not be shared by the rest of the world. Similarly, an entire city might share an ideology, while the rest of the world doesn’t.

We can keep going. Some ideology might exist as “common sense” for an entire country, while the rest of the world is oblivious to the thought. In even larger scales, some ideology might pass as “common sense” for an entire religion, while other religions might not share the ideology.

We could conveniently choose our sample size to make any ideology “common”, and call it a “sense”. In short, “common sense” is an intellectual trap.

If it indeed existed, conflicts and disagreements among us would be far less frequent than in our current reality. Now that I have covered why common sense is a trap, let’s see how you can protect yourself from falling for it.

How to Avoid the Trap

Apart from the awareness that common sense is a myth, there are two tools that I would suggest for avoiding the trap of common sense:

1. Critical thinking: Ask curious questions at the most fundamental level with the willingness to understand what is going on, instead of presupposing a hypothesis.

2. A hypothesis is not always avoidable. So, if you are indeed working with a hypothesis, make sure that you are open minded by formulating alternative hypotheses. Being open-minded means that you are open to the possibility of your hypothesis being false; this does not come to us human beings naturally.

You might think that clever people are unlikely to fall into the trap of common sense. Remember the short story about how my boss criticized me from the beginning of this essay?

Well, he is one of the cleverest people I have ever worked with. The bottom line is that all human beings are likely to fall prey to the trap of common sense. So, be warned!

If you’d like to get notified when interesting content gets published here, consider subscribing.

Further reading that might interest you:

If you would like to support me as an author, consider contributing on Patreon.

Street Science

Explore humanity's most curious questions!

Sign up to receive more of our awesome content in your inbox!

Select your update frequency:

We don’t spam! Read our privacy policy for more info.