Common Sense

Through common sense, you can be convinced of anything; literally. People will manipulate you through your common sense right along with other avenues such as your needs, your vulnerabilities, your emotions, your imagination, your greed, your innate belief most people are honest, etc. Con artist rely on people being casual in their thinking.

For important matters, casual thought is the enemy of the intellect and will eventually cause you harm.

Don't rely on your common sense.
But, I'm not sugesting we abandon common sense, it is important and has its place in our thinking. If a car is about to hit you, don't calculate a statistical probability it might miss you: of course, move out of the way & do the math later. I'm saying, if it's important, get the evidence and verified facts: use reality and not substitutes such as personal bias, belief, hope, trust, affiliation, deceit, etc. Determine and confirm the genuine facts.

The Problems With Common Sense
A teacher once declared to the class we must leave our common sense at the door, that thinking people do not rely on it. Pandemonium broke out. The class has never heard such audacity, such "anti thought", such "stupidity". I'm sure the teacher was accustomed to the response so he proceeded to prove his point.

The Same Birthday
There was about 20 of us in the class when he proclaimed that he would bet two people in the room have the same birthday. Ha, we all thought, "Not likely because 20/365 seems unlikely odds". So, the class, one by one, started calling out their birthday. By the time the 7th person announced his birthday we had a match: two classmates with the same birthday! Pure luck I thought, but...

[score = "common sense" zero and facts one].

Here's what happened. The class used common sense but the teacher knew something we didn't: facts and statistics. Here's what he knew: in a room of only 22 people, the probability is better than 50% two people have the same birthday. Common sense wasn't even close and predicted highly unlikely.

The Card Trick The teacher could see we were not buying it 100%. Common sense is so very dear to the middle class and we were raised on it. So, our teacher then proceeded to do a card trick. He would flip through a deck of cards, hold one up to the class, and the class would announce the card.

On the 4th card the class in unison announced eight of spades,
The teacher said wrong.
We could "clearly" see it was the eight of spades thus pandemonium broke out again.
The teacher said, ok, let's put that card to the side & continue.

As the teacher flipped another card, in unison the class announced ten of hearts.
The teacher said wrong; we were told to closely examine the card.
  It was NOT THE ten of hearts, it was the ten of SPADES.
      but the spades were colored red!

The teacher then held up the first card we got wrong.
We examined that card. It was the eight of HEARTS, but the hearts were colored black.

The class relied on common sense instead of observation and facts.
You can literally find millions of other examples in history. Such as
Frederick Drummond placed the title to his Rolls Royce in the collection plate,
the world is flat,
the sun revolves around the earth, etc.

They seem silly today, but they too were based on common sense and they too were all wrong. I learned a lifelong lesson I continue to perfect to this day. If it's important, don't rely on your common sense.

PS: [final score that day = "common sense" zero and facts two].

Trust - Wisdom comes from managing the "risk to trust ratio"
Facts - Determine and confirm the genuine facts
Imagination - A very powerful process that affects emotion which can cause action