A few years ago, I was browsing round Foyles at lunchtime.
Next to all the books, on the wall, was a map of the world.
But something was funny about it, it was distorted.
The top part (Europe, USA, Russia) was squashed, flat and thin.
And the bottom part (Africa and South America) was stretched out, as if it was melting.
One of the Foyles staff saw me looking at it.
He said “That’s a Peter’s projection map of the world”.
I said “Why is it so distorted?”
He said “It isn’t distorted, that’s real.
The way we’re used to seeing the world is distorted.”
And he took another map from a shelf and unfolded it.
He said “This is a Mercator projection.”
I said “Yes, that’s what I’m used to, surely that’s what the world actually looks like”.
He said “Actually it doesn’t. Look at the equator line that goes around the middle of the world, where is it?”
I said “It’s about two thirds of the way down”.
He said “Exactly, if it was accurate it would be exactly halfway down wouldn’t it?”
I said “So the map I was taught in school is wrong?”
He said “Yes, they’ve been teaching the Mercator projection in schools for around 400 years.”
I said “Why would they do that?”
He said “Well, all of our history, all of our politics, everything we need to know about, it all happens in the top part of the map: the Northern hemisphere.
It wouldn’t make sense to squeeze the bit we’re interested in into just the top part, and have the entire rest of the map for the bit we’re not interested in: the Southern hemisphere.
So they stretched out the part we’re interested in, and squashed the part we’re not.
That’s why this looks wrong, we never see the world this way.”
I stood there trying to get my head round that.
This is what we call cognitive dissonance.
My rational mind (Kahneman’s type 2 thinking) is telling me the newer Peters projection is obviously right.
But my intuitive mind (Kahneman’s type 1 thinking) is telling me the older Mercator projection is right.
All my life I’d grown up knowing Africa was roughly the same size as Eastern and Western Europe put together.
But in real life, Africa is as big as Eastern and Western Europe, plus the USA and Mexico, plus India, plus China, plus Japan.
In fact, Africa and South America are each double the size I thought they were.
And I realised all we ever actually live in, is our minds.
We think there’s an independent reality out there that is the truth.
But it isn’t the truth unless it exists in our minds.
That’s how truth works. That’s how the mind works.
That’s why the Mercator projection is still being taught in schools, even though it’s wrong.
Because the wrong map is more believable than the right map.
As Churchill said “A lie can be halfway round the world before the truth has got its boots on”.
This piece first appeared on Dave Trott's Blog here