Understand that thinking works in two modes (fast and slow), and why the fast mode is the source of most errors.
Why this course
A trained eye for traps, not theory
This course is a trainer. The goal isn't to cram clever terms but to learn to NOTICE thinking traps in real life: in an argument, in an ad, in the news, in your own head.
The brain is a brilliant machine, but it cuts corners all the time. These shortcuts save energy and once saved lives in the wild, but in the modern world they systematically fool us. The good news: thinking errors aren't random. They repeat in the same patterns. And that means you can learn to recognize them.
Just as a detective recognizes a criminal's signature, you'll learn to recognize the signature of biases and logical fallacies. First in other people's examples, then in any situation.
The main technique of the whole course is simple: if you notice that a conclusion came on its own, instantly and with total confidence — be on your guard. That's exactly where the trap is most often hidden.
Lesson notes
A trained eye for traps, not theory
This course is a trainer. The goal isn't to cram clever terms but to learn to NOTICE thinking traps in real life: in an argument, in an ad, in the news, in your own head.
The brain is a brilliant machine, but it cuts corners all the time. These shortcuts save energy and once saved lives in the wild, but in the modern world they systematically fool us. The good news: thinking errors aren't random. They repeat in the same patterns. And that means you can learn to recognize them.
Just as a detective recognizes a criminal's signature, you'll learn to recognize the signature of biases and logical fallacies. First in other people's examples, then in any situation.
The main technique of the whole course is simple: if you notice that a conclusion came on its own, instantly and with total confidence — be on your guard. That's exactly where the trap is most often hidden.
Fast and slow
The psychologist Daniel Kahneman (winner of the 2002 Nobel Prize in economics) described two notional systems of thinking in his book “Thinking, Fast and Slow”.
— System 1 is fast, automatic, effortless. It's what instantly understands that 2 + 2 = 4, recognizes a friend's face, senses anger in a voice, drives a car down an empty road. It runs on intuition, emotions, and habits. It almost never rests.
— System 2 is slow, deliberate, effortful, and demands attention. It's what calculates 17 × 24, fills out a tax return, thinks through a complex argument. It's lazy and switches on reluctantly: real thinking is hard and draining.
Important: this is a metaphor, not two “departments” in the brain. But it's a very handy metaphor. Most thinking errors happen like this: a task that System 2 should handle is quietly taken over by System 1 — which produces a fast, confident, but wrong answer.
The classic test for this is the bat-and-ball problem (you'll solve it right now).
Breaking down the ball problem
Most people instantly answer “10 cents” — that's System 1's hint: $1.10 splits by itself into “$1” and “10 cents”.
But let's check. If the ball costs 10 cents and the bat costs a dollar more, the bat costs $1.10, and together they cost $1.20. That doesn't add up.
The right answer: the ball is 5 cents, the bat is $1.05 (a dollar more), together $1.10. That adds up.
Students at the world's top universities have taken this test — and more than half gave the wrong answer, “10 cents”. It's not about math ability (the arithmetic here is elementary) but about System 2 being too lazy to switch on and trusting the fast answer.
The takeaway: the feeling that “the answer is obvious” is no proof that it's right. Often it's a sign that you haven't even started thinking.