Why Percentyl exists.
A tool born from a thesis about AI, built first for the daily use of the person who wrote it, and made public because it can be useful to others.
The thesis
Rationally, AI can indeed do everything. It is the median of human thought and human knowledge, combined with the ability to source and absorb the whole of available knowledge and give it back. On that ground the game is over, and there is no reason to regret it.
What it is not, however, is the spark of human thought. The contrarian mind.
In a decision process, the rational answer is what you should follow in the majority of cases. But there are, and there always will be, situations where contrarian thinking turns out to be right. And since AI manufactures consensus, mechanically, the contrarian edge is likely to become more and more valuable.
What needed training
Hence the conviction behind this tool: the contrarian edge has to be trained. That is, becoming a genuine critical thinker, but only when it is useful, necessary, and better than the consensus.
That last condition matters as much as the first two. Being contrarian on principle is not a skill, it is still letting the crowd decide your position and taking the inverse. What can be trained is discernment: following the consensus most of the time, at no cost, and departing from it at the precise moment it is wrong.
Why a tool rather than a book
Looking for ways to train, none turned up. There are excellent books on judgment, and they change what you know. None of them tells you whether you have improved.
That is the only thing that counts. Nothing inside us separates a sound intuition from a false one: both arrive with the same feeling of obviousness. The only remedy is external, and it comes down to four moves: write down what you think, put a number on it, date it, and let reality settle it.
So it started as a small personal solution for training every day. One real case, a probability locked before the outcome is known, a score compared with the other players rather than with an abstract truth, and a course explaining why all of it is necessary.
Who it is for
Percentyl was created for its author, who uses it daily to improve. That is worth saying, because it explains most of the choices: no advertising, no data sold, no mechanics designed to keep you longer than necessary, and a score that refuses to appear before thirty resolved cases because below that it would only measure noise.
If it can be useful to others, making it more widely available is a pleasure. That is the only ambition behind publishing it.
Who writes
Quentin Devillechabrolle, formerly of Palantir, where he spent years steeped in contrarian thinking, alongside the people who practise it best in the world, and daily.
The simplest way
One real case, today.
The thesis above is worth nothing until it is tested on you. Today's case can be played without an account, and your score appears after thirty resolved cases.