Why do humans reason massively wrong?

1. Because they confuse reasoning with rhetoric.
2. Because their reasoning is most often constructed backwards.
2. Because they constantly apply heuristics, or worse, dogmas.

What is rhetoric?

It's the art of gaining the upper hand in a verbal contest.

What is backwards reasoning?

In correct reasoning, one conducts an exhaustive analysis of the situation, which eventually brings to light a conclusion that one discovers.
In backward reasoning, we start from a conclusion chosen arbitrarily, because it is in accordance with our immediate interest, or our beliefs, and we build a posteriori a biased reasoning which consists in selecting and articulating the elements which justify this conclusion.

What is a heuristic?

A heuristic is a method that makes it possible to find a solution that is not too bad, to a complicated problem, with much less effort than would be required to find the optimum solution.

Take, for example, the traveling salesman problem. A very simple heuristic could for example consist of going from town to town, each time choosing the least distant one among the remaining towns. Our traveler will therefore be able to apply a second heuristic which consists of going back to the last cities, and deciding to travel through them earlier, each time making a detour as short as possible in his journey.

In our life, we constantly apply heuristics.

The interest of heuristics is twofold for the individual:
1. They make it possible to save the effort of reasoning, therefore to preserve one's time.
2. By using dogmas as heuristics, one generally improves one's position in the game of alliances.


Refer to the question 'What is a human?'

Refer to chapter 4 of the book From capital to reason.

Wikipedia article regarding cognitive biases


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