Now we will philosophise a little bit, but not about the tool itself.

In the same way that the use of a rational way for counting multiplies the mathematical capabilities of a culture (indo-arab numbering against roman), that the use of the concept of "energy" (capacity to produce work) has sped up the understanding of our surrounding world, I think that the definition of efficient units and tools can improve significantly our capacity to understand the mechanisms of the human mind. When I read pre-energy scientific publications, I get the same confusing feeling that I get reading modern psychology. I am persuaded that the confusion comes from the lack of solid concepts and tools. And I wrote this essay in an attempt to show how it is possible to define rationally a psychological tool. Maybe it will be thought useless by the people that know their dealings, but the method used to define it might be of interest to them.