It was about time that I brought here the Stupidity Theory of Carlo Maria Cipolla. And no matter how interesting you may find this comment, do not miss the opportunity to read his incredibly funny and very revealing book "Allegro ma non troppo" (Happy but not by too much).
Here you have Cipolla's five fundamental laws of stupidity:
1. Always and inevitably each of us underestimates the number of stupid individuals in circulation.
For Cipolla there is a fixed proportion of stupid individuals in any given population (be this a nation or any other group, as the American Association of Medical Doctors, a European Studies Class at SDSU or the Spanish Blogger Community: the percentage of stupid individuals is a constant, and always superior to the expected).
2. The probability that a given person is stupid is independent of any other characteristic possessed by that person.
This law adds up to the unpredictability of individual stupidity, for there is no clue with which to anticipate this trait.
3. A person is stupid if they cause damage to another person or group of people without experiencing personal gain, or even worse, causing damage to themselves in the process.
Here Cipolla comes up with a division of human behavior according to the check and balances of personal and social gain, classifying people in four different basic groups depending on the gains and losses that their actions produce, either to themselves or to others. With this, if the actions of someone produce personal gains while damaging others, this person would be defined as a Pillager. The further classification of Intelligent (personal gains and gains to others), Naive (personal losses and gains to others) and Stupid (personal losses and losses to others) are then easily understood.
4. Non-stupid people always underestimate the harmful potential of stupid people; they constantly forget that at any time anywhere, and in any circumstance, dealing with or associating themselves with stupid individuals invariably constitutes a costly error.
The main danger of stupid people is that while one can somehow predict the actions of a Pillager (he would always seek a personal benefit), one cannot predict in any way the actions of a Stupid guy, for he will be provoking damage to others for no reason and even if his action produces a damage to himself, and even more, no matter if the personal damage he is causing upon himself is greater than the damage he is provoking to others. As such, the underestimation of the harmful potential of stupid people, and specially the harmful potential of associating with stupid people, is a very dangerous one, for we will be suffering a damage for no imaginable reason.
And so, even though there is no clue whatsoever with which to anticipate the stupidity of anyone (no title, social status or physical trait can be used to anticipate whether anyone will be stupid), it is only their actions that can tell who is stupid, beyond reasonable doubt. And as the law implicitly states, this recognition must never be underestimated.
5. A stupid person is the most dangerous type of person there is.
A fundamental law that, even following from the precedent, can never be overestimated.
For a German translation of Cipolla's book: Amazon.com