- We always underestimate the number of stupid people
- The probability of a person being stupid is independent of any other characteristic of that person
- A stupid person is someone who causes damage to another person, or a group of people, without any advantage accruing to himself (or herself) — or even with some resultant self-damage
- Non-stupid people always underestimate the damaging power of stupid people. They constantly forget that at any moment, and in any circumstance, associating with stupid people invariably constitutes an expensive mistake.
- A stupid person is the most dangerous person in existence
- Stupid people don’t know they are stupid
The above has been floating around the net for a while. While it makes an interesting read I think that having a boolean criteria of labelling someone as stupid is not necessarily accurate. While there are a small number of people who are stupid, there are many more people who are good at some things and stupid when they act outside their area of expertise. There is a saying “never take investment advice from your dentist” which is apparently due to the incidence of con-artists targetting wealthy people (such as dentists) who sometimes then pass on the bad advice to their customers.
One stupid thing that I did a few years ago was to spend more effort in choosing a mobile phone than on choosing a car. I was totally happy with my mobile phone but not totally happy with my car – and the car cost a lot more… Of course the difference between pure stupidity and tactical stupidity (for want of a better term) is that a smart person who is about to do something stupid can generally be persuaded not to do it with a logical argument. If someone had pointed out to me the fact that the amount of time spent on background research for a decision should be in some way proportional to the amount of money involved (maybe proportional to the log of the value) then I would have been convinced.
So for rule 4 maybe it would be best to say taking advice from someone in an area where they are stupid is a mistake. For rules 5 and 6, if someone is known to be smart in other areas then tactical stupidity may be overlooked (until it’s too late).
Update: Don Marti commented with this link http://www.math.wisc.edu/~miller/old/incomp.txt about incompetent people being unable to judge their own level of incompetence as further evidence for point 6.