Humans don't think especially well, not naturally. You have to be taught to think, and there aren't very many classes in how to think. That's supposed to be the point of basic science classes and of Plane Geometry under the math curriculum, but there's so much material that needs to get covered there that the "how to think" stuff gets crammed into maybe three one-hour classes in the course of an entire 12-year education. That's not enough. The biggest reason that this isn't enough is that there are a lot of things that humans mistake for thinking, but they're really not. There's a lovely list up on Wikipedia of logical fallacies. If you did nothing more than bookmark that web page and once per day read the next entry in line, you'd become noticeably, perceptibly smarter with each and every one, because you'd be weeding out of your brain the broken logic that substitutes for thinking so many times. But there's one missing, and it's the one that bugs me the most: single-valued logic. If I could wave a magic wand and get rid of one form of species-wide human stupidity, it would be single-valued logic.

In single-valued logic, every phenomenon (let's call it x) is reduced to a single value:

• If x is good, then a tiny amount of it is good, more is better, the most of it makes you the best, and there is no such thing as too much.
  
• If x is bad, then the less of it the better, and any amount of it is bad, and only zero is acceptable.

In single-valued logic, how do you decide whether something is good or bad?

• If too much of x is bad, then it means that x is always bad, and it must be eliminated.
• If there is any amount of x that is good, then it means that x is always good, the obvious thing to do is to get as much x as possible, with no limit.

A few samples, as applied to politics:

• If there is any tax that is bad for the economy, then taxes are bad, and all taxes are bad, and less taxes are always better than more taxes, and the only acceptable amount of taxes is zero.
  
• If there is anyone who's ever gotten any good out of religion, then religion is good, and religion is good for everybody, and more religion is better, and the ideal society is one in which religion is in 100% total control.
  
• If money is good for anything, then money is good, and more money is always better than less money, and therefore the person with the most money is the best person.
  
• If having an army that can protect your country is good, then the military is good, and therefore all of the military are good, and the more military the better, and the perfect society is one in which the military has total power.
  
• If there is such a thing as a drug overdose, then drugs are bad, and all drugs are bad, and any amount of any drug is bad, and the only acceptable legal policy is zero drugs.
  
  
• If there is anyone who's ever been helped by a social worker, then social workers are good, and therefore all social workers are good, and therefore the only right number of social workers is when everybody has one.
  
• If any war is bad, then all war is bad, under every circumstance, and never is war anything but bad.
  
• If any religious person has ever done anything bad, then religion is bad, and less religion is always better than more religion, and the only acceptable amount of religious influence over society is none.
  
• If any corporation is bad, then it means that corporations are bad, and therefore all corporations are bad.
  
• If there is such a thing as good sex, then it means that sex is good, and therefore sex is always good, and more sex is always better than less sex, and therefore the only good society is one in which sex is all-important and everywhere.

Those are only examples. You can apply single-valued logic to anything.

• If your home town is good, then everything in it has to be good, and you never want to hear anything bad about it.
  
• If your home town is bad, then everything about it must be bad, and you never believe anything good about it.
  
• If Windows works for anything, if it's ever the right software solution, then it's the only "right" operating system, and Linux and MacOS are bad.
  
• If Linux is a better solution than Windows at anything, then Linux is good, and therefore good for everything, and everybody must replace Windows and MacOS with Linux.
  
• If smoking has ever hurt anyone, then smoking is bad, and all smoking is bad, and less smoke is always better than no smoke, and no amount of smoking is acceptable, and the only acceptable society is one in which nobody smokes.
  
• If vitamin C is needed to ward off scurvy, then vitamin C is good, and therefore more vitamin C is always better than less vitamin C, and the ideal amount of vitamin C is the biggest mega-dose you can afford and/or choke down.
  
• If any carbohydrates can be empty calories in your diet and make you fat, then carbohydrates are bad, and less carbs are always better than more carbs, and the ideal diet is one with zero carbs. If fat in your diet makes you feel full and eat less, then fat is good, and more fat in your diet is always better than less fat, so eat all the fatty foods you can choke down.
  
• The classic dry alcoholic's fallacy, the prohibitionist fallacy: if alcohol has ever lead to spousal abuse or date rape, then alcohol is bad, and therefore any amount of alcohol is bad for everybody, and less alcohol is always better than more alcohol, and the only acceptable amount of alcohol in a society is zero.

Any time you catch yourself thinking like this, knock it off. Single-valued logic is a natural need of a not-very-bright prey species. If you hesitate to decide whether or not something is really bad this time, then the bad thing may catch you and eat you while you're making up your mind. If you hesitate to decide whether or not even more of the good thing in front of you is still good right now, somebody else will snatch yours up and you won't get any. Well, you're not a deer. You're a human being. Learn to think.