Because the universe is beautiful enough without having to lie about it

Rules for rational thinking

June 29th, 2008 Posted in General

Can rational thinking be condensed to a few simple rules that are easy to apply in any circumstance?  I think so.  At very least it’s possible to look at examples of bad thinking and work out why they are wrong.  I think I’ve come up with a pretty good list of the most important ones, and I’ll condense them down further when I get time.

  1. People lie.  (Also called “House’s Law”, after the eponymous TV series). And not only do people lie, but they also mislead (intentionally or otherwise).  I was always brought up to believe that it’s good to tell the truth, and also that good people succeed in life whereas bad people don’t. So when I see someone successful on TV I suppose it’s tempting to assume that they’re truthful. But, of course, that’s not always the case. In fact, being dishonest is a very good way to earn a lot of money.
  2. Incomplete information is often worse than ignorance.  It’s possible to prove almost anything without lying, just by dealing with only a small selection of the data.  For example, if I wanted to prove to visiting aliens with no knowledge of sports, that my local football team was the best in the world, I could just show their wins, and not show their losses.  Similarly, if I wanted to convince people of a fringe scientific belief, I could show a dozen PhD scientists claiming such a theory to be true, and ignore the hundred thousand other PhDs who disagree.
  3. Intuition is unreliable.   We evolved to cope with siuations that our ancestors regularly encountered in their everyday lives. Simple situations, with medium-sized numbers. We’re very bad at coping with big numbers (or, indeed, microscopically small ones).  The human brain simply can’t imagine, with any reliability, what happens in timescales of billions of years, or over distances of millions of light years, or at scales of the size of an electron, or time intervals in picoseconds.  We know that there are about a hundred million stars in the Milky Way galaxy, but we don’t really appreciate what that means. We can take the number and do maths with it, but that’s not the same thing.  So when people are dealing with very large or microscopic quantities and say something is “obviously” false, what they mean is that it feels false using intuition.  Get them to prove it. That’s why science was invented – because intuition isn’t enough.
  4. All conspiracy theories are wrong. Conspiracy theories always rely on very large numbers of conspirators all going along with a gigantic lie, keeping their silence until death without a single one of them, under any circumstances, revealing the truth.  We know, from human nature, that this is never going to happen.  Please, don’t credit your government with more intelligence (or power) than they deserve. When they can actually make the trains run on time then I’ll rethink this one.
  5. Implication works both ways. This is a subtle one, but incredibly important.  It should probably be nearer the top.  When a theory seems to fit in with a few observations, ask “what else does this theory imply?” For example, the age of the oldest trees on Earth are younger than 6,000 years, and so is human civilisation (roughly). These seem to agree with a very young Earth.  But what else would that theory imply? Well, for a start, it would imply that nothing on Earth could be older than 6,000 years, which we know to be false from innumerable sources.

There are some other rules for logical arguments on my evolution page at  At some point in the future I think I’ll condense these down to the 10 Commandments of Rationality.  If anyone wants to help then drop me a line.

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