Coincidence? Extraordinary more like…


Whenever I hear the word ‘coincidence’ in my head, it’s being spoken by Stephen Moore as he reads the audiobook for Douglas Adam’s “Life, The Universe, and Everything”. Specifically, the pitiful creature Agrajag is remonstrating with our hapless hero Arthur Dent in a cave. Arthur’s defence is to keep claiming that it’s all just one big coincidence. No idea what I’m talking about? Well I urge you to read his 5-book trilogy.

During my formative years, I trained as a Physicist. One of the things you learn is that there are a lot of ‘constants’ in life – G (gravitational constant) is one of them, but there are a lot of others (the speed of light is perhaps the most famous I’d say, but Planck’s constant is well up there in many a Physics lecture). In one of my most memorable lectures (which sadly were few and far between – I tended to come in late and hide in the back with my mate Martin writing doodles on each other’s notes) I remember the lecturer explaining the following.

Lots of these constants are linked together. Here’s a (rather too pink) example:


I won’t both you with all the numbers, but let’s just tell you one. The speed of light (c) is 299792458 m/s. In other words, it’s more or less 300 million units. If you have a look at the above equation, then it’s clear that if you adjusted the speed of light, then the answer would still be the same so long as you reduced either Planck or Rydberg constants, or you increased the Gravitational constant.

  • Easy eh? Just make up a number, and then adjust the other numbers to fit. Simples.

Actually, not quite simples. It turns out that the Universe is unbelievably well balanced. If you changed one of those constants even slightly (and adjusted the others correspondingly in order to balance) you’d find that the universe just wouldn’t work. Well it would work, but not in a way that would allow any intelligent life to evolve. You would imagine that (with the values changed, let’s say gravity halved) we’d all be walking around on slightly larger planets with slightly smaller heads looking at a slightly pinker sun but (overall) not much difference eh?

Wrong. We wouldn’t be walking at all. There’d be no (intelligent) life at all. Depending on the changes, we’d all be crushed under too much pressure or boiled alive with too much heat to evolve into anything like humans.

  • No, it turns out that for intelligent life to exist, those values have to be almost precisely what they actually are.

“Wow, that’s interesting” I hear you say. You are thinking to yourselves that whoever (“God”) created the Universe deliberately chose the values so that humans could evolve. Great, that just about proves God exists right? Well, actually no – this is simply my favourite example of the anthropic principle. It is just a terrific example of coincidences.

But don’t worry, there’s still a nice space left for God to fit in. You can read all about that in my next post.


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