Why, why, why?

This was originally published here on Matters Scientific, the Cherwell science ’blog.

It is a popular and widely-known fact that there are some questions science can’t answer. For those, as we well know, we must hand over to the chaplain. He will probably flap his robes, quote from the New Testament and conclude that God moves in mysterious ways.

Enough religion-bashing. What questions exactly can’t science answer? They are commonly grouped as ‘why’ questions: physics can describe gravity, and explain how its strength varies with proximity to massive bodies, and even quantify how clocks will run at different speeds depending on gravitation, but why it exists is beyond the realm of scientific enquiry.

‘Why’ questions may sound like an intuitive set but, like all purely linguistic definitions, it’s phoney and imprecise. I had to be very careful in that last paragraph not to write that we know ‘why’ gravity’s strength varies—linguistically, it parses, and logically, we do know: it’s because mass bends space–time. In fundamental science, it is fair to say we know ‘why’ something happens if we have an accurate mathematical theory underpinning it.

What do we need for a mathematical description of a phenomenon? We need to take repeated measurements against which we can compare the theory’s predictions: the wobble in Mercury’s orbit, the bending of light by huge, distant galaxies…all data points corroborating general relativity. Crucially, to keep the Popperians happy, we must not find any credible counter-examples.

So what creates what we loosely called a ‘why’ question above? The lack of multiple instances for comparison. Say we found another universe where gravity was weaker—we would look deeper, and try to come up with a general rule which explained the difference. Perhaps other aspects of that universe would be different, and perhaps those differences would highlight an interplay between the constants of our Universe that we hadn’t already noticed. However, even this idealised hypothesising leaves open the question of ‘why’ our newer, better, more explanatory theory is true.

The reductio ad absurdum at the end of the tunnel is the most fundamental question in philosophy—why is there something rather than nothing? That is perhaps the only question science will never be able to answer. Time to hand over, not to the chaplain, but to the anthropic principle: if there weren’t something rather than nothing, we’d not be here worrying about it.

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