The magic which makes the speed of light what it is

Through the process of science we have discovered a great many “natural” constants that apply to our reality. These include  the speed of light in vacuum c, the gravitational constant G, Planck’s constant h, the electric constant ε0, and the elementary charge e. But why these constants are what they are – and not greater or smaller – still escapes us.

Physicists do not like to be contaminated by magic, but they do in fact invoke magic every time they use any of these so-called natural constants. That they are constant over time is itself an assumption without rhyme or reason as to why they should be so. That the passage of time is regular is itself a magical assumption. That a second now is of the same duration as a second 9 billion years ago or of the same duration as a second 10 billion years from now or at the other end of our universe are all just magical assumptions.

And so it is with the speed of light.

We have now fixed the speed of light in a vacuum at exactly 299,792.458 kilometres per second. Why this particular speed and not something else? Or, to put it another way, where does the speed of light come from?

……. Whether it was the ‘hand of God’ or some truly fundamental physical process that formed the constants, it is their apparent arbitrariness that drives physicists mad. Why these numbers? Couldn’t they have been different?  ……. leads us to the anthropic principle, the philosophical idea that what we observe in the Universe must be compatible with the fact that we humans are here to observe it. 

…… Why should the multiverse work like this, and not that? Perhaps it isn’t possible for the intellect to overcome a sense of the arbitrariness of things. We are close here to the old philosophical riddle, of why there is something rather than nothing. That’s a mystery into which perhaps no light can penetrate.

We don’t know why the speed of light is what it is. We don’t know what would have to be different in our universe for this speed to be different. We do not know if this value was always what it is now and will always be so. We don’t know if there are regions in our universe where it does not apply. It is what it is by magic.

I take the view that to the finite human mind some things are unknowable.

And as long as the unknowable exists in physics, physics must take recourse to magic. Giving magic a name or a label does not reduce its magicality.




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