According to every experiment, the constants of nature appear to be constant.
And this creates a really sticky, nasty, ugly problem for us: it looks like the constants are fine-tuned. As in, if they had any other value, we’d be dead. Actually, less than dead, which is probably worse. Non-existent. Impossible to be here.
Check this out. Let’s say we change, I don’t know, the electron mass. Just a tiny bit. A few percent. Not a big deal, right? Wrong. This changes atomic energy transition levels. It changes how light is emitted and absorbed. It changes nuclear fusion rates. In a universe with higher electron mass, stars don’t form. They can’t form. No stars, no planets. No planets, no life. no life, no us.
Change the strength of gravity? Big bang doesn’t even get started. Change the dimensions of the universe? Light can’t propagate. Change ANYTHING, even a TEENSY BIT, and it all just goes…poof. The history of the universe is completely different, let alone chemistry or even biology. It’s all just gone. WE’RE gone. There is no US in a universe with different constants.
That’s…that’s a real whopper of a realization. It feels like we’re living on the knife’s edge, and if any of these numbers were to change then our universe as we know it would disappear in an instant. WE would disappear in an instant. That’s a rather uncomfortable feeling so I won’t blame you if you need to actually sleep tonight and you just pause the episode right here.
There are some potential answers, of course, none of which are all that satisfying.
The first response is called the Anthropic argument: the universe is the way it is because if it wasn’t the way it is we wouldn’t be here to observe it. That’s it. That’s the entire argument. Why is the speed of light like this and the strength of gravity like that? Because if they were different, we couldn’t exist. And if we couldn’t exist, we wouldn’t be around to observe these values of the constants.
I mean, okay. I have to admit I’m not very fond of the anthropic argument, but I’m trying to give it as far a shake as possible. Ah, who am I kidding, the argument may feel satisfying at first, but it’s like eating a whole row of cookies in one go, after a while you start to question your life choices.
It is possible to expand the anthropic argument to make it a little more flexible. You can argue that the precise value of the constants don’t matter. Sure, different combinations of constants wouldn’t give rise to OUR kind of life and OUR kind of consciousness, but maybe different combinations lead to different kinds of life. you know, the classic “life finds a way” argument. Like it may be possible to build a universe with different constants (different electron masses and whatnot) that end up with different kinds of life/intelligence that end up asking the same questions as us because they can’t possibly fathom OUR kind of life – they’re like, look we calculated what would happen if the FSC constant had this value and then all of a sudden the strong nuclear force is weaker and you get these things called STARS, which would totally be incompatible with life.
But this is pure speculation. We certainly don’t understand consciousness, let alone life, so arguing that consciousness is going to arise in ANY kind of universe is going to be a stretch.