A fine-tuned universe without a fine tuner

Physicists are no better than their biologist cousins. The universe has parameters that are just exactly right. If they were even slightly different, nothing would hang together and human life could never exist. So rather than thinking that the universe may have had something like us in mind, some kind of end project of which we are one part, the alternative now beckons. In this multiverse, everything is random chance but with an almost infinite number of universes one of them was bound to have parameters that would allow human life to emerge. Just chance, not purpose.

So that is the story found in the latest Scientific American. In an article titled, “New Physics Complications Lend Support to Multiverse Hypothesis” here we find the problem set out:

With the discovery of only one particle, the LHC experiments deepened a profound problem in physics that had been brewing for decades. Modern equations seem to capture reality with breathtaking accuracy, correctly predicting the values of many constants of nature and the existence of particles like the Higgs. Yet a few constants — including the mass of the Higgs boson — are exponentially different from what these trusted laws indicate they should be, in ways that would rule out any chance of life, unless the universe is shaped by inexplicable fine-tunings and cancellations.

Yes, inexplicable and just so to the ten-thousandth decimal point and there are many of them just like that. What to do, what to do? How can this be explained without an outside agency?

Physicists reason that if the universe is unnatural, with extremely unlikely fundamental constants that make life possible, then an enormous number of universes must exist for our improbable case to have been realized. Otherwise, why should we be so lucky? Unnaturalness would give a huge lift to the multiverse hypothesis, which holds that our universe is one bubble in an infinite and inaccessible foam. According to a popular but polarizing framework called string theory, the number of possible types of universes that can bubble up in a multiverse is around 10^500. In a few of them, chance cancellations would produce the strange constants we observe.

That’s it. There must be 10^500 universes all different but each on its own so that one or two might have just exactly the right physical constants for life to exist. That is so much more plausible. And I especially like this:

The energy built into the vacuum of space (known as vacuum energy, dark energy or the cosmological constant) is a baffling trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion times smaller than what is calculated to be its natural, albeit self-destructive, value. No theory exists about what could naturally fix this gargantuan disparity. But it’s clear that the cosmological constant has to be enormously fine-tuned to prevent the universe from rapidly exploding or collapsing to a point. It has to be fine-tuned in order for life to have a chance.

A fine-tuned universe without a fine tuner. Our existence is therefore a probability of one in 10^500, obviously much more likely than the existence of some entity to set it all in place.

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