Are We Alone? Fine-Tuning the Universe, with Barnes, Keating, and Richards

Whenever the topic of the so-called "fine tuning" of the universe comes up I brace myself to hear what I think are poorly reasoned arguments leading to metaphysical destinations. Including Dr. Keating helped, I think, to provide the balance that may have discouraged that particular detour. Kudos for having a diversity of viewpoints on the show.

It's perfectly okay to use the matter of the universe's apparent fine-tuning as a jumping off point for speculation as to why it might be the way it is: that's fun, and may even, someday, be productive. But there's at least one obvious and thus-far irrefutable explanation that would render such apparent fine-tuning unremarkable: that, for all we know, universes do what ours appears to have done -- spring into being -- all the time. After all, we know nothing about the context in which our universe began (if it began), nor about the processes that precipitated it. The only reason we have to believe that ours is the only one that began in that manner is the same reason our ancestors had for believing that Earth is the only planet. Given that, drawing any large conclusions from the apparent fine-tuning is probably imprudent.

This was an ambitious program. Topics don't get much bigger than these.

Excellent post and discussion. However, the number of fine-tuning factors identified for the existence of life on Earth is at least an order of magnitude more than the 31 Luke Barnes mentions. Was he limiting himself to the cosmologcial fine tuning factors on a large scale? I suppose I must read his book to find out.

And no, Henry. There is no multiverse. Universes don't appear all the time. There is zero evidence of this, only bad interpretations of quantum theory. Furthermore, if there were a multiverse, it would only make the fine tuning problem worse, not resolve it.

Hartmann von Aue (View Comment):

And no, Henry. There is no multiverse. Universes don’t appear all the time. There is zero evidence of this, only bad interpretations of quantum theory. Furthermore, if there were a multiverse, it would only make the fine tuning problem worse, not resolve it.

First, I'm not talking about the stuff Sean Carroll et al talk about with their endless quantum bifurcation. That's what most people hear when they hear "multiverse," which is why I didn't use the phrase.

Secondly, you don't know what, if anything, existed before our universe came into being -- if it actually came into being. You don't know what the pre-universe was like prior to the start of the expansion of the universe we have. You don't know why or how our universe came into being -- again, if it came into being.

No one knows. We have no evidence of anything earlier than ~13.7 billion years ago; we have no evidence that would support or contradict the idea that the universe simply popped into existence in some context that predated space, time, and matter.

That's why I said it is "thus-far irrefutable." It remains a conceptually simple, seemingly plausible, untested explanation.

Thirdly, no, it needn't make the fine-tuning problem worse (accepting for the sake of discussion that there is a "fine-tuning problem"). If all those endless universes inflating randomly out of nothing[?] differ from one another, if their laws and/or constants can vary, then it stands to reason that the only universes containing intelligences pondering the fine-tuning of their own universes will be those compatible with life.

I'm not saying that that is the explanation. I'm just saying that you can't, that no one can, refute it.

Here's an interesting thing. The interview touched on two topics that seem intuitively improbable and suggestive of... well, of something unnatural or paradoxical.

One is the oft-discussed "fine-tuning," the seemingly nearly-impossible exactitude with which some natural constants match the apparently arbitrary values which we think they would have to have in order for us to exist. The other is the so-called "Fermi paradox," the idea that, given the vastness of the universe and the incomprehensible number of stars and planets, many undoubtedly like our own, it's extraordinary bordering on miraculous that we've yet found no evidence of life anywhere other than here on good old terra firma.

While both of these seem intuitively to be remarkable, they're actually example of reasoning from mathematical ignorance in two slightly different but complementary ways.

In the case of the fine-tuning problem, we're faced with what appears to be an extremely low-probability event, and we marvel that it occurred.

In the case of the Fermi paradox, we're faced with what appears to be an extremely large number of opportunities for an event to occur, and marvel that we see only a single occurrence.

But here's the thing. The expected number of occurrences of any particular chance outcome can be calculated as the probability, the likelihood, of that outcome occurring times the number of opportunities, or tries, we have for reaching that outcome.

The likelihood of the universe being "fine-tuned" the way it appears to be seems very, very small. But we don't have any idea how many opportunities there have been for such a universe to arise. If the latter number is very, very large, then it really isn't surprising that we live in such a universe.

Similarly, regarding the Fermi paradox, the number of opportunities for life to form in the universe seems very, very large. But we don't have any idea how likely it is for life to form, or for life to become intelligent. If that probability is very, very small, then, again, it really isn't surprising that we haven't seen any more of it.

In both cases we're letting one stunningly small (tuning) or large (Fermi) number overwhelm our senses, despite having absolutely no basis for estimating the magnitude of the other critical term in the equation.

It is a quite natural, intuitive/emotional response to an extreme number. It's the product of the same impulse that causes otherwise prudent people to buy lottery tickets when the payoff becomes numbingly large -- despite the possibility that skyrocketing ticket sales have actually depressed their mathematically expected return.

Henry Racette (View Comment):

The likelihood of the universe being “fine-tuned” the way it appears to be seems very, very small. But we don’t have any idea how many opportunities there have been for such a universe to arise. If the latter number is very, very large, then it really isn’t surprising that we live in such a universe.

And, of course, we wouldn't BE alive in any universe that DIDN'T.

Henry Racette (View Comment):

Similarly, regarding the Fermi paradox, the number of opportunities for life to form in the universe seems very, very large. But we don’t have any idea how likely it is for life to form, or for life to become intelligent. If that probability is very, very small, then, again, it really isn’t surprising that we haven’t seen any more of it.

In both cases we’re letting one stunningly small (tuning) or large (Fermi) number overwhelm our senses, despite having absolutely no basis for estimating the magnitude of the other critical term in the equation.

It's not just the initial likelihood, either. While not specifically mentioned in your comment, the time overlap must be considered. Even if millions of civilizations were formed in the universe over billions of years, the combinations of how far they would be from us, and the likelihood that we would be in a position to - for example - receive signals from them during the relatively brief span of OUR world civilization, is still small.

A civilization even relatively nearby - say, 1,000 light-years - might have risen, sent out all their radio and TV shows etc, and then fallen, before we were able to receive such signals. Or, if they're 2,000 light-years away and sent their signals 1,000 years ago, we may be gone before their signals get here. And even if we were still around then, THEY might have already disappeared. Either way, we would be unable to communicate with them, or travel to them...

Henry Racette (View Comment):

It is a quite natural, intuitive/emotional response to an extreme number. It’s the product of the same impulse that causes otherwise prudent people to buy lottery tickets when the payoff becomes numbingly large — despite the possibility that skyrocketing ticket sales have actually depressed their mathematically expected return.

To be clear, the number of ticket buyers doesn't change the odds of any one person winning, but it does affect how much they would win IF they won. Because of the increased likelihood that they would share the prize.

But I don't think the prospect of having to divide possibly over $1 Billion among even 100 people, if there were that many winners, would deter many people from spending $1 or $10 on a ticket. That's still $10 Million each for the winners. People don't buy a ticket in a $1 Billion lottery just because they expect to be the only big winner.