Suppose someone is rolling a set of two dice. He rolls a double six – something with a one in 36 chance of happening. Which is more likely, that the person rolled a set of regular dice and just got lucky, or that he rolled a special set where both dice have just sixes on all faces? (Let’s assume you can’t see any but the sides that are on the top.) You might think that since a regular set would produce a double six in only one out of 36 attempts, he is more likely to have rolled the trick dice with just sixes. But after a moment’s thought you would probably realize that was wrong. With just one roll of the dice, you would have no way of knowing. The person might have been rolling the dice all day, and you just happened to come along at the exact time that he rolled the double six. Of course, you could stay and see if he rolled the dice again, and if he kept getting double sixes then you would suspect there was something fishy going on. But with just one roll, there is no way you could tell. You wouldn’t have enough information.
The same would be true if the guy rolled three dice and got three sixes, or four dice and got four sixes, or five dice… etc etc. If he only called you over to look when he’d got all sixes, you wouldn’t know if his roll had been especially lucky, or if he had spent hours rolling other combinations, and only called you to look when the result was all sixes. No matter how many dice he rolled at once, or how high the apparent odds against it happening by chance, you wouldn’t know he was cheating just by looking at the result of one roll. You also wouldn’t know how many other people are rolling dice at the same time, but who are keeping quiet about it because they rolled uninteresting combinations. At the very least, you would need to see a few consecutive rolls from this one guy before you could form any conclusions.
It seems to me that fine tuning arguments are similar to the dice rolling guy. The fine tuning argument is this: the odds of “rolling the dice” to get, by chance, a universe where life can exist, are so low that the universe must have been designed. But the objections to this are the same as with the dice rolling guy: unless we know how many universes there are, and how many big bangs there have been, we can’t know if our particular universe is very unlikely to have occurred by chance or not. There might be millions of universes. And if there are a very large number of universes, then the odds of getting one tuned for life, are very good. And in that case, there are good odds that in at least one of the universes tuned for life, there evolved intelligent people like us who remark that this universe looks fine tuned for life.
Now, you may say, we don’t have proof that additional universes exist, or that there have been several big bangs. And I say that’s not my problem, it’s the problem of those making the fine tuning argument. If fine tuners are claiming that the odds of getting a universe suitable for life are extremely low, then it’s up to them to show that this is the only universe that exists or has ever existed. Their calculations that show the incredibly low probabilities of a universe suitable for life, assume there is and has only ever been one universe. Why is this? Because to get the probability of getting any universe tuned for life, they have to multiply their probability of getting one universe tuned for life by the total number of universes. They never do this – which means they are implicitly multiplying by one universe. So, before we accept their claim, they first have to demonstrate that there really is only one universe. It’s their claim, remember? They have to justify all parts of it, not just the bits they like. So as part of their own calculation, they must demonstrate that there is only one universe. As far as I know, no one has ever done this.
I have heard some say that multiple universes violate Occam’s Razor – one universe is “simpler,” they say. But this argument misinterprets Occam’s Razor. Occam’s Razor doesn’t say choose the simplest – if it did then “Goddidit” would be the answer to anything, because Goddidit is simple. Occam’s Razor actually says don’t make up unnecessary assumptions. We know that universes exist because we live in one. Unless there is a solid reason to think that there are no other universes apart from the one we see, it would be an additional assumption to insist without evidence that this is the only one. To be most generous to fine tuners, the best they can claim is that the assumption of many universes is an equal assumption to the claim that there can only be one, and so Occam’s Razor is a wash – you can’t use it to choose one way or the other. The burden of proof is therefore still upon the ones making the fine tuning claim.
Of course, we don’t need multiple universes to reject fine tuning arguments. We don’t actually know enough to be able to calculate meaningful probabilities of getting, by chance, the so-called fine tuned constants of this universe. We can only examine one universe, and can’t really say for sure what would happen if the conditions were different. Fine tuning arguments are really just god of the gaps arguments – we don’t know why the constants look fine tuned, so we’re going to use god to explain the gap in our knowledge. Never a very productive way of trying to learn the truth about anything. Also, we don’t know what kind of life would have evolved if the universe was very different from this one. Life as we know it might not exist, but that wouldn’t mean that completely different life forms couldn’t evolve. Again fine tuning arguments say more about the lack of imagination in the people making the arguments than about the truth of the conclusions they are claiming.
But even if we ignore these flaws, the burden of proof is still with the fine tuners to demonstrate that this is the only universe that exists or has even existed (or at least, that there is only a small number). Until they do this, fine tuners are like the person pointing to the guy who just told you he rolled several dice and got all sixes, while failing to investigate all the other people in the world and throughout history, who have rolled dice but didn’t tell you the results.
Physicist Victor Stenger has many other arguments against fine tuning, including simulated universes with very different values for the so-called “fine tuning” constants. He also states that multiverses are suggested by modern cosmological models.
Chaotic Inflation, proposed by physicist Andrei Linde, models our universe as one of many that grew as part of a multiverse… – he hypothesizes that the expanding cloud of billions of galaxies that we call the big bang may be just one fragment of a much larger universe in which big bangs go off all the time, each one with different values for the fundamental constants.
Note: this post was initially inspired by this comment by regular commenter AvalonXQ.