Don Page - What Does a Fine-Tuned Universe Mean？

Don, a fine-tuned universe is one of those probes that immediately elicits passion from almost anyone who understands what the term means. I want to ask you, as a physicist and as a believer, how do you look upon the fine-tuning of the universe? First question, do you think the universe is fine-tuned? Some people disagree. Well, I certainly think that what we can observe about the universe, a part of the universe that we can't observe, does have some remarkable fine-tunings. We do see that some of the constants could not be much different for us to be here. One of the most remarkable ones is the so-called cosmological constant that governs how fast the universe is accelerating, is very small. It's about 120 orders of magnitude smaller than you might have naively expected. So like a decimal point and 120 or maybe 122 zeros and then a one. And to be that close to zero, all sorts of things cancelling out and not being zero cries out for explanation, obviously. Right, yes, it cries out for explanation and there are a number of tentative explanations. One of them is that it's just a pure fluke, that it's just chance. Another one is that these constants were chosen by God to permit life in our world. And another one is that there is a multiverse of many different possible values for these and that the range includes values that do permit life to exist. So certainly the fluke or the brute fact would be shocking because it would be a brute fact. To be a brute fact by itself is okay, but a brute fact that results in our life and sentient life emerging in our consciousness today, I mean, that just seems like a brute fact too far. Yes, I think the brute fact interpretation is, you know, I think not many people would believe that. They would want to have some explanation. Some people might think, well, it just comes out of the mathematics somehow. But even then, it might seem to be like a brute fact about the mathematics, although there can be, of course. What's in mathematics is just logically determined. So if you understand it, then you're no longer surprised. But it would seem to be surprising if that were the explanation part, because it's so remarkable a coincidence. Okay, so you've got two left if we eliminate that. You have multiple worlds where you have different selections within the range that we find, or you have a fine tuner of some kind. Is it, you know, God or it could be a simulation and, you know, somebody else can be doing fine tuning. Can you distinguish between those or it just becomes a matter of faith or science? Well, I think you could say, I mean, you could have either one of them or you could have a combination. Now, I do take in some sense a combination, but I think that God structured the laws, the basic laws, maybe not including the constants, but the basic laws in such a form that it does produce a multiverse such that in the different parts, you do have sort of local laws that do have constants, and some of them do have constants that are pertaining to life. So I do believe that there's enormous design to the universe and the laws. But to my mind, I think the most elegant way God might have designed the laws is such that he didn't have to separately fix the constants, that they come out, a range of constants in different parts of the multiverse come out from these laws he's ordained. And then life comes out in one of these. But it's not automatic that even if you do have a multiverse, that one of them will necessarily have life. I mean, just like you could have, well, it's just like you could have an infinite line that does not go through some region of space. I could have a line here, and it doesn't go through my hand. And even though the line's infinite, you could have an infinite number of universes without any of them having life. Right, sure. So I think God did make choices so that life could exist. But I personally think that he made the choice, an elegant choice of fixing the form of the laws, but not fixing the individual constants, and that different parts of the universe have different effective constants. And then some of them are suitable for life as God wanted. But if you admit that there are multiple universes, and different universes can have different constants of physics, like the cosmological constant, that really undermines many of the arguments for God, because in the argument as you presented it, I could take God out of that picture and just have the laws of physics generating all these different possibilities, and then one is the one in which we find ourselves. Well, it does remove one argument for design, although that's a fairly recent argument, because of course it's only been the last few decades that we've known about this fine-tuning. But it's true that many theists have picked up on this problem of the fine-tuning, and say, aha, this is a problem that God solves. And I guess I'm taking... And multiple universes undermine that. So I think, right, in a sense it's a little bit analogous to the way that many people view that Darwinian evolution undermined a particular form of design of individual biological creatures. See, I think God designed the whole process, and the whole process did lead to us, as well as other beings that may be in other multiverses. It would lead to other creatures that are somewhat like us, but different. So I don't believe that Darwinian evolution undermines design as a whole. It undermined a particular design argument, and I think the multiverse might undermine a particular design argument that God chose these particular designs, but it doesn't undermine the overall design argument, and it certainly doesn't undermine the existence of God. It just undermines one small argument for God.