This episode illustrates how fine tuning presents a major problem to the ordinary scientific method for explaining phenomena in our universe. Through an analogy from ethical systems, it demonstrates why a paradigm shift is needed to solve the mystery of the constants.
Essay Version of Episode 4
Maybe this is a good time to discuss just how we ended up with the idea of writing a book and making this podcast. About 15 years ago (around 2008), we came across the discovery of fine tuning of the constants. Fine tuning refers to the fact that there are strange numbers seemingly built into the fabric of the universe. If they're even a little bit different, then nothing - not stars, not planets, not atoms, not life - nothing could exist at all - certainly not the way we know it. We started to recognize that this provided an incredible argument for an intelligent cause of the universe, far better than the design argument from biology.
But we realized that since this argument involves physics, it would be really hard to convey to people in a simple and convincing way. While we discussed the argument with our friends, we pretty much left it at that. A few years later, we came across the multiverse. And that changed everything!
Scientists were putting out articles and videos explaining fine tuning, discussing how in their opinion, the only explanation - other than God, which they really didn't want to say - was a multiverse. That was the only other explanation for them, a seemingly untestable hypothesis of an infinite number of unobservable universes where everything possible happens. We realized that the best way to convince people that there really was a good argument for an intelligent fine tuner was to show them the multiverse.
If scientists are willing to change the scientific paradigm because of the problem of fine tuning, even a layman could see that there must be a major problem that motivated such a great shift in their approach.
This epsiode will show how fine tuning presents a serious problem to the scientific paradigm of explaining our universe. We’ll illustrate how it implies a type of reverse causation, in which the resultant universe seems to be the cause of the laws themselves. We’ll show how this is not just another unsolved mystery in physics, but the nature of this difficulty is so great that resolving it demands an entirely new type of explanation, even according to scientists.
We'll explain, in simple terms, what in the world reverse causation is and why even scientists agree that the discovery of fine tuning necessitates a major paradigm shift.
How the Reverse Causation Problem Shows that the Constants Cannot be Fundamental
Let's review the basic idea of fine tuning and then show why its discovery truly warrants a new paradigm to solve the mystery of the constants.
Science usually begins with some observation it seeks to explain. A successful scientific explanation shows how this phenomenon is a consequence of the laws of nature which caused that thing. In a sense, the goal of physics can be summarized as discovering the fundamental laws of nature which cause our universe to emerge as a consequence of these laws.
Now, as strange as it sounds, fine tuning seems to indicate that it is not the laws which cause the universe, but just the opposite. It's the universe that causes the laws to have the form that they do. To appreciate this novel idea, we need to first recall physicists' realization that, as far as the laws of physics are concerned, the constants of nature could have taken on a wide range of possible values, and for some constants, any value whatsoever. This was the starting point of the mystery of the constants: what caused the constants to take on their seemingly arbitrary values?
Next, the discovery of fine tuning revealed that while theoretically, the values of the constants could have been anything, they were indeed very special in that only these values eventually resulted in a complex universe with atoms, molecules, stars, galaxies, and so on. Therefore, it seems that the constants have their specific values in order to allow a universe with these specific complex structures to emerge.
This seems like reverse or backward causation. How is it that the consequences that emerge from the laws and constants - the atoms, planets, stars, and so on - how is it that they are the cause of the values of the constants themselves? This is the exact opposite of the ordinary scientific paradigm which explains how consequences are caused by the laws, not how laws are caused by their consequences.
In other words, we're explaining, through fine tuning, why these constants have these values; because if they were different values, you wouldn't get stars, atoms, or galaxies. So the reason why the constants are these numbers is because if they were different numbers, you wouldn't get these things. These things are the reason why the constants have their values! That's backward! You're explaining the values of the constants by saying that if they were different values, you wouldn't get these things. You're explaining the laws by the consequences of their laws. That's backward or reverse causation.
We’d like to give an analogy for the two different types of causation - once again from ethical systems. There are two different paradigms that explain the laws in any ethical system. The first is a rule-based ethics. Rule-based ethics is an ethic that is based upon absolute rules, rules like, “Do unto others as you want done to yourself.” Another law might be the principle of the sanctity of human life, that you're never allowed to murder. Most ethical systems that we know of are grounded in foundational rules from which all the other laws emerge.
On the other hand, there's another type of ethical system, sometimes known as consequentialism. This is an ethical system which is based on its consequences. The idea is that the ends justify the means, no matter how horrific those means are. A given society might choose certain goals as their objective, i.e., the goals of making a society that is wealthy or has happy people or people who pursue pleasure to the highest degree, and they build the laws of that society in order to bring about those consequences.
With these two ethical paradigms in mind, let us imagine that we start out with rule-based ethics. And every ancient civilization that we study uses rule-based systems, and assume that this rule-based system is successful at explaining all societies that we see. But then we find a new mystery city. And when we try to look at the laws of this city, we can't fit them into any rule-based system. We find in this city, for example, 25 crazy laws that defy all the ethical rules that we know of.
For example, imagine a crazy law, that this society allows you to kill old people or sick people. As abhorrent as that may sound, we try - again, we've been successful trying to understand all civilizations based upon some sort of rule-based system - and we try to use our old paradigm to try to explain the laws in this society. But as much as we try, the laws are just so crazy and they seem so unethical, that we can't figure out a system of laws, of rules, of ethics at the foundation of this society.
However, we then realize that perhaps we need a new paradigm, perhaps this society is following a consequence-based ethics. And when we look into it, we realize that this society was actually the wealthiest society in the world at its time. And we end up looking into the laws, as unethical and horrible as they may seem to us, we see that these laws are perfectly fine tuned to bring about the maximum wealth for its participants. And we see how, for example, the reason why they're killing old people and sick people is because that helps preserve the resources for the younger people who are going to be able to make more money, and so on.
Imagine we would rigorously show that again, as unethical as these laws sound to us, these 25 laws are totally explained by this new paradigm, that these laws are maximized to be able to bring about a wealthy society, to bring about the consequence of the type of society which they're trying to create, a wealthy society. And if we discovered that, if we were to show this in a rigorous manner, we would realize that there's a type of reverse causation going on in this society. The ordinary way we explain a society is we find out the ethical laws in the society and we see how those laws naturally cause a certain type of society to emerge. But in this society, in this crazy society, the desired end, that is maximum wealth, is the cause of the laws themselves.
While most people would probably say that whose who will do anything to maximize their wealth should be called unethical people, we are simply making an analogy to compare it to physics.
The normal scientific paradigm tries to explain the laws of nature, the rules that govern our universe, in its own terms, in terms of physics, without making recourse to the consequences of what the laws are going to produce. As we explained, physicists typically use principles like simplicity, mathematical consistency, symmetry, and beauty, in order to discover the deepest laws of physics.
But fine tuning shows that instead of using these types of principles, you have to make recourse to what the consequences of these laws are going to be. In other words, the form that the laws take on - that is, the values of the constants - is determined by what the universe is going to look like based on these values. That is a totally different way of trying to explain the laws of physics from the scientific paradigm that physicists are used to. It's a complete shift in how you're analyzing the laws of physics.
The First Two Theories Ignore Fine Tuning
Now that we see why fine tuning necessitates a paradigm shift, let's revisit the two different approaches that scientists originally had for solving the mystery of the constants: that of the master law theory, and the uncaused constants theory. Let's recall these one at a time and see why fine tuning completely undermines both of them, as they are both explanations within the old paradigm of science.
The first approach was the hope that some master law, some grand theory of everything, would determine the precise value of every constant as a mathematical consequence of that law. Somehow, there's going to be this theory of everything and because this theory is true, every constant just has to happen to have its specific value. Now, although the realization of this dream seemed overly optimistic - because how could a qualitative law generate the precise values of all the constants - some scientists still held out hope. However, the discovery of fine tuning seems to fully undermine this approach.
This approach would have to maintain that the numbers - which must exist purely because of a theoretical mathematical consequence from this theory of everything - happen to coincidentally also be the precisely fine tuned values necessary for the emergence of the complex ordered universe. It's a complete coincidence that whatever this law is, it dictates that these 25 numbers have to have the value they have, which coincidentally is the numbers you need to get atoms and molecules and stars and planets. There's no real reason why that should be the case. It's just a big-time coincidence. It doesn't make any sense! It's not explaining the relationship between the two. Physicist Frank Wilczek wrote the following in support of this point:
It is logically possible that parameters determined uniquely by abstract theoretical principles just happen to exhibit all the apparent fine tunings required to produce, by a lucky coincidence, a universe containing complex structures. But that I think, really strains credulity.
Wilczek is saying that after the discovery of fine tuning, it is no longer reasonable to dream that physicists will discover a master law that determines all the constants. To hold on to optimistic hopes for discovering this law, even if you discover this law, you would still be forced to posit a coincidence of the highest order, it's just too wishful, even for dreams.
Besides the fact that such a dream is far-fetched, the approach of continuing to search for a master law despite the discovery of fine tuning makes a methodological error, that of holding on to an old approach despite the emergence of new clues. In particular, the original mystery of the constants was to explain their values, which seemingly have no significance at all. At that point, it was reasonable to hope that maybe we'll find a master law that would explain where these strange numbers come from.
However, once scientists actually found significance in these numbers, that they are fine tuned for a universe with order, structure, and complexity, we have found our clue. Based on this clue, we must figure out the appropriate next step to help solve the mystery. In other words, we must deal with the problem of fine tuning. To instead ignore the discovery of fine tuning and continue to search for a master law to explain the constants, irrespective of fine tuning, is a poor methodology. Proper methodology suggests that clues should be utilized to help advance knowledge, not ignored in order to hold firm to old approaches.
This exact same problem exists with the second approach to solving the mystery of the constants: the claim that the constants are uncaused fundamental facts of reality that can’t be explained by any deeper law.
That theory was plausible - albeit not very beautiful - when the only problem was the mystery of the constants. But once fine tuning was discovered, scientists were forced to abandon that theory as well, as it too doesn't incorporate new knowledge about the constants. Just like the master law theory, it ignores the connection between the values of the constants and the resultant universe, which, according to both of these theories, is entirely coincidental.
Let's explain the problem in a little more detail. The uncaused constants theory claims that an essential part of the nature of reality is these 25 numbers. If we ask, “Why do they have these specific values?” this theory would answer that that’s not a valid question: they just are that way.
Now, if that’s true, then so be it. While it’s not beautiful, if no matter what the values were, everything would work out more or less the same, then someone can claim that they are these specific numbers because that’s just the way the world is.
But now we see that it’s not true. If an electron were a different mass, there would be no atoms. But nevertheless, if you ask again, “Why is an electron this big?” the uncaused constants theory will still have to respond, “It just is this way.”
The response is completely unchanged by the new gain in knowledge. The theory ignores the fact that if they were any different, there wouldn’t be atoms and molecules. The theory would have to maintain that it happens to be a massive coincidence that the constants have these perfect values. It ignores the obvious connection, the fact that the discovery of fine tuning has provided a piece of knowledge - that if the constants were any different, you wouldn’t get a universe with all this complexity.
And that’s a reason to reject this theory entirely. Because it's stuck in the old paradigm. It’s not willing to embrace the scientifically revealed connection between the specific values of these constants and the resultant complex universe.
Let's return to our analogy to show why it's a bad methodology to ignore new knowledge and instead stick to your old theory. Back to our city, which had these 25 crazy laws that seemed to us to defy any law-based approach to ethics. They seemed totally unethical and we had no way to explain them.
Though it was a big mystery, we realized we could actually explain the laws of this society based upon an ethics that is centered around the consequences that this society was designed to bring about - the consequence of a wealthy society. And all 25 laws were successfully explained by this premise that the laws were built around bringing about that objective.
If instead of accepting the explanation of the rules of this society based upon their consequences, we would instead insist on explaining it from a rule-based perspective - to try to come up with ethical principles which would somehow justify the killing of old people or sick people - to take such an approach would be ridiculous. After all, we have knowledge that this society is built around the goal of attaining maximum wealth. We can't just throw that out and say, “We don't like that. And therefore, we're going to try to stick to our old paradigm of a rule-based ethical system.” That would be bad methodology.
Let's just add the caveat one more time that we are not monsters. We're not saying it's better for society to pursue wealth and to kill people who are sick or old. It's just an example in order to help clarify this idea in physics.
The point is that both theories in physics, the uncaused constants theory, and the master law theory, weren't very good to begin with, they didn't really work. That's why Feynman called explaining the constants one of the greatest mysteries in all physics. But after the discovery of fine tuning, that the values have to be within a specific range in order to get a complex ordered universe, they're not just theories that aren't very good - they simply don't work at all, because they completely ignore the newly discovered relationship between the values of the constants and the resultant universe. Physicists needed a new paradigm that was capable of incorporating this new information, and that ultimately led them to the multiverse.
A New Paradigm is Needed to Explain the Values of the Constants of Nature
The point is that the discovery of fine tuning called for an entirely new type of explanation for the value of the constants. Namely, it requires an explanation for how the laws of nature can be caused by their eventual consequences.
However, one may reasonably hesitate to seek out an explanation that breaks from the standard scientific paradigm. Instead, why don't scientists suggest that maybe science will one day discover a theory that can explain the values of the constants in a manner that doesn't call for such drastic measures? Why are multiverse scientists so confident that this problem calls for a new type of solution? Wouldn't it be better to admit that we just don't have a solution at the present time, but hopefully in the future, science will provide a theory that explains the problem posed by fine tuning?
Some scientists - especially the ones that hate the multiverse and think that God is always a bad explanation - actually try to say something like that. But the mainstream scientific view is that fine tuning is different and you can't just say, “Wait and see.”
Here's why. It's certainly true that not every question must be immediately answered. And not every problem calls for a paradigm shift. That's exactly the God of the Gaps fallacy we spoke about last time. More often than not, even a very difficult problem, a gap in our knowledge, demands time and patience to be solved.
For example, the mystery of the constants prior to the discovery of fine tuning was just such a gap. The correct approach was to wait and see if new information would come to light which would provide a clue that shows that the numbers are not completely arbitrary. And, in fact, that early patience was rewarded with the discovery of fine tuning, which demonstrated the significance of these numbers with regard to chemistry, biology, astronomy, and so on.
However, the problem of fine tuning itself, it's not a gap that indicates ignorance - fine tuning is knowledge about how nature operates. Fine tuning is knowledge that physics is working differently than we originally thought. This provides the clue to solve the mystery of the constants. It doesn't make sense to say, “Wait and see” after you find the information you're looking for just because you don't like where it's pointing.
Going back to the ethics analogy, we have this city that has these strange, seemingly unethical laws. And we've discovered a theory that the laws in this society are based upon the consequence of making the society the wealthiest society in the world. Imagine we said, “You know what, I don't like that theory. I'm going to wait and see. And maybe we'll find another explanation. As unethical as the laws sound, maybe there's some other explanation. It can't possibly be based on the wealth. Let's wait and see if we can find another clue.”
But you found the clue! The clue is that all the strange laws in this society are explained by the purpose of maximizing the overall wealth of this society. To ignore the new information and continue to say, “Wait and see” is not a good methodology. Rather, it stubbornly clings to a failed paradigm and refuses to accept new, perhaps shocking, discoveries. That's a bad methodology.
Multiverse as an Explanation of the Constants of Nature
Now that we understand why physicists feel that the problem of fine tuning is so compelling that it justifies positing something as revolutionary as the multiverse, we’re in a position to discuss the natural and direct implication of fine tuning - that there exists an intelligent cause that fine tuned the constants. And that is exactly what we're going to do next time.
But before we move to next time, let’s make sure we completely wrap up this episode. You may suggest that it's not quite obvious at this point what reverse causation has anything to do with multiverse, and it's not clear what kind of paradigm shift multiverse entails. While we're planning a separate miniseries on multiverse later, let's explain those basic points now, at least briefly.
To do so, we'll need to understand a little bit about how the multiverse explains the fine tuning of the constants. There are really three points:
First, as we explained before, chance is a really bad explanation if there's only one universe. If there's only one universe, the odds of getting all the constants exactly within the ranges, it's just so so unlikely, it's so improbable, that if there's only one universe, nobody will say chance.
Second, if there are an infinite number of never-before-observed-universes, and each of these universes in this infinite array of universes has a different value for all the constants, then chance is a great explanation because at least one universe has to have the right values. If there's an infinite number of them, then every single possible combination exists. And one of them is going to have all the values of the constants lined up right in the proper ranges.
Now, that brings us to the final point. Perhaps someone will ask, “Well, what are the odds that we're in that universe when there's an infinite number of universes and almost all of them have the wrong values of the constants?” That's where something called the anthropic principle comes in. This principle states that any universe capable of sustaining intelligent observers has to be the one that we're in. If we're looking at the laws of nature and we want to know, what are the laws of nature that we see, we have to see laws that are designed and fine tuned for us to be able to exist. It’s impossible for us to exist in a universe that doesn't have constants that are fine tuned for us to exist because there are no intelligent observers in universes without fine tuned constants.
So in a certain sense, multiverse explains the apparent reverse causation by saying that there is an observer bias, and that anytime somebody is capable of being intelligent enough to formulate the question of what are the laws of nature, and why am I here, they're going to be in a universe which has laws of nature that are fine tuned for the possibility of having an intelligent observer. So it says the reverse causation is not a true causation. It's not like we cause the laws of nature in a true direct sense. It's only like an indirect sense that we're going to be in a universe where we perceive laws of nature that are fine tuned.
So multiverse takes this relationship between the fine tuned values of the constants and the resultant universe seriously. It makes that connection and it says that intelligent observers will see fine tuned values of constants, and we won't see any of the other universes in this hypothetical multiverse. As opposed to the other two theories we discussed before, the master law equation and the uncaused constants, where they completely ignore the relationship, multiverse uses that relationship to posit an infinite number of universes where the constants are not fine tuned. We’re not going to take up the strengths and weaknesses of the multiverse approach right now, but we want to make the point that it does take this relationship seriously and explains it through an observational bias.
So it turns out that the paradigm shift of multiverse really exists in two facets. Firstly, multiverse explains the known laws of nature based on intelligent observers, like human beings. That's in fact why they call it the anthropic principle - anthropic means relating to man. This is completely different than the way standard physics tries to explain the observed laws of nature and the constants without making recourse to our own existence.
The whole idea is that multiverse is explaining the constants based upon the fact that only these constants will be able to result in intelligent observers. They're saying that even though there are infinitely many universes in our universe, the constants in our universe are the values which they are because those are the only ones that could produce intelligent observers.
That's why we mentioned last time that it was so important for multiverse scientists that fine tuning wasn't just for molecules and stars, but it was specifically for intelligent life. Without the fine tuning being connected to intelligent life, it doesn't work with their explanation for the fine tuning and for the apparent reverse causation.
There's a second reason why there's such a massive paradigm shift in multiverse. And that's a paradigm shift in the scientific method itself. Up until now, the scientific method has always been understood as demanding that a theory make a prediction that is compared to reality and observation. And that's the true measure of whether a theory in physics is accepted and verified as real science. But an infinite array of unobservable universes that we will never interact with, to call that science, it forces a redefinition from the classical interpretation of the scientific method. And it's for this reason that multiverse theory is still highly controversial, even among physicists.
This has been just a brief explanation of how multiverse looks at the apparent reverse causation problem. But we'll have to wait until later to explore it more in-depth in the miniseries devoted to the multiverse. In the next episode of this series, we'll take up the reverse causation problem and argue that the direct and natural implication of fine tuning is that there exists an intelligent cause that fine tuned the constants - namely God.
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