The A and B Theories of Time

A Universe from Nothing? Part 4: Is Nothing Something?

Last modified on Wed Sep 11 16:50:31 2019

Firstly, I must apologise, since it has been a long time since I wrote one of these posts. Life has just been throwing too much at me. It's now time for me to finish off my earlier discussion of Krauss' Universe from Nothing.

This is the fourth post in a series discussing Professor Lawrence Krauss' work A Universe From Nothing. In the first post, I gave an introduction to the underlying cosmology, and a quick overview of the rest of his work. Since his discussion of the cosmology was broadly correct, and very well presented, I am (largely) skipping over those chapters and concentrating on those parts of the book which I find problematic.

In the second post, I had a look at chapter 4, which is where things start to go awry. The chapter was about particle physics, and Krauss' claim was the uncertainty principle allowed matter to spontaneously emerge from the vacuum, with nothing before it, albeit only for very short periods. I suggested that his arguments for this were poor, and he made a number of mistakes with regards to the physics.

Last time, I had a look at his chapter 8, which discussed the anthropic principle, which Krauss uses to support his contention of a multiverse. He is discussing a real issue, and it is generally recognised that fine tuning rules out the natural atheist approach of a single self-explanatory universe. That leaves two options; that the universe isn't self-explanatory, but depends on an external principle, which would be an external will, which is the solution favoured by theists. Atheists instead have to suppose that there is not a single universe, but many different universes, each with slightly different laws of physics, so that between them the entire possible gauntlet of physical parameters is sampled. Krauss presents a few models of how such a multiverse might work. There can, of course, be no direct experimental evidence for such a picture, while there can be (and theists argue has been) direct observational evidence supporting the existence of God (namely miracles). But whichever of these two solutions is adopted, we are already moving beyond the bounds of the empirical sciences.

So this point marks the end of Krauss' discussion of the physics. It was mostly pretty good. His discussion of particle physics was poor. The issue is around particle creation and annihilation (or generation and corruption). The issue is where do those particles come from? Krauss' answer was the vacuum. This is based, I think, on an assumption left over from mechanism that particles are indestructible. There is simply a storehouse of unobservable particles (the quantum vacuum), and a visible layer on top, and what particles do during quantum events is move from the storehouse to the visible layer and back again. However, if this proposal is true, then the quantum vacuum would contain a great deal of energy. This effect would show up in gravitational models, and would be much larger than is observed. The alternative approach, which I adopt, is to abandon this mechanistic presupposition and say that substantial change can occur. An actual photon can decay into an electron and positron. An actual electron and actual positron together have the potential of becoming a photon. Energy (the quantum rather than the cosmological definition) is conserved when any one of these possible events occurs, so nothing can come from nothing. Krauss also took more from the uncertainty principle than is actually there, and confused the definition of energy used in cosmology (the stress-energy tensor) with the definition used in quantum physics (the eigenvalues of eigenstates of the Hamiltonian operator in jargon, or a label used to distinguish between different possible meta-stable states in a slightly more understandable language).

But now we leave physics behind us, as Krauss tries to pull everything together. This starts with the ninth chapter, with the unfortunate title "Nothing is Something".

This chapter is wide ranging. It partially summarises what went before, and partly prepares for what comes next. My intention is just to go over the chapter, and point out the mistakes that I noticed (and occasionally commend Krauss for getting something important right). I can't say that I have them all, but nonetheless this is going to be a long post. The title of the chapter itself is a contradiction, which gives us some idea of what we are up against. My response is thus going to be a bit disorganised, jumping from one subject to another, mainly because the chapter I am responding to is the same.

Laws and gaps

Newton was a great physicist. That, I think, everyone admits. But what was his greatest achievement? I would personally say the discovery of calculus and its applicability to physics. Krauss argues,

But perhaps the most important contribution he made was to demonstrate the possibility that the entire universe is explicable. With his universal law of gravity, he demonstrated for the first time that even the heavens might bend to the power of natural laws.

Krauss is, of course wrong, to attribute this achievement to Newton. For example, Aristotle and Ptolemy also explained how the heavens obey natural laws. Of course, Ptolemy's description was wrong, but, then, so was Newton's (albeit less wrong than Ptolemy). Even if we discuss Newton's system, then Kepler was there before Newton. And long before any of these, we had the prophet Jeremiah.

Thus says the Lord, who gives the sun for light by day and the fixed order of the moon and the stars for light by night, who stirs up the sea so that its waves roar— the Lord of hosts is his name: "If this fixed order departs from before me, declares the Lord, then shall the offspring of Israel cease from being a nation before me forever."

The words "fixed order" used by the ESV to translate the Hebrew are obviously different from the word "law," but the underlying meaning is similar. The context shows the immutability of this order: the idea is that God's desire for Israel is so strong that it is as likely to broken by Him as the regular motion of the moon and stars, i.e. not at all. Of course, there is one important difference between Krauss' notion of laws and this fixed order, in that the fixed order is dependent on God, while the laws, as Krauss interprets them, are self-sustaining.

Of course, the notion of laws of physics is a fascinating one, and Krauss' brief discussion doesn't do them justice. He reasons that if immutable laws governed the universe, then that would leave the gods of ancient Greece and Rome impotent. I'm not so sure. The Greek gods are created beings, i.e. in the world. One would thus suppose that they would also be bound by some form of law (perhaps the same as the laws we know about from science; perhaps part of a wider set of laws, of which the ones we know about are only a part, applying only to material beings such as ourselves). But that wouldn't render them impotent: they would still be able to act within the context of those laws.

Then Krauss says that the same logic applies to the God of Israel. This, of course, is a category error. The Greek gods, created beings within the order of nature, would, if the existed, be an entirely different order of being to the Christian God. The discussion here involves the nature of the laws of physics. When the concept was originally specified in those terms, it was similar to the "fixed order" of Jeremiah. The movement of the planets is fully within God's control; but God's regularity and rational nature implies that they would behave in a predictable way. We now explain that regularity through the laws of gravity. But general relativity doesn't change the question. It describes how the space time metric interacts with matter and itself, and how matter moves under different curvatures of space and time. The theist would still attribute those interactions to God. The laws of gravity provides no explanation of why the curvature of space time is linked to the stress-energy tensor. That explanation might well be found in some deeper scientific theory (just as Newton's gravity is explained by general relativity), but at some point that sequence of explanation has to terminate, and since scientific law is only a description of how those interactions proceed, the final layer of scientific question must still leave open the question of why those particular interactions. No matter how deep one goes into science, some question like this would remain. The theist has a simple answer for this: the material universe is not complete, and the laws of physics are a description of God's continual sustaining of it. As our understanding of physics increases, all we do is gain a better understanding of how God operates in the world. The atheist, believing that the universe and its laws describe a complete system, needs an alternative answer.

This theist understanding of the laws of physics predates the atheist one. Indeed, the concept of the laws of physics was originally proposed by theists as a consequence of their theology. Krauss recognises this, and states that there are two ways of understanding the laws of physics: the theological one, and the other that states that "the laws themselves are all that exist." The laws themselves require the universe to come into existence and develop. The laws may be eternal, or may themselves have come into existence through some physical process (governed, presumably, by a higher set of laws).

Now, of course, there is a contradiction between the laws being all that exist, and the notion that things in the universe came to exist; but that's a minor quibble. There is also a problem with discussing the laws both creating the universe and coming into existence. Something can only come into existence in time; but time begins with the creation of the universe. Thus to say that the laws come into existence implies the presence of time in something that is outside time. An alternative perspective would be to say that the laws of physics are continuously generated from something else, as a musician generates music while existing simultaneous with the music. But then, one might as well just skip the middle man, and concentrate on those higher laws of physics.

I note that the laws of physics play a very similar role in Krauss' cosmology as God does in the theist's. They have similar properties; eternal, unchanging, they bring the universe into existence and also drive its evolution and changes, nothing is beyond their grasp and so on. This, of course, arises from the theological origin of the concept of laws. The difference would be that theists describe God as a personal being, while Krauss' laws are an impersonal abstraction.

Indeed, we have to ask what we mean by "exist" here. Clearly the laws of physics don't exist in the same sense that the objects of physics do. An alternative is that they exist as something similar to a Platonic form; but then we have the problem of describing how the abstract world of the forms interacts with the real world. The natural explanation would be to say that there is some law connecting the world of abstractions and the physical world -- but then that law needs to be explained, which puts us back where we started. The third option is that they exist in the same way that a relationship exists. And this makes some sense. The laws of physics describe the interactions, or possible interactions, between beings. However, a relationship between two or more beings cannot not exist in itself. It is a derived form of existence, in that it depends on the existence of the beings. If the laws exist in this sense, they cannot be the creator of the universe. A relationship cannot exist prior to the beings that it relates. Once again, the theist has a simple answer to this problem: the laws of physics describe the relationship between God and the universe in the absence of special acts of providence. They depend solely on God, and come into existence at the creation of the universe. The atheist would reject this model, but needs an alternative, and a coherent alternative at that.

The laws of physics are central to Krauss' argument. Yet he gives no indication what he means when he says that they exist (without turning them into or making them dependent on a God-like being), and this makes it difficult to follow his argument.

Krauss stated that philosophers and theologians continue to debate the question of whether the laws are derived from God, or exist independently. Perhaps we will never know, though the answer, if it comes, will arise. from the exploration of nature. The universe is how it is, whether we like it or not (a very true statement).

Krauss thinks it significant that (in his view at least) a universe arising from "nothing" (by which he means the laws of physics and perhaps some primordial vacuum) is consistent with what we have learnt about the world. But why is this significant? Even if true, it says nothing about whether the laws are a description of God's normal way of acting, or independent in themselves. The theist might even say, that given that God created the universe, and the laws describe God's interaction with the universe, we might expect to see some hints about creation in there. We might conclude (as I do) that the nature of the laws of physics implies the existence of God; but we cannot say from the nature of those laws that they imply the non-existence of God. For the theist, everything that the laws describe is the work of God, and there is nothing in the laws themselves that could demand that they are independent of God rather than describing God's interactions. We need to turn to philosophy to make that judgement.

Of course, there is also the possibility of miracles providing direct evidence for God. Krauss has a brief discussion of this.

Of course, supernatural acts are what miracles are all about. They are, after all, precisely those things that circumvent the laws of nature. A god who can create the laws of nature can presumably also circumvent them at will. Although why they would have been circumvented so liberally thousands of years ago, before the invention of modern communication instruments that could have recorded them, and not today, is something to wonder about.

Krauss seems to be discuss a deist perspective of miracles here: note the laws of physics are something created by God. Again this is problematic, since only beings can be created in the sense meant here. But the main problem is Krauss' assertion that claims of miracles stopped in ancient times. That is certainly not the case. I wouldn't say that all of these accounts are true. Not all have been carefully investigated. Others might just have been chance; a rare event mistaken for a divine intervention. But there are those which are documented, and are confirmed to be genuine. Such miracles are well , particularly among known in some Christian circles. Charismatics and , particularly among Pentecostals are well known for the abundance of miracle stories associated with those churches. They are also attested in countries where the gospel is new and the church growing. But miracles certainly aren't exclusive to those churches: one doesn't have to travel far in many evangelical or orthodox Roman Catholic circles to find miracle claims. Of course, miracles tend to be absent in other churches: some orthodox Protestant churches (those which accept cessationism), and also more liberal churches. These, of course are the churches deny the possibility of miracles today. I think that the dominance of liberal Protestantism and liberal Catholicism in "respectable" Western secular society is why knowledge of these miracle accounts has generally escaped the notice of secular society. The prevalence of people who offer first hand accounts of miracles is stronger in those churches that still believe in the miraculous. Of course, there are three explanations for this. Firstly, the standard theist one, that miracles require a certain amount of trust in God among the people involved. Secondly, that the causation is reversed: that the experience of miracles makes peoples and churches more accepting of the miraculous and drives them in a more charismatic direction. Thirdly, the atheist explanation, that charismatic beliefs only appeal to the gullible and easily fooled. But just because the atheists have an explanation doesn't make the explanation correct. For example, the atheist explanation doesn't account for the often strong evidence for the miracles themselves. Of course, I don't want to deny that there are numerous frauds and false flags out there. But that some of the healers are frauds does not mean that they are all frauds; that some stories are untested does not mean that they are all untested. Krauss ought to have done his research before making an undocumented assertion such as this.

The meaning of Nothing

So, we return to the question "Why is there something rather than nothing?" This question has to be informed by science. Krauss admits that he has changed the meaning of the word "nothing" so much that by a linguistic side-step he has convinced himself that he has avoided any theological questions.

Krauss has rejected defining nothingness as non-being (as everyone else does), since that doesn't allow him to give the answer he likes. Imagine an electron positron pair pops out of the vacuum. We have to imagine it because it doesn't happen in reality; there is always a gauge Boson or Higgs Boson that decays into them. Did the electron and positron exist before the decay? No, but that doesn't mean that nothing existed or they came out of nothing.

There was potential for their existence, certainly, but that doesn't define being any more than a potential human being exists because I carry sperm in my testicles.

Of course there is a distinction between potential existence and actual existence. But potential existence only resides in something that exists actually. Potentiality, of course, is traditionally seen as the middle ground between being and non-being; necessary to avoid a wholly static universe.

Krauss attempts to defend his redefinition of the term "nothing" by turning the tables on his attackers, and accuse them of committing the same error that he is accused of. For this, he needs an older authority who would have accepted his definition of Nothing as Empty Space. He cites Aquinas and Plato.

There are two problems with this. Both Aquinas and Plato explicitly defined "Nothing" to mean non-being. Secondly, neither of them even believed that "empty space" is a coherent concept.

I'll focus my discussion on Aquinas. Lecture 10 of his commentary on Aristotle's physics defines the term void along the lines of what Krauss means by empty space,

The void is thought to be place with nothing in it. The reason for this is that people take what exists to be body, and hold that while every body is in place, void is place in which there is no body, so that where there is no body, there must be void. Every body, again, they suppose to be tangible; and of this nature is whatever has weight or lightness. Hence, by a syllogism, what has nothing heavy or light in it, is void. This result, then, as I have said, is reached by syllogism.

But, following Aristotle, Aquinas rejects the notion of the void. He concludes,

Then he [Aristotle] concludes his chief proposition. And he says it is clear from the foregoing that there is no separate empty space: it is not anything existing absolutely outside a body; or in a rarefied thing after the manner of empty holes; or in potency in a rarefied body, according to those who did not posit a void that exists in bodies as something separated from the fullness of the body. Consequently, in no way is there a void, unless someone simply wants to call matter the void, since it is somehow the cause of heaviness and lightness, and consequently the cause of motion in respect of place. For density and rarity are causes of motion according to the contrariety of heavy and light; but in regard to the contrariety of hard and soft, passible and non-passible are the causes: for the soft is that which easily suffers division and the hard contrariwise, as was said. However, this does not pertain to local motion but rather to [the motion called] "alteration."

We can, of course, question Aquinas' (and Aristotle's) reasoning, and much of it needs to be updated at the very least. Although, as Krauss himself would have to acknowledge, their conclusions hit the mark closer than classical physicists would have realised. There are still quantum and gravitational fields in what was previously thought as "empty space," and topological gluonic objects litter the vacuum, so even if one defines "empty" as a quantum field without excitations that doesn't pass muster either. But nonetheless, Aquinas would certainly not have defined "nothing" as empty space because he did not believe that empty space was a coherent concept. Plato, in the Timaeus, also denied the possibility of the void. There were, of course, ancient philosophers (particularly the atomists) who accepted the void (although still had very different understandings of "space" to modern physicists). Krauss could have cited those writers, but instead he picked on two who most definitely would have disagreed with him.

With regards to the actual definition, Aquinas put it plainly,

For "nothing" is the same as "no being".

"No being" is certainly not the same as "Empty space."

It took me about five minutes of googling to find those quotes. Admittedly, I had one advantage over Krauss: I am already familiar with Aquinas' thought, and knew roughly what to look for and where to look for it. So it might have taken him ten minutes. How much effort would it have been for Krauss or his editor to look it up? There is nothing wrong with citing authorities to back up your conclusions and definitions. Indeed, it is good, as long as you don't rely on the argument from authority but separately provide your own arguments and evidence. But one should make sure that those authorities actually said what you are attributing to them.

The meaning of "Why"

Still, redefining the word "Nothing" is not enough for Krauss. He now realises that he must also redefine the word "Why". The reason for this is, I think, straight-forward. Science doesn't easily answer "Why" questions. To do that, you need to turn to explanations in terms of efficient, final, material or formal causes; and Krauss doesn't care much for those. So instead he wants to ask the question "How?" He justifies this by stating that when most people ask "Why" they really mean "How." He must move in different circles to me. Where I come from, when there are two words with clearly distinct meanings, people generally choose the one most in line with what they want to say.

But, in any case, it is clear that asking "How is there something beyond a quantum vacuum and laws of physics rather than only a quantum vacuum and law of physics?" as Krauss has converted the question into, doesn't have any special theological significance. How questions most frequently reduce to a physical answer. The dispute between theists and atheists centres around the nature of the laws of physics. Are they necessarily dependent on God or independent of God? Giving an answer in terms of these laws does nothing to address the question.

When we try to understand the solar system in scientific terms, we do not generally ascribe purpose to it.

If true (and, of course, there are different meanings of the word purpose; a description of the solar system can certainly be made using Aristotelian tendencies), this is again a red herring. It assumes that the only understanding worth having is the scientific one; something which is again a major point of dispute. I would agree that everything should be informed by the scientific explanation, and consistent with it, but that by no means implies that there is nothing except the scientific explanation.

Krauss then breaks down the "How might something arise from the laws of physics acting on a quantum vacuum" question into sub questions. What conditions are needed to bring about what we observe? How might we find out? All good questions, and these certainly should inform our answer to "Why is there something rather than nothing." But neither can questions such as this by themselves be sufficient to answer the question. Ultimately, the question why there is something is a philosophical one. It must be informed by the science, but necessarily goes beyond the science.

The differences between Scientific and Theological method

Krauss also distinguishes this type of enquiry from a theological one. Theological explanations, he asserts, presume their answers. But, this is only the case to the same extent that scientists presume their answers. A theologian will draw from two sources: revelation and philosophy. The existence of God is made clear from direct observation (for example, from miracles). The task of the theologian is then to explain that observation; and deduce which philosophical model best fits it. The expanding universe is made clear from direct observation. The task of the scientist is then to explain that observation, and deduce which theoretical model best fits the data. If the theologian explains the scientific data by saying that ultimately "God did it," that is not a presumption as such, but the result of the desire to maintain consistency with his own data. There is the bigger question, of how to best combine the philosophical model of theism with the scientific model. We are not going to achieve the full truth by dismissing one part of the evidence out of hand and without good reason; whether the scientific evidence (as done by certain religious groups), or the religious evidence (as done by atheists).

Krauss then asks what advance in knowledge theology has provided in the last 500 years, since the dawn of science. He claims that he has received no satisfactory answer. So I will have a go.

Obviously, the study of theology has provided much insight into questions concerning God. It has also driven a lot of useful philosophical research. There is influence in the fields of literary criticism and the historical sciences (where, if nothing else, many methods were developed as useful tools to better understand the Christian sources, before being applied more widely). Even if we reduce the scope of the question to scientific knowledge, then one could argue that theology was nonetheless a great motivation for many of the great thinkers who brought us to this point: they sought to understand the mind of God through understanding His creation. Equally, Christianity gave us the Western European Universities which provided the infrastructure that allowed science to progress.

But unquestionably the biggest contribution of theology to science was the establishment of modern science itself. Take, for example, the following propositions:

There are regularities in how matter evolves which can be understood as laws of physics. These laws are understandable. These laws are unchanging in time. These laws are unchanging in space, and universally applicable. These laws are in some sense unified. The universe is not irrational, but everything has a sufficient reason to explain it.

These principles are theological in origin. The laws of physics inherit these attributes from God. There is no reason why things have to be this way; and it is of no coincidence that science arose in a society founded on Christian religion and Greek philosophy. Atheists have tried to take away the foundation, but can only do so by leaving themselves with problems such as explaining why physical objects are bound to obey those laws and why the laws of physics have the nature that they do.

Could theology provide more than just the framework for modern physics? I personally believe (and outlined it in chapter 15 here) that, had the theologians their wits about them, and knew enough twentieth century mathematics, they could have gone further than these basic principles. But this is subtle, requires mathematical skill, and away from the main focus and goals of theology. The majority of theologians have had more important (from the perspective of theology) things to do than worry about science. After all, if we were all scientists, we would still be in the dark about justification; but since we have both scientists and theologians, we can understand both topics. Of course, the exchange is not just one way: scientific knowledge should also be used to inform theological discussion. But as for theology's contribution to science (aside from founding it), why should the success of theology be measured by that? One may as well state that science is a failure because it has contributed next to nothing over the past five hundred years to the art of dance. One must judge the success or failure of any endeavour by its own goals. The goal of theology is to better understand God and His relationship to man. One can debate whether modern theological has contributed to that, or simply clouded the waters. But to class it as a failure because scientists rather than theologians uncovered the Schroedinger equation seems to be a strong case of missing the point.

Newton and God's actions.

Newton's work dramatically reduced the possible domain of God's actions, whether or not you attribute any inherent rationality to the universe. Not only did Newton's laws severely constrain the freedom of action of a deity, they dispensed with various requirements for supernatural intervention. … We can describe the evolution of the universe back to the earliest moments of the big bang without specific need for anything beyond known physical laws.

Rarely do you see the difference between the atheist and theist philosophy of physics put more bluntly than this. The key atheist assumption is that the laws of physics operate independently of God. Theists reject that assumption. If Newton's laws describe God's usual actions, then they don't reduce God's sovereignty. Krauss here is begging the question without providing any evidence for his assumption.

I'll deal with the second point first. Krauss discusses the straw men of planets moving because angels push them around. I'm not quite sure who believed this: certainly not anyone who accepted Greek philosophy, which (in this regard) was pretty much everyone in academia before Newton (or perhaps Kepler). Aristotle's explanation of the orbits of the planets, sun and stars was that they were composed primarily of quintessence or an aether, which was predisposed to circular motion in the absence of an external force, just as terrestrial matter is predisposed to linear motion. There are various variants on this theme (such as from Ptolemy, Copernicus and Tycho), but the underlying principle remained. Obviously this explanation is wrong. Though not as wrong as it seemed in Newton's day. General relativity tells us that, without a non-gravitational force, matter is predisposed to travel along geodesics of the space time metric (obviously there are other interpretations; but it is consistent with the modified Aristotelian view). If that curvature is generated by a large mass, then some of those geodesics are, indeed, circles, while others are straight lines towards the centre. Aristotle's mistake was in dividing terrestrial and earthly matter, and thinking that quintessence was restricted to circular motion. But in any case, there are no angels involved.

But what of the other point; that the laws of motion constrain God's freedom to act? Again, this is making the assumption that the laws are independent of God. For if the laws are shaped by God, and maybe a reflection of His intentions, then clearly they cannot constrain Him. The theist will claim that the motion of the planets is both described by the laws of physics and an example of the continual divine intervention in His upholding of the universe. But even so, is God limited in what He can do? Obviously, there is the possibility of miracles: God choosing to act in a different way in response to a different circumstance. Secondly, we also know that Newton's description of physics is wrong. Quantum physics (most obviously in the path integral formulation) tells us that God is not constrained to evolve the universe in a single fixed way, but has numerous options at each moment of time for each particle.

Given that a "God of the gaps" is unacceptable to both atheists (for obvious reasons) and theists (because it reduces God's sovereignty over what is described by physics), Krauss believes that the only refuge for the theist is that moment where physics must surely break down, namely the beginning of the universe. The something from nothing question.

He views the idea of a deity existing outside the universe and yet governing it as extraordinary, and thus ought to be the last rather than first resort. Krauss' opinion, of course, counts for little. Whether something is extraordinary or not depends on ones prior assumptions. The idea of entanglement and electron diffraction is extraordinary if one accepts Newtonian mechanics; for it not to happen is extraordinary if one accepts quantum physics. For the classical theist, God, being perfectly simple in essence, is the most straight-forward answer to the question. Any physical explanation must be complex; one needs to explain the existence of matter, of physical law, and the relationship between the two. At least three principles before we start.

But, of course, Occam's razor is not a good guide in the first place. Not only because which alternative is simplest depends on one's prior assumptions; but because it is wholly the wrong approach. If one has a firm deductive argument, or a view is ruled out by observation, then that should be used ahead of any appeal to simplicity. If not, then we ought to leave all options open until more evidence comes in. Of course, theists claim to have firm deductive arguments for God; while atheists lack such arguments for an absence of God.

Science as a rival to God

So now we come to the classic problem with atheist scientists. They emphasise how we should not take our world-views on authority or without evidence, and rightly so. And then commit the same mistake themselves. Central to the atheist construction of reality is that God and science offer rival explanations. If there is a scientific explanation, then that means that God didn't do it. This is, of course, a statement that the theist would reject every time. As one notable theist put it,

He upholds the universe by the word of His power.

Elsewhere, God is written as being responsible for the grass growing, or lightning, or the tides. Today, of course, we have scientific explanations for this. But why should that mean that God didn't do it? Only if one assumes that scientific laws operate independently of God. Yet the whole scientific project was founded on the assumption that they don't. Scientific law was constructed to reflect many of the divine attributes because it was seen as a description of God's actions upholding the universe with the word of His power.

Atheists will ask what evidence is there that this understanding of physics is correct. To which the obvious first response is to ask for the evidence that scientific law operates independently of God is correct. The second response is to provide evidence; to show that scientific law is consistent with what we would expect if the theist model is correct, as I have done elsewhere.

So when Krauss starts discussing how he is certain that science will provide an explanation for the origin of life, and how evolution by natural selection explains the complexity of life, he ought not conclude that that removes the need for divine intervention. He has glossed over the main question.

Krauss believes that his arguments make it plausible that scientific law can explain how something can arise out of nothing. As I have explained, his argument is problematic. But for the sake of argument, let us grant him it. Let us grant that plausibility is all he needs to undermine the case for God; that aside from this point the case is firmly on the atheist side (again, something which I vigorously contest). He believes that this shows that there is no need for divine intervention. But, if the theist view of physics is correct, all he has done is offer a scientific proof of Genesis chapter 1 or the first line of the Nicene creed.

Inflation and the rise of the universe from empty space

Krauss goes on to repeat his errors about the Newtonian gravitational energy. As discussed before, it is problematic to talk about gravitational energy in the context of general relativity, and general relativity uses a different definition of energy to quantum physics -- which is what the conservation of energy applies to. However, before, in chapter 6, he made a great fuss over how the negative Newtonian gravitational energy exactly cancelled out the positive energy of all the stuff in the universe. Here he is now basing his argument on the contention that the Newtonian gravitational energy is zero. He is responding to criticisms that the zero point of energy is arbitrary. In most scientific theories, these criticisms are correct: all we measure are energy differences. In quantum physics, this is a bit more complicated, since energy is the eigenstate of the time evolution operator, that implies that a negative energy would imply particles travelling back in time. But Krauss is certainly correct that in general relativity, the zero point of energy is certainly not arbitrary.

So now, finally, we come to Krauss' explanation of how matter can arise from the quantum vacuum. As the universe expands under inflation, it will get flatter. The pressure associated with empty space (which is a component of the stress energy tensor) is negative. We are used to positive pressure, where we have to pump energy into a system in order to compress it. Negative pressure means that energy gets pumped into an expanding system. This energy has to go somewhere, and Krauss suggests that it gets turned into matter. Thus, starting from a small speck of empty space, the universe can grow to an enormous scale, containing vast quantities of matter, and appear to be almost perfectly flat with very little variation, as we observe.

Krauss' problem is, of course, the same as he had in the earlier chapter: quantum physics and general relativity use two different definitions of the energy of matter; and it is not clear that it makes sense to discuss gravitational potential energy in the context of general relativity. Thus the mechanism of how stress-energy can convert into quantum energy is unproven. Granted, it might well be that the true theory of quantum gravity, if we ever discover it, will provide us with that link. At the moment that is just ifs and maybes.

Equally, he relies on empty space containing a vast amount of stored energy. His justification for this is the idea that creation and annihilation events in quantum physics involve particles coming in and out of the vacuum, so the vacuum contains a vast store of particles. This model has been disproved because it predicts a much larger value of the cosmological constant than has been observed.

So Krauss' particular model has its flaws. But, nonetheless, inflation is established. The universe did start small and rapidly expand to become what we see around us. The point of dispute is over whether that starting point is empty space. The standard model of cosmology has the starting point as being very hot (energetic) and dense (i.e. with large numbers of photons and other Bosons packed into a small area). That starting point can't really be described as empty space. But, of course, that point is something we don't know much about: our experimental evidence only takes us back to the formation of the microwave background, and both classical general relativity and the standard model of particle physics will break down in the earliest moments of the universe. But, nonetheless, Krauss' contention that the starting point of inflation was a patch of empty space seems to be a rather non-standard perspective.

Now, Krauss admits that the idea of matter arising spontaneously from empty space seems weird. The beauty of science is that it considers irrelevant our subjective notions of what is and isn't weird. But this does not prove Krauss' argument that something can arise from nothing, since even if he is right, "empty space" in modern physics is not non-being. You still have the gravitational field, and the various matter and gauge Boson fields, and with them the potential for excitation. You still have to explain how that "empty space" came about (since Krauss' vision of "empty space" contains structure and energy). One also has to explain where the laws of physics come from. That Krauss wants to address in the next chapters.

I'll take up his case when I next have time to write a post. Hopefully you won't have as long to wait as you did for this one.

A Universe from Nothing? Part 5: Is Nothing Unstable?

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