A debate recently erupted on the web in physics and philosophy of science circles about some comments made by Lawrence Krauss, author of a new book A Universe from Nothing. I learned about it from a rather good blog article by Sean Carroll.
The net is this: Krauss states that physics can now explain why the universe exists at all, without help from religion or philosophy. He also suggested that philosophers had been less than useful in making this clear. The philosophers were peeved.
As a digital physics person, I feel compelled to chime in. This is because Krauss’s way of explaining the spontaneous appearance of the universe is to define ‘nothing’ as a fluctuating quantum state, and then to show how such a state can give rise to a spontaneous universe.
But there’s a problem here, and I think it’s what some of the philosophers take issue with. A fluctuating quantum state that has conveniently been around for eternity and which is defined by an infinite-dimensional Hilbert space of possibilities is a really specific, and somewhat unusual, way of defining ‘nothing’. It’s the sort of hilarious goal-post moving that physicists do without even noticing that they’re doing it.
I think the philosophers are tempted to ask: ‘But where does the quantum potential come from?’. Me too. I think Krauss’s answer is approximately: ‘That’s the wrong question. It’s just there. You’re behind the times.’
In my opinion, Krauss’s assertions are lame. Invoking a quantum potential is just another way of saying that the universe was always there, just in another form. To say that this answer suffices is to embed your assumptions directly into your explanation. However, some philosophers’ assertion that the question of why the universe exists can never be answered is also lame. I believe that the logic of digital physics gives you an instant way out of all this waffling.
Think of it this way. Let’s say I have the rules for a universe and start following them on a napkin. I use a really big napkin so that simulated people in that universe can ask about their origins. Is the universe I simulate in the napkin real or not?
If we say it’s real, then we’re saying that something simulated is as real as our universe.
If we say that the napkin universe isn’t real, then we have to ask whether we’re in someone else’s napkin simulation. How would we ever know? Does that make us possibly not real either?
There’s no way to tell if you’re in a simulation or not, because everything in the universe can be described in terms of information. If we believe in the existence of logical physical laws, then we also believe in the potential for a simulated universe.
One might say, in response to this, that regardless of how simulated the universe might be, it’s still happening, and therefore there’s some level at which the universe is real. There has to be something at the bottom of things that’s concrete because we’re here.
But that’s wrong.
What is this magic commodity of reality that let’s us know that we’re actually happening? It’s not something that manifests as information because it can’t be simulated. This means we can’t measure it or even talk about its properties. In fact, presupposing that it exists is a form of mysticism because it can never be proven. If it wasn’t there, and the universe wasn’t ‘happening’, how would you know?
The simple answer often given is: ‘Because otherwise I wouldn’t be here.’
But this is circular and not useful. It’s a form of faith. It’s a bit like saying that Jesus loves you because you’re loved by Jesus. It doesn’t cut it.
But here’s a question that gives us another way to look at the problem:
Does the number three only exist when someone is counting? Regardless of what units it occurs in, there’s an attribute of more-or-lessness that has a consistent effect on the universe. That attribute is so absolute that it’s conserved rigorously in physical law, defines how organisms develop, and determines which stars turn into black holes. It’s abstract enough that human beings all over the world support cultures containing the same exact notion. Quantifiability clearly exists without any of us paying attention to it. And so, therefore, does three.
Many people will tell you that three is a human creation, and something that doesn’t exist without the act of counting. But this is also wrong. Couples of any sexually reproductive species will tell you that having someone else try to muscle in on the act of intercourse is interference. Three is a crowd in any language.
But if three exists, yet isn’t physical, we have another form of existence on our hands. This existence is purely informational, and thus a lot more concrete than our nebulous sense that ‘something is real down there because it is’.
Stating this same idea more broadly, if you have a sequence of expressions that follows a simple rule, it will look the same now matter how the rule is followed. Three is still three, whether it’s measuring cows or planets. Thus we can say that logical sequences have the same kind of existence as three. Indeed, three is an example of a term in such a sequence–the set of integers. And if logical sequences can exist in this informational way, then so can universes.
This makes things tidy and simple. We don’t have to propose two kinds of existence, only one. And all sequences that have a complexity less than our own universe can be said to exist because we know that we do. No god. No magic. No quantum potentials. No mysticism. Just an assertion that certain kinds of mathematical series can be known to be ‘real’ because we occupy an instance of one, and that’s it. In a way, it’s rather like the mystical notion of ‘something is real down there’ that we discussed before, except that this time, the base reality we invoke is informational, and therefore amenable to examination.
The only question we can’t answer in this paradigm is why logical order exists in the first place. But in order to ask this question, you need logical order to frame it. (‘Splange’, for instance, isn’t a very satisfying answer, but it’s fine if you’re not insisting on logic.) So at this point, we’ve pushed as far to the edge of our fishbowl as we can get, which is as far as it makes any sense (literally) to push.
However, while we can’t follow the chain of ‘why’ backwards any further than this, we can push it forwards, and use the same kind of logic to refine our understanding of nature more deeply. We can use the same logic to demonstrate that the laws of the universe will be minimally implemented for the complexity that we see, and explain why physical laws seem regular in the first place. We can also demonstrate very simply why the idea of a god is both irrelevant and ridiculous. The same logic inexorably marches us to the conclusion that the implementation of the universe is discrete. But I’ve probably covered enough ground for now. We can unpick the rest of reality later.