Sunday, October 29, 2017

Negative and positive energy

In my last post, I reviewed The Grand Design by Stephen Hawking and Leonard Mlodinow. I talked there a little bit about negative and positive energy and how they thought it might explain how the universe could come into existence from nothing. I said I didn't think the argument worked.

Well, I had a conversation a while back with somebody where that same idea came up, and I thought I'd share what I said so as to expand on what I said in the book review. So here ye go. . .

Unless I have some big misunderstanding, it seems to me that Hawking, Vilenkin, Krauss, etc. are eqivocating on terms like "negative energy" and "zero energy." Energy has positive ontological status. In other words, it actually exists as a concrete thing.

So what does "negative energy" mean? It can't mean "less than energy," because that would imply that not only does it not exist, but it less-than-exists. But that can't be the case for anything concrete. I have two cats.* If one ceased to exist, then I'd have one cat. If they both ceased to exist, then I'd have zero cats. But I can't have negative cats. What would that even mean?

So "negative energy" can't mean "less than zero energy." That's incoherent. "Negative energy" is kind of a misnomer that I think Krauss et al exploit by equivocation. "Negative energy" is actually a positive something. It has positive ontological status. It actually exists.

So I don't think balancing "positive energy" and "negative energy" and arriving at "zero energy" means that there is actually no energy in the universe or that the universe could've come into existence uncaused out of absolutely nothing. If there was a state of affairs in which nothing at all existed followed by a state of affairs in which both negative and positive energy exist, then even if they sum to zero, you'd still have a situation in which something came into existence out of nothing.

*I had two cats when I wrote that, but I'm down to one now. :-(

Thursday, October 19, 2017

Review: The Grand Design by Stephen Hawking and Leonard Mlodinow

This is a copy of my Amazon review of this book. Be sure to click over there and click "like" so I can feel good about myself. :-)

This book make a pretty simple argument in a pretty simple way. The argument of the book is that God is not necessary to explain the origin of the universe or the apparent fine-tuning of the universe. Both can be explained by M-theory. M-theory predicts something like 10^500 universes with various laws and constants. The wide variety of universes with different constants and laws provides the explanatory resources to account for the fine-tuning of this universe for the possibility of complex chemistry and therefore life. The inclusion of gravity explains the emergence of the universe from nothing.

The book is not technical at all, and it doesn't go into any detail about much of anything. It's very simply written and easy to understand. It's also fairly short. I would recommend it for those reasons.

But there are problems with the book. First, the book is unnecessarily polemical. It starts off criticizing the whole discipline of philosophy as being obsolete. The problem with this criticism is that the authors engage in philosophical reasoning and speculation throughout the book, sometimes poorly. The authors also take pot shots at various kinds of theism throughout the book that seem designed to poison the well or even vent the authors' antagonism toward religion rather than contribute to any argument.

Second, the argument at the end of the book for how the universe could spontaneously pop into existence from nothing seems fallacious. It's based on the fact that positive energy of the matter in the universe is perfectly balanced by the negative energy of the gravity in the universe such that the net energy in the universe is zero. I can see how that could work out as an explanation for how the universe could pop OUT of existence, but I don't see how it serves as an explanation for how the universe could pop INTO existence. It could pop out of existence because the negative and positive energy interact and annihilate each other. But how could the universe pop INTO existence from nothing at all? In that situation, there's no positive or negative energy because there's no mass and no gravity.

Also, as I understand it, M-theory does not predict that any universe pops into existence spontaneously from nothing. Rather, universes are caused to come into existence by the collision of previously existing branes. Maybe I've just got some big misunderstanding, though.

Another weakness I found with the book was that while the authors explained near the beginning of the book that science works on models, and models only have practical value without having to actually describe what the physical world is really like, they argued throughout the rest of the book as if the models of physics accurately describe the world the way it really is. In fact they went so far as to say that M-theory MUST be true because it's the only candidate for a complete theory of the universe.

Based on other things I've read by Stephen Hawking, I'm skeptical that he had much to do with writing this book. I suspect Leonard Mlodinow wrote most of it and that Hawking's name is in big letters on the cover because his name sells better.