Sunday, July 29, 2012

The battle over "Nothing"

by Salman Hameed

Why is there something instead of nothing? Why does the universe exists? These questions are at the boundary of science and religion. An explanation for the Big Bang would not answer these questions, as we may have a multiverse, and the explanation of the origin of a multiverse may still need to explain why we have the laws that produced a multiverse. From a scientific (and practical) perspective, we can never use a supernatural explanation. That would stifle inquiry - as we can never know if we have reached the actual limit of our understanding or not (there is always an origins questions behind every origin explanation). But scientifically we cannot say if ultimately there is a God that is the cause of why things exist or if there isn't one. The opinion on God (or lack thereof) is ultimately a matter of faith.

This point is explored in more detail by a new book by Jim Holt, Why Does the World Exist? In the mean time, here is an excellent review that talks about the meaning of nothing:

Holt is just the man for the something/nothing detective story because he is one of those rare individuals who can speak three distinctive languages fluently: the advanced mathematical language of the quantum cosmologist, the sometimes-indecipherable language of post-modal philosophy and theology, and, oh, right, the third language: English. In fact he can write it with extraordinary subtlety. His prose is both suspenseful—his subtitle is "An Existential Detective Story"—and stringent in an exemplary way.
The new argument that has broken out over the meaning of nothing is one of the most profound and fascinating controversies in modern thought.  
The conflict is certainly more important than the Higgs boson business, because the discovery of the Higgs, the (supposed) Final Particle, the one that gives all other particles mass, just points up how little we know about nothing. It points up once again the true missing piece in our understanding of the cosmos: If the Higgs boson makes matter possible, what makes the Higgs boson possible? How did it come into being from nothing? And if they tell you the laws of physics created it, made it necessary, as some do, then what created those particular laws? And where are they in the midst of nothing? Hovering above, or somehow woven into nothing? But that would imply nothing has a capacity to contain laws, in which case it would no longer be nothing; it would be a vehicle for abstract equations. 
And how do abstract laws have what Jim Holt calls “ontological clout”—the ability, just by existing conceptually somewhere (actually nowhere, since nothing has no “where”), to bring something into being from nothing? 
And so on in an infinite regress into the abyss of the ancient but still hardy Aristotelian First Cause problem: Any proposed First Cause such as “the laws of quantum mechanics” will presuppose a cause previous to it that caused the purported First Cause.
So what is "Nothing"? No, it is not the vacuum. Holt found this answer which comes close to nothing:

It takes Holt 150 pages or so of travelling the world interrogating the nothing theorists to find one who gives what he believes to be an adequate definition of nothing—the nothing we seek to find, the one that qualifies for the “how do we get something from nothing” question. 
This comes in his conversation with the physicist and cosmologist Alex Vilenkin, and it’s worth listening to what a stringent definition of nothing really is: 
“Imagine,” Holt asks us, paraphrasing Vilenkin, “spacetime [the matrix we live in] has the surface of a sphere. ... Now suppose that this sphere is shrinking like a balloon that is losing its air. The radius grows smaller and smaller. Eventually—try to imagine this—the radius goes all the way to zero.” 
Pause for a moment to think of a sphere whose radius has gone “all the way to zero.” No time. No space. It’s hard—but not impossible—to get your head around it. Now back to Holt: 
“The surface of the sphere disappears completely and with it spacetime itself. We have arrived at nothingness. We have also arrived at a precise definition of nothingness: a closed spacetime of zero radius. This is the most complete and utter nothingness that scientific concepts can capture. It is mathematically devoid not only of stuff but also of location and duration.” Nothing is nowhere. 
It’s not anything like a chunk of vacuum because a chunky vacuum has extension. It’s not anything like anything. It’s nothing.
This is a good explanation. However, I'm not convinced that this is absolute nothing.  After all, the space-time matrix that we live in may only be part of our universe. If there are other universes out there, then they will have their own respective space-time matrices. From that perspective, a shrinking of our space-time sphere to nothing will result in a nothing of our universe only - and we will run into the same problem of something existing outside of our nothing!

However, the review is actually quite good and it also mentions the whole flap over Lawrence Krauss' latest book, A Universe Out of Nothing. And yes, the problem is that Krauss' nothing is actually something (quantum vacuum). Read the full review here.

Also see this earlier post: Multiverse Theory - Leave it to science


Anonymous said...


Ali said...

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Ali said...

Intersting thing is nothing is not something you can visualise or even imagine, imho. Shriking the radius of the sphere to zero will make the sphere nothing. But thinking of a nonexistent sphere also gives the same effect.

You can imagine the universe shrinking into a zero raidus. But with that you are also non-existent. So where is the real 'nothing' that you have imagined?

In earlier drafts, I tried to briefly address this point in my book but then it was leading me nowherre. I was just going round and round, i thought. So I had to delete a big chunk of what I wrote and said it in perhaps a paragraph or two. In the end, i said that I could not imagine what 'nothingness' is like. :)

Salman Hameed said...

Thanks Anonymous.

You are right that it is hard for us to imagine anything beyond our universe (since we are a product of this universe, so our brains are shaped for these dimensions). But we can indeed think about an expanding space. In that instance, we have to be clear that the universe is not expanding "in to" anything - but rather that it creates space because of its expansion. I think this can help in visualizing the absence of space (i.e. the disappearance of space-time). But as I mentioned in the post, we may be able to find outer universes, and then we may consider this no-space zone as a different form of a vacuum. This is the reason, all we can do is stay tuned for more science.

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