Friday, July 8, 2011

Where our idea of causation goes wrong or playing dice with the universe

I am going to argue that quantum mechanics undermines our intuitive understanding of causality.

In almost every case where someone begins a debate about the existence or non-existence of something and they make an appeal to quantum mechanics to back up that claim, you should immediately start waving a red flag and telling them to hold up.

So, I'm not going to go into this without seriously backing up my claims.

I want to begin by saying that nothing I'm going to say here is controversial in physics. I'm not going for anything that isn't mainstream stuff. Please, follow my sources for further reading.

I'm not going to give an introduction to quantum physics here. If you really want to read a consumer-friendly book on the subject (and you should because it has implications for all kinds of things), you should start with How to Teach Physics to Your Dog by Chad Orzel. You should also be reading his blog, Uncertain Principles. It is one of the friendliest blogs on the internet dealing with this thorny subject. Another good blog on this topic over at Science Blogs is called Starts With A Bang. Both blogs cover cosmology and quantum physics.

I'm going to assume you at least have a decent grasp of the double-slit experiment, the Heisenberg Uncertainty Principle, the Copenhagen Interpretation and Schrodinger's Cat.

The implications of the double-slit experiment and the Heisenberg Uncertainty Principle is what led to the Copenhagen Interpretation. The reaction to Copenhagen is Schrodinger's Cat. If that is gobbledy-gook to you, stop now and go read the links...

Okay, back? Good.

Now, there are three possible implications for the findings of quantum physics (see below). How you side on these implications determines which of the various interpretations you prefer.

Here's what's probably surprising to my readers. I'm not going to advocate for any one interpretation. I would be stupid to do so. We don't know which interpretation is true. We don't know if we will ever know which interpretation is true. I am agnostic about which interpretation of quantum physics is correct. I have no preferences. I'm in the shut up and calculate camp until we have some way of testing which is correct.

That doesn't mean we can't rule out some interpretations. Additionally, the ones left over after we've ruled the others out have massive philosophical implications (especially for causality).

There are three broad approaches to answering the issue of indeterminacy in quantum mechanics (instrumentalist approaches are not actually attempts to answer the issue but to ignore it).

1. Indeterminacy is a feature of our universe and our classical idea of causality breaks down. Instead, nature is fundamentally probabilistic. (e.g. Copenhagen interpretation).
2. Our universe is determined, but the variables that determine it our hidden and travel faster than the speed of light. (i.e. Non-Local Hidden Variable Theories)
3. Our universe is determined, but the variables that determine it are hidden and do not travel faster than the speed of light. (i.e. Local Hidden Variable Theories)

Everybody who likes our current intuitions about causality want #3 to be true. It isn't.

Einstein was wrong when he said, "God does not play dice with the Universe."

So, what are the implications for #1 and #2 for our traditional view of causation?

Well, #1 says that it is simply incorrect. Probability, not determinism, is what it all boils down to. Once you get the outcome of the probabilities, things are determined afterwards (which is why we experience causality in everyday life).

Non-local hidden variable theories (#2), require faster-than-light travel. That means time travel, folks. Time travel breaks causality too.

So, that's the argument. Our intuitions about causality don't square with our empirical observations of quantum physics. People like Craig can argue that our understanding of causation is a "metaphysical principle" all they want, but if that principle doesn't square with empirical observation, that principle shouldn't be used as the justification for a premise in someone's argument for the existence of anything, especially the existence of anything having to do with the Big Bang.

Next, I'll deal with Craig's objections to this whole line of reasoning.


Edit: The Many Worlds Interpretation of QM does allow for locality and determinism, but it creates entirely new problems for Craig. He would never appeal to it. There is still a probability built into Many Worlds in that there is no way of knowing which universe you ended up with until after the fact. It also means that Jesus only died when Craig believes in this particular universe. There is up to an infinite number of other universes out there where this did not occur. See Craig on infinity to understand why he would balk at something like that.

It salvages causality to spite everything else Craig holds dear. Of course, it might very well be true. Only time and science will tell.

Edit again: The Many Worlds Interpretation isn't entire local. It sort of gets around the local vs. non-local issue by just circumventing it.

Saturday, July 2, 2011

Kalam Cosmological Argument and our intuitions about causes, Pt. 1.

My concerns with the Kalam Cosmological Argument (KCA) rely largely on my objection to the reliability of our intuitions about the way the universe works on the quantum level.

At face value, this has nothing to do with the KCA, and Craig says as much in his 2009 article. Over the next few blog posts I'm going to outline why quantum mechanics (QM) does matter for cosmological arguments (all of them, not just Craig's) and then explain why Craig's argument shouldn't be accepted as it is currently presented and defended.

I am going to be making two claims that I must defend for this line of reasoning to bear fruit:

1. Craig's first premise relies on our intuitions about causality.
2. Our intuitions about causality are not reliable.

In these two lines of thought, we are going to have to ask some questions that bear on subjects like philosophy of science and other fields, such as: What does it mean to say something is caused? and What are the implications of all of this for the scientific enterprise?

I'm going to spend the rest of this post on #1.

As a reminder, the premise under discussion is:

Everything that begins to exist has a cause.
Craig defends this premise with three arguments:

1.1. Ex nihilo nihil fit
1.2. Why only universes
1.3. Experimental confirmation

We must touch on all three.

1.1. Ex nihilo nihil fit

From Craig's 2009 paper on the KCA:
First and foremost, the principle is rooted in the metaphysical intuition that something cannot come into being from nothing. For to come into existence without a cause of any sort is to come into being from nothing. To suggest that something could just pop into being uncaused out of nothing is to quit doing serious metaphysics and to resort to magic.

Strong words. I'll begin by pointing out the irony of an apologist accusing his opponents of making appeals to magic and move on to the important issue here, Craig is arguing that his first premise is intuitively true. If we deny any of this premise, we aren't doing serious metaphysics.

1.2. Why only universes

From Craig's paper.

The Causal Principle plausibly applies to all of reality, and it is thus metaphysically absurd that the universe should pop into being uncaused out of nothing.
1.3 Experiential Confirmation

And here is where it gets interesting. This should be the evidence we need to leave this whole intuition thing in the dust. Here Craig gives one sentence alone to justify that subheading.

Finally, (1.0) is constantly confirmed in our experience.

The entire rest of the section is dedicated to explaining how, if the first premise is wrong, it is detrimental to the entire scientific endeavor. We'll leave that for later. I just want to point out that there is no actual argument made to defend the thesis he lays out in that first sentence. By all means, go read it for yourself on pages 87-89.

The argument that causation is constantly confirmed in our experience is an interesting one, and true almost all of the time. It is the times when it isn't that we are interested in, and so we will discuss causation and when it breaks down in the next post.

Introducing the Kalam Cosmological Argument.

I have decided to do several posts going into detail on William Lane Craig's version of the Kalam Cosmological Argument (KCA). This post will outline what the argument is, and the most common scholarly objections to date.

First a little background. The KCA is currently very popular with Christian apologists, particularly Evangelicals, but it wasn't always this way. The argument was originally formulated by Islamic scholars within the Kalam tradition, hence the name. It is William Lane Craig that popularized it with Christian audiences in his 1979 book on the subject.

The argument, as Craig originally put it, goes like this:

  1. Everything that begins to exist has a cause of its existence.
  2. The universe began to exist.
  3. Therefore, the universe has a cause of its existence.
  4. Since no scientific explanation (in terms of physical laws) can provide a causal account of the origin of the universe, the cause must be personal (explanation is given in terms of a personal agent)
Craig also provides two other arguments subsumed within these premises.

For premise 2, he argues:
  1. An actual infinite cannot exist.
  2. An infinite temporal regress of events is an actual infinite.
  3. Therefore, an infinite temporal regress of events cannot exist.
Along with:
  1. A collection formed by successive addition cannot be an actual infinite.
  2. The temporal series of past events is a collection formed by successive addition.
  3. Therefore, the temporal series of past events cannot be actually infinite.
There have been oceans of ink spilled over this argument. Most of those oceans focus on premise two, though premise one has also seen its share of comments from the likes of Stephen Hawking.

Craig, along with physicist James D. Sinclair, published the definitive version of the argument in 2009. You can find it in its 101 page glory here. I am going to be relying on that paper for my quotations of Craig in future posts on this topic.

For a very good mapping of Craig's arguments, his main criticisms, and his answers to his critics in his 2009 article, I point you to some of the wonderful work by Luke over at Common Sense Atheism.

The most recent version of the argument that we will be discussing goes as follows (from Luke):

  1. Everything that begins to exist has a cause.
  2. The universe began to exist.
  3. Therefore, the universe has a cause.

But this says nothing about God, so Craig & Sinclair add:

  1. If the universe has a cause, then an uncaused, personal Creator of the universe exists, who sans the universe is beginningless, changeless, immaterial, timeless, spaceless, and enormously powerful.
  2. Therefore, an uncaused, personal Creator of the universe exists, who sans the universe is beginningless, changeless, immaterial, timeless, spaceless, and enormously powerful.
Next, we will look at one particular weakness with the KCA as it currently exists, and why we can't rely on it.