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I don’t know who Rob Sheldon is, but he doesn’t know much about cosmology. He recently was quoted in this post at uncommondescent.com regarding the geometry of the universe. If I lecture cosmology this year, I’ll set this passage as an assignment: find all the mistakes. It gets more wrong than right. I have an article for “Australian Physics” on common questions about cosmology that I’ll post here once it’s out (a fortnight, maybe). In the meantime, I’ll try to clear up a few things.

The discussion of the mathematics of curvature (flat, positive, negative) is about right. It’s when he discusses the universe that things go wrong.

It takes a lot of effort to find any curvature at all, and certainly it is difficult to get good agreement between different types of measurement.

Nope. That’s why it’s called the “concordance model of cosmology” – because the different measurements converge on the same set of cosmological parameters. For example, this plot.

… a “closed” universe that collapses back down to itself …

A common error. In a matter and radiation-only universe, closed implies collapsing. A cosmological constant and/or dark energy changes this: closed vs. open no longer divides collapse vs. expand forever. Here is the plot you’ll need, from John Peacock’s marvellous Cosmological Physics.

… one would like it to have positive curvature to avoid infinities …

Flat and negatively curved universes can be finite. A flat 3-torus, for example, is finite, unbounded and has a flat geometry. Einstein’s general relativity constrains the geometry of the universe but not its topology. Continue Reading »

As I explained in my last post, I’m expecting good things from the upcoming dialogue between Sean Carroll and William Lane Craig. Before discussing the topic, a few comments about debating.

An awful lot of rubbish has been written about counteracting Craig’s diabolical debating; it’s actually pretty simple. When you speak, make a clear argument for a relevant conclusion. After he speaks, target specific premises of his arguments and explain why you think they are unlikely to be true. That’s it. It sounds simple, and it’s been done very effectively, but so many of Craig’s opponents can’t manage it.

Critics have said that Craig unfairly dictates the flow of the debate, keeping a stranglehold on the topic of his choosing. This doesn’t happen when his opponent keeps him busy. Austin Dacey and Keith Parsons are great examples. Craig won’t ignore your case if you make one, and it’s relevant. Give him something to respond to.

If you fail to make a case, Craig will have read your writings and be prepared to both make your own case for you and critique it. He did this to great effect against Rosenberg. If you fail to address his arguments, he will point this out and repeat them. He is justified in doing so because one often hears the refrain that “I’m an atheist because there’s no evidence for God”. To maintain that there is no evidence, one must be able to explain why the supposed evidence isn’t really evidence at all. As an analogy, one cannot reasonably claim that “there is no evidence that human beings walked on the moon” and not attempt to explain the Apollo 11 photographs and videos.

There is no excuse for debating Craig underprepared. You can listen to a debate from the early 1990’s and get most of his arguments. That said, you are better off reading an article rather than responding to a 20 minute summary. It’s best not to raise objections that he has already addressed in print, or even better, raise them in a way that also addresses his response.

Always go for the argument, never the man. If you’ve shown that Craig is mistaken, then it doesn’t much matter how he convinced himself of such falsehoods. Amateur anthropology/psychology/neuroscience – e.g. any sentence beginning with “human beings have a very strong cognitive bias to believe …” – is a waste of time. Just burn down his arguments; don’t toast marshmallows on the embers. Resist Bulverism!

Remember: critiquing is hard. That someone is wrong doesn’t make it easier. Step 1: understand. Step 2: critique. Here are a few resources. Feel free to add more in the comments.

Kalam Cosmological Argument

Contingency (Leibnizian) Argument

  • I think the most comprehensive presentation of Craig’s version of the argument is in his book “Reasonable Faith”. A shorter (and free) introduction is here.

  • Some of the “Questions of the week” shed more light on the philosophical issues that arise: 132, 190, 248, 329.

  • I recommend Alexander Pruss’ article on the Leibnizian argument in the Blackwell Companion to Natural Theology. Craig calls it “a must”, but be aware that it differs from Craig’s version in both content and style. In particular, Pruss defends a more comprehensive version of the principle of sufficient reason.

Fine-Tuning Argument

  • Again, the book “Reasonable Faith” is the best resource. A slightly older presentation is here.

  • Questions of the weeks that address the argument: 49, 63, 161, 313. In particular, Craig’s response to the multiverse, include the Boltzmann Brain problem: 14, 285.

  • For the scientific details of the argument, Craig relies a lot on the work of Robin Collins. Collins’ best presentation of fine-tuning cases is in this book. He presents the argument itself in the Blackwell Companion to Natural Theology. He has an interesting discussion of the implications of the Boltzmann brain problem in this article.

On February 21-22 (2014), Sean Carroll and William Lane Craig will debate at the Greer-Heard Forum, at the New Orleans Baptist Theological Seminary. The topic is “God and Cosmology: The Existence of God in Light of Contemporary Cosmology”. For a number of reasons, I have high hopes for this one. Here’s why.

I (mostly) like the format

We start with a dialogue between the two parties, for 1.5 hours. As a spectator, I prefer the debate format. While a dialogue sounds like a friendly chat rather than a confrontation, in practice it unfairly unfavors the rude and the loud. We are at the mercy of the disciplinary skill of the moderator. However, this one shouldn’t be too bad. Craig will let his opponent talk, and I get the same impression from Carroll.

Given the list of things I’d like them to discuss, as I’ll discuss in future posts, I’m hoping that each party gets an opening statement of at least 20 minutes. They both have a lot to say about this topic, and need the time to present their case thoroughly.

The next day we’re back with 4 speakers, each with an hour that includes responses from Carroll and Craig. That’s a very interesting arrangement and I’m keen to see how it works in practice. The day rounds out with concluding comments from the two debaters.

Good choice of debaters

I’ve listened to a number of William Lane Craig’s debates and the best ones are usually against other philosophers, for this reason. The topic is God, or at least something closely related to the almighty. In any argument for or against the existence of God, at least one of the premises must be metaphysical. So against, say, a scientist, Craig can absorb a lot of the scientific expertise of his opponent and focus on the (often unstated) philosophical assumptions behind their remarks. The debate moves to matters philosophical, which gives Craig the home advantage. Some of Craig’s opponents know less than nothing about philosophy; what they think they know about philosophy is wrong. On the other hand, Craig knows enough of the science that is relevant to his arguments to be able to defend the scientific premises against a philosopher.

Carroll has an undergraduate philosophy minor and as a grad student in astrophysics at Harvard, sat in on courses with John Rawls and Robert Nozick. His blog posts and articles show a familiarity with and respect for philosophical issues. Carroll is close to the ideal opponent for this debate, as he should be able to hold his own on matters philosophical, whilst holding a substantial advantage on matters cosmological.

Good Choice of Respondents

I’m guessing that Craig will defend three of his usual five arguments – the Kalam cosmological argument from the beginning of the universe, the contingency argument, and the design argument from the fine-tuning of the universe for intelligent life. The contingency argument doesn’t rely on any particular scientific theories, so Craig doesn’t need any particular backup on that front. For the Kalam cosmological argument, his scientific case for the premise “the universe has a beginning” has been provided in recent times by James Sinclair. In particular, Craig’s most sophisticated defence of the argument in recent times is in the The Blackwell Companion to Natural Theology, which was co-written with Sinclair. Sinclair is a Warfare Analyst with a masters in cosmology, so his credentials are slightly unorthodox.

Also writing in the The Blackwell Companion to Natural Theology is Robin Collins, a philosopher with a background in physics. He has specialised in the argument from the fine-tuning of the universe for intelligent life. So that gives Craig his backup for his third argument.

Carroll has two philosophers in tow. Alex Rosenberg is a philosopher at Duke University who Craig has debated before, and whose book “The Atheist’s Guide to Reality” was praised by both sides of the debate as seeing rather clearly the consequences of atheism. Tim Maudlin is a philosopher of science at New York University. His book “Philosophy of Physics: Space and Time” is marvellous. He also seems to have taken an interest in the fine-tuning of the universe for intelligent life. (I have a few reservations about his opinions on that topic.)

That’s an interesting line up. I’d gladly hear any of them speak on the topic at hand; all four of them in a row with responses from Carroll and Craig is very promising.

My advice

I think this debate could be uniquely insightful on this important topic. Craig has said an awful lot about cosmology in recent years, and no one has really pressed him on the details. They’ve mostly (though not unreasonably) appealed to cosmological authorities. (For the love of Pete, nobody read out an email from Alex Vilenkin. More on that soon.) Carroll has said a lot about the implications of cosmology for theism, and there are some philosophical niceties to be examined there as well. Stay tuned for parts two, three, and four.

Following my three critiques (one, two, three) of Richard Carrier’s view on the fine-tuning of the universe for intelligent life, we had a back-and-forth in the comments section of his blog. Just as things were getting interesting, Carrier took his ball and went home, saying that any further conversation would be “a waste of anyone’s time”. Sorry, anyone.

I still have questions. Before I forget, I’ll post them here. (I posted them as a comment on his blog but they’re still “awaiting moderation”. I guess he’ll delete them.)

The Main Attraction

What is Carrier’s main argument in response to fine-tuning, in his article “Neither Life nor the Universe Appear Intelligently Designed”? He kept accusing me of misrepresenting him, but never clarified his argument. I’ll have another go. Let,

o = intelligent observers exist
f = a finely-tuned universe exists
b = background information.
NID = a Non-terrestrial Intelligent Designer caused the universe.

We want to calculate the posterior: the probability of NID given what we know. From Carrier’s footnote 29, introduced as the “probability that NID caused the universe”, we can derive (using the odds form of Bayes’ theorem),

\frac{p(NID|f.b)}{p(\sim NID|f.b)}=\frac{p(f|NID.b)}{p(f|\sim NID.b)}\frac{p(NID|b)}{p(\sim NID|b)}   (1)

Carrier argues in footnotes 22 and 23 that,

p(f|o)=1 implies p(f|\sim NID.b)=1,   (2)

because o is part of “established background knowledge” and so part of b. Thus,

\frac{p(NID|f.b)}{p(\sim NID|f.b)}=\frac{p(NID|b)}{p(\sim NID|b)}   (3)

Conclusion: the posterior is be equal to the prior (as seen in footnote 29). Learning f has not changed the probability that NID is true. Fine-tuning is irrelevant to the existence of God.

Question 1: Is the above a correct formalisation of Carrier’s argument? (If anyone has read his essay, comment!) Continue Reading »

I’ve read two of Daniel Dennett’s books, and while I enjoyed them at the time I find myself unable to remember what they were about, what their arguments were, or indeed any memorable passages. Maybe it’s just me, but I remember almost nothing from “Freedom Evolves”.

I’ve just watched one of Dennett’s TED talks, having been pointed there by 3quarksdaily. The title of the talk is “The Illusion of Consciousness”. Maybe I’m being thick, but I after 20 minutes I’m left with this question: what does any of this have to do with consciousness at all, let alone showing it to be an illusion? Before I move on, I should stress that I’m no kind of philosopher of mind or neuroscientist. I’m not even particularly well-read in the popular literature of these fields. Comments, please!

What I’m going to try to do today is to shake your confidence … that you know your own, inner-most mind, that you are, yourselves, authoritative about your own consciousness. …

Somehow we have to explain how, when you put together teams, armies, battalions, of hundreds of millions of little robotic unconscious cells … the result is colour, content, ideas, memories, history. And somehow all that concept [content?] of consciousness is accomplished by the busy activity of those hoards of neurons.

So we’re off to a good start. The hard problem of consciousness is to explain why certain collections of cells become conscious at all. Dennett particularly wants to question whether we really know our own conscious selves. Good. What is his method?

How many of you here, if some smart alec starts telling you how a particular magic trick is done, want to block your ears and say, “I don’t want to know. Don’t take the thrill of it away. I’d rather be mystified. Don’t tell me the answer.” A lot of people feel that way about consciousness, I’ve discovered. I’m sorry if I impose some clarity, some understanding on you. You better leave now if you don’t want to know these tricks.

Method: condescension. He’s going to smug those illusions right out of us.

The example is wrong. I don’t want you to tell me how a magic trick is done for the same reason I don’t want the stranger on the train to lean over and give me crossword answers. It’s a puzzle. The fun is thinking about it yourself. No one says “I don’t want the crossword answers. I just want the mystery of the empty squares.”

Note the implicit ad hominem. Anyone who disagrees with Dennett is weak-minded, a blissful ignoramus. Actually, those who criticised books such a Dennett’s “Consciousness Explained” usually complained that it failed to explain consciousness.

I’m not going to explain it all to you. … You know the sawing the lady in half trick? The philosopher says “I’m going to explain to you how that’s done. You see  – the magician doesn’t really saw the lady in half. He merely makes you think that he does.” How does he do that? “Oh, that’s not my department”.

This is all very amusing, and delivered with a twinkle in the eye. But the message of the metaphor is this: brace yourself for some bald assertion. I’ll tell you what follows from my assumptions, but don’t expect any evidence.

Continue Reading »

I thought I was done with Richard Carrier’s views on the fine-tuning of the universe for intelligent life (Part 1, Part 2). And then someone pointed me to this. It comes in response to an article by William Lane Craig. I’ve critiqued Craig’s views on fine-tuning here and here. The quotes below are from Carrier unless otherwise noted.

[H]e claims “the fundamental constants and quantities of nature must fall into an incomprehensibly narrow life-permitting range,” but that claim has been refuted–by scientists–again and again. We actually do not know that there is only a narrow life-permitting range of possible configurations of the universe. As has been pointed out to Craig by several theoretical physicists (from Krauss to Stenger), he can only get his “narrow range” by varying one single constant and holding all the others fixed, which is simply not how a universe would be randomly selected. When you allow all the constants to vary freely, the number of configurations that are life permitting actually ends up respectably high (between 1 in 8 and 1 in 4: see Victor Stenger’s The Fallacy of Fine-Tuning).

I’ve said an awful lot in response to that paragraph, so let’s just run through the highlights.

  • “Refuted by scientists again and again”. What, in the peer-reviewed scientific literature? I’ve published a review of the scientific literature, 200+ papers, and I can only think of a handful that oppose this conclusion, and piles and piles that support it. Here are some quotes from non-theist scientists. For example, Andrei Linde says: “The existence of an amazingly strong correlation between our own properties and the values of many parameters of our world, such as the masses and charges of electron and proton, the value of the gravitational constant, the amplitude of spontaneous symmetry breaking in the electroweak theory, the value of the vacuum energy, and the dimensionality of our world, is an experimental fact requiring an explanation.” [emphasis added.]

  • “By several theoretical physicists (from Krauss to Stenger)”. I’ve replied to Stenger. I had a chance to talk to Krauss briefly about fine-tuning but I’m still not sure what he thinks. His published work on anthropic matters doesn’t address the more general fine-tuning claim. Also, by saying “from” and “to”, Carrier is trying to give the impression that a great multitude stands with his claim. I’m not even sure if Krauss is with him. I’ve read loads on this subject and only Stenger defends Carrier’s point, and in a popular (ish) level book. On the other hand, Craig can cite Barrow, Carr, Carter, Davies, Deutsch, Ellis, Greene, Guth, Harrison, Hawking, Linde, Page, Penrose, Polkinghorne, Rees, Sandage, Smolin, Susskind, Tegmark, Tipler, Vilenkin, Weinberg, Wheeler, and Wilczek. (See here). With regards to the claim that “the fundamental constants and quantities of nature must fall into an incomprehensibly narrow life-permitting range”, the weight of the peer-reviewed scientific literature is overwhelmingly with Craig. (If you disagree, start citing papers).

  • “He can only get his “narrow range” by varying one single constant”. Wrong. The very thing that got this field started was physicists noting coincidences between a number of constants and the requirements of life. Only a handful of the 200+ scientific papers in this field vary only one variable. Read this.

  • “1 in 8 and 1 in 4: see Victor Stenger”. If Carrier is referring to Stenger’s program MonkeyGod, then he’s kidding himself. That “model” has 8 high school-level equations, 6 of which are wrong. It fails to understand the difference between an experimental range and a possible range, which is fatal to any discussion of fine-tuning. Assumptions are cherry-picked. Crucial constraints and constants are missing. Carrier has previously called MonkeyGod “a serious research product, defended at length in a technical article”. It was published in a philosophical journal of a humanist society, and a popular level book, and would be laughed out of any scientific journal. MonkeyGod is a bad joke.

And even those models are artificially limiting the constants that vary to the constants in our universe, when in fact there can be any number of other constants and variables.

In all the possible universes we have explored, we have found that a tiny fraction would permit the existence of intelligent life. There are other possible universes,that we haven’t explored. This is only relevant if we have some reason to believe that the trend we have observed until now will be miraculously reversed just beyond the horizon of what we have explored. In the absence of such evidence, we are justified in concluding that the possible universes we have explored are typical of all the possible universes. In fact, by beginning in our universe, known to be life-permitting, we have biased our search in favour of finding life-permitting universes. Continue Reading »

Last time, we looked at historian Richard Carrier’s article, “Neither Life nor the Universe Appear Intelligently Designed”. We found someone who preaches Bayes’ theorem but thinks that probabilities are frequencies, says that likelihoods are irrelevant to posteriors, and jettisons his probability principles at his leisure. In this post, we’ll look at his comments on the fine-tuning of the universe for intelligent life. Don’t get your hopes up.

Simulating universes

Here’s Carrier.

Suppose in a thousand years we develop computers capable of simulating the outcome of every possible universe, with every possible arrangement of physical constants, and these simulations tell us which of those universes will produce arrangements that make conscious observers (as an inevitable undesigned by-product). It follows that in none of those universes are the conscious observers intelligently designed (they are merely inevitable by-products), and none of those universes are intelligently designed (they are all of them constructed merely at random). Suppose we then see that conscious observers arise only in one out of every 10^{1,000,000} universes. … Would any of those conscious observers be right in concluding that their universe was intelligently designed to produce them? No. Not even one of them would be.

To see why this argument fails, replace “universe” with “arrangement of metal and plastic” and “conscious observers” with “driveable cars”. Suppose we could simulate the outcome of every possible arrangement of metal and plastic, and these simulations tell us which arrangements produce driveable cars. Does it follow that none of those arrangements could have been designed? Obviously not. This simulation tells us nothing about how actual cars are produced. The fact that we can imagine every possible arrangement of metal and plastic does not mean that every actual car is constructed merely at random. This wouldn’t even follow if cars were in fact constructed by a machine that produced every possible arrangement of metal and plastic, since the machine itself would need to be designed. The driveable cars it inevitably made would be the product of design, albeit via an unusual method.

Note a few leaps that Carrier makes. He leaps from bits in a computer to actual universes that contain conscious observers. He leaps from simulating every possible universe to producing universes “merely at random”. As a cosmological simulator myself, I can safely say that a computer program able to simulate every possible universe would require an awful lot of intelligent design. Carrier also seems to assume that a random process is undesigned. Tell that to these guys. Random number generators are a common feature of intelligently designed computer programs. This argument is an abysmal failure.

How to Fail Logic 101

Carrier goes on … Continue Reading »

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