Andrea Bottaro posted Entry 25 on March 25, 2004 10:22 PM.
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"Of all the gin joints in all the towns in all the world, she walks into mine."
As every film buff knows, that's what Humphrey Bogart glumly says in Casablanca, after his ex-lover (Ingrid Bergman) shows up at his Rick's Café Americaine. Bogart's Rick Blaine is of course justified in his astonishment - it certainly looks like a rather uncanny coincidence. However, most of us in the audience plainly realize that had Bergman chosen another joint, or another town, we'd simply be watching a different movie. In other words, if you are the main character in a movie, chances are you are part of an unusually interesting story: that's a so-called "observation selection" effect.

For reasons that I can't comprehend, however, this basic logic seems to escape a lot of fairly intelligent people, the most recent entrants on the list being astronomer Guillermo Gonzalez and philosopher Jay Richards. Their recently released book "The Privileged Planet" (TPP), argues not only that Earth is uniquely endowed for life forms just like us to appear (an old idea), but that our planet is also just right for those life forms to develop the scientific method, and to apply it to discover the fundamental Laws of the Universe. The series of coincidences behind these simple observations is so amazing, they say, that just a Cosmic Screen-writer could have come up with it.

Predictably, the book (and its spin-off documentary) is being hailed by Intelligent Design advocates as the best thing since, well, their last book and spin-off documentary. The National Review Online, which when ID is concerned seems to quickly shed any semblance of critical sense and journalistic standards, hosts a raving review, complete with tabloid-style bullet points and claims of (post-)Copernican Revolutions. I think all these apologists should be more cautious, as Gonzalez's and Richards' thesis seems to raise more problems for ID than it solves.

To be clear, I do not intend here to review the book or directly address its specific arguments. First of all, I am no astronomer, physicist or philosopher (and unlike many prominent ID advocates, I am loathe to blather about things I do not know enough about). Furthermore, some of these ideas, especially those related to the first part of the argument (the fine-tuned Earth and Universe) have already been addressed in many extensive discussions of TPP's philosophical granddad, the Anthropic Principle, in its Strong and Final iterations (a good starting point about the AP is Nick Bostrom's web site, altough several of its links seem to be broken). Finally, there are already some critiques of the Privileged Planet hypothesis circulating on the web (such as Kyler Kuehn's, summarized in this Powerpoint presentation), which I am sure will soon be developed more formally and published, now that the book is out.

I want to talk instead about the implications of TPP for ID advocacy in general. The thing that truly puzzles me the most is that the argument for the Earth's suitability for discovery goes smack against much of the ID rhetoric against "naturalistic" science. "Challenging the reigning ideology of materialistic naturalism" (as the jacket of Dembski's "Mere Creation" promises) has been one of the fundamental principles of ID since its founding. From philosopher Plantinga to ID's legal-eagle Beckwith, ID has consistently attacked science's methodological naturalism (the use of empirical evidence about natural causes to explain natural phenomena) as a front for, or even the cause of, philosophical naturalism (the metaphysical claim that natural causes are all there is) .

Methodological naturalism and the scientific method developed and flourished because they proved much more successful at interpreting natural phenomena than the alternative approaches, leading to all the amazing discoveries Gonzalez and Richards are so justifiably enthused by. In other words, the scientific method that TPP claims the intelligent inhabitants of a purposefully designed Earth were meant to ultimately develop and so spectacularly apply, is the result of the application of methodological naturalism. Without methodological naturalism, there would have been no science as we know it, and very arguably no Privileged Planet hypothesis.

So, is the scientific method good or bad? If it is bad, why has the Designer designed the Universe to fool us into using it? If naturalistic science is a mistake, and its accomplishments mostly illusory, the supposed Earth's "privilege" would in fact just be a big joke, on us. On the other hand, if the scientific method is good and useful, and was even pre-ordained by the Designer, why should we drop it now in favor of non-naturalistic ID "theory"?

Perhaps, one could say, it was also pre-ordained that scientific naturalism would run its course, and be replaced at this historical juncture by non-naturalistic ID, so that we could discern the Grand Plan. That sounds rather expedient, of course, but even taking it at face value, if the goal was for us to discover a Grand Plan, what better way to do that than an Aristotelian Universe of which the Earth is the proud geometrical center? Why the charade?

ID advocates usually dodge this kind of questions by quickly declaring that the intentions of the Designer are outside the realm of investigation, and gladly drop the subject. But this excuse would certainly not cut it in this case, since TPP itself is, strictly speaking, one long argument about the intentions of the Designer!

Finally, there is possibly a strategic issue at play here as well. ID advocates have long insisted that ID is not inherently religious because the Intelligence it purports to be capable of detecting could be a naturalistic one (eg, aliens). This would supposedly allow ID to leapfrog over the many constitutional hurdles against the teaching of religion in schools. However, any hypothesis about Planetary and/or Universal Destiny clearly makes this position untenable - this Designer can only be (a) God. It seems to me that, should ID fully and officially embrace TPP's thesis, its Establishment Clause strategy goes out the window, and with it its only chance to mold young minds, before their critical sense develops.

That's a problem, but as Bogart would say, "everybody in Casablanca has problems".

Comment #191

Posted by John Wilkins on March 25, 2004 07:23 PM (e) (s)

This phenomenal a posteriori effect I hereby dub the Casablanca Effect - we see it because it happened, and had it not happened, we’d not see it. What are the odds?

Comment #194

Posted by Ed Brayton on March 25, 2004 07:45 PM (e) (s)


Excellent essay, and I’d point out one additional inconsistency. Howard Van Till and Ken Miller would make this argument. The ID advocates want us to believe that the universe was perfectly designed for life to exist and flourish on the earth, but not so perfectly designed that God didn’t have to intervene in the history of life to insure that life existed on earth. If the universe was really perfectly designed for life to exist and flourish on earth, it would be what Howard Van Till calls a “fully gifted creation”, not one in which God still had to intervene in order to make sure that life got started on earth.

Comment #200

Posted by John Mattson on March 25, 2004 08:14 PM (e) (s)

If Ilsa Lund doesn’t walk through the door, there is no movie. Rick plus December 1941 plus Ilsa = Rick joining the fight. Sine qua non. However, since it’s a “story,” it’s easy to imagine a “world”/movie where Ilsa doesn’t walk through the door and (all other elements being unchanged) Rick therefore does NOT act, Laslo is killed and the Germans win. This is reminiscent of the famous original Star Trek episode (written by Harlan Ellison), in which McCoy travels back to 1930s Earth, saves a social worker (Joan Collins!) who is supposed to die, and the resulting domino effect leads to Germany winning the war and, finally the non-existence of the Federation and the Enterprise. (never mind that no loop is created; i.e. this DOESN’T lead to McCoy not existing to go back in time to save Joan Collins, etc.). The “series of amazing coincidences” argument reminds me of the old science fiction device (a la Larry Niven’s “All the Myriad Ways”) by which every time a decision is made in the universe, multiple universes spring up, one for each of the possibilities that arise, so that all the myriad variables are played out somewhere. Naturally, there would be one where our special set of circumstances lines up (this world we live in, of course); but, as someone has pointed out — Hawking? I forget — it’s possible using such a universe “decision tree” to imagine a universe just like ours where the universe is designed to deceive us so all our science is wrong, but APPEARS to be right. Of course, it’s worth noting that such a design for the universe is remarkably unintelligent, since there is no preference for — or even a criteria for choosing — one decision (much less species or planet) over another.

Comment #205

Posted by Joe Barranco on March 25, 2004 09:00 PM (e) (s)

Excellent site… I just earned my PhD in
Astrophysics from Berkeley last month, and I’m now a NSF Postdoctoral Fellow at the Kavli Institute for Theoretical Physics in Santa Barbara… my dissertation was on the fluid dynamics of protoplanetary disks… the disks of gas and dust out of which planets form…
I think I’ll pick up the book this weekend, and have a go at reading/critiquing it this weekend… And in the future, I offer up
my services as as an astro-type to complement all the bio-types here… Peace.

Comment #208

Posted by Nick on March 25, 2004 10:26 PM (e) (s)

The funny thing about anthropic-style arguments is that they really *depend* upon evolution in order to have any traction at all. The fundamental physical constants that “ensure” that the Universe has the right balance of hydrogen and helium and a long lifespan that ensures the immense amount of time needed for several generations of stellar evolution necessary to build up heavy elements, the arrangement of the solar system such that we are (kind of) protected from asteroid strikes, etc. — all of this is important only if the development of complex life is a very slow, very natural process.

If life, bacterial flagella, humans, etc. were “poofed” into existence by an Intelligent Designer, all of the above careful set-up is pointless. The Universe could be shaped like a solar-system-sized taco, the earth could be flat, and the moon literally made of green cheese, if life was to be created in a “puff of smoke”.

The idea that the Universe was oh-so-carefully designed to support life, but that life couldn’t come about without extranatural intervention, is like claiming someone would buy Kansas in order to have a place to put their terranium (and this mathematically *understates* the absurdity of the situation by many orders of magnitude).

Comment #209

Posted by Loren Petrich on March 25, 2004 10:46 PM (e) (s)

Two holes in the “Privileged Planet” hypothesis:

* Natural selection. The Earth is the only planet in the Solar System that can allow us to exist relatively unprotected, etc. - making the PP hypothesis something like Dr. Pangloss’s argument that we have noses so we can wear glasses, and that our legs are shaped so we can wear pants.

* Is the Earth really the best possible place for us? The Sun is slowly getting brighter, and the carbon-dioxide-weathering geochemical thermostat may shut down in a billion years from now as the equilibrium amount of CO2 goes down to zero. Meaning no more plants. Also, the Earth’s water supply may be destroyed by its hydrogen evaporating into space at that time.

So the Earth might have been better off a little farther from the Sun, and the Sun itself may have been more convenient for us by being a little less massive — and therefore slower-evolving.

Comment #210

Posted by Greg Jorgensen on March 25, 2004 11:40 PM (e) (s)

William Dembski already posted a glowing review of this book on

Comment #217

Posted by Matthew on March 26, 2004 02:48 AM (e) (s)

The best image to refute TPP or similar worldviews is one that the late Douglas Adams came up with. He liked to say this was like some small water puddle, marvelling at how the ground was so wonderfully adapted to its shape!

Comment #218

Posted by Sarah Berel-Harrop on March 26, 2004 04:25 AM (e) (s)

“If the universe was really perfectly designed for life to exist and flourish on earth, it would be what Howard Van Till calls a “fully gifted creation”, not one in which God still had to intervene in order to make sure that life got started on earth.”

He also calls ID and other forms of episodic
creation “the celebration of gifts withheld”.

Comment #220

Posted by Casey Lippmeier on March 26, 2004 05:04 AM (e) (s)


Nice blog you have here. Why are we still calling it the “Theroy of Evolution”? Perhaps you could use the rising popularity of this blog to promote the idea of the “Law of Evolution”. I’m a molecular biologist. I have made thousands of observations explained by this so-called “theory”. Can we please move on and properly formalize evolution as a law? I expect that the only reason why we haven’t done so already is because of creationist opposition.

If thermodynamics had these troubles where would we be?

Comment #221

Posted by DS on March 26, 2004 05:11 AM (e) (s)

Look it’s simple.

The ‘fact’ that the universe and/or the earth are perfectly configured to allow life to arise and thrive naturally is evidence for ID…

Meanwhile, the ‘fact’ that life is far too complex to arise naturally is evidence for…ID.

Any questions?


Comment #223

Posted by Ed Brayton on March 26, 2004 06:37 AM (e) (s)


By George, I think he’s got it!

Comment #228

Posted by cba on March 26, 2004 09:13 AM (e) (s)

Nice to see a blog with a biological theme.

RE: TPP hypothesis: It reminds me of the uproar over extrasolar planets. The ID side was against finding extrasolar planets & thus remove Earth’s exclusivity in the universal design.

Chances are (and probability plays a big role in our universe) there will be many more extrasolar planets than the 50+ already discovered. Our situation is not so special when you consider the mind-boggling size of universe.

Life developed on Earth because it could. Given the right conditions, life could arise anywhere.


Comment #240

Posted by Steve Reuland on March 26, 2004 01:14 PM (e) (s)

The TPP argument can be summed up in two words: Selection Bias.

It is a matter of necessity that the scientific discoveries we’ve made to this date, out of set of all possible discoveries, are the ones that are “easy” to discover. If they were too hard to discover, then we wouldn’t have discovered them. Pretty simple.

One can of course come up with dozens of examples of how stuff in this universe does not seem conducive to discovery. Proteins are my favorite example, since I work with them. They’re tiny, unstable, dynamic, and their structure is very hard to deduce. They are, in general, a pain to work with. But I suspect that Gonzales and Richards would say that their ease of discovery was precluded by a more important purpose, namely their ability to function in living things as they were “designed” to function. Okay, fair enough. But that just means that the examples which are easy to discover are being subjected to selection bias, since you have a reason to exclude those things which are not.

Comment #266

Posted by Jan Haugland on March 26, 2004 06:04 PM (e) (s)

DS: Great short argument. I have to remember it.

Personally, I think the universe is created to be uniquely habitable to rocks. There are, after all, lots more rocks than lifeforms.

Comment #268

Posted by Andrea Bottaro on March 26, 2004 06:38 PM (e) (s)

To be fair, the Anthropic Principle arguments present several interesting logical and epistemological aspects. I don’t want to immediately break my own rule not to talk about things I don’t know much about, so I earnestly suggest people check out Nick Bostrom’s web page about the AP (especially, if you have time, the excerpts from his book).

Also, note that the issue of observation selection cuts both ways: just as we can’t say life on Earth is too improbable to just have happened, we can’t say that life must happen quite easily once Earth-like conditions are met, based only on the fact that it happened here. That would be equivalent to Rick Blaine’s assuming, based on his experience, that having an affair with Ingrid Bergman must be quite commonplace after all!

Comment #303

Posted by Loren Petrich on March 27, 2004 10:03 AM (e) (s)

I agree that it’s unreasonable to infer that origin of life on Earthlike planets is “easy”.

The Earth has most likely had only one OOL event with present-day survivors. I’m sure that if there was another one with survivors, then those organisms would have some distinctive biochemical features, like genetic material that cannot be amplified or sequenced with typical lab techniques.

Comment #341

Posted by Thomas Dent on March 28, 2004 09:54 AM (e) (s)

Can we try to keep the TLA’s (three letter abbreviations) to a minimum? By “the Earth has most likely had only one OOL event with present-day survivors” you mean “The life that we see on Earth originated in a unique event”.

Isn’t this obvious anyway? Once life has originated, it will quickly monopolise the resources that was previously available for life-origination, and henceforth there will be no space left for another truly independent origination. In a competition for resources between two independently originated and incompatible types of life, it’s a virtual certainty that one of them will be wiped out quite quickly. If they’re not incompatible, then they may coevolve and the end result may (may!) be indistinguishable from a single origin. But note that, since the second “origin” happened after the world had been colonized by the first form of life, it would be a rather curious event which it would be difficult to describe as a real “origin” rather than a development or evolution of the previous form of life.

Unless, of course, the second origin took place in an environment that was fatally hostile to the first. Archaebacteria that flourish in hot springs with odd chemistry might be considered a candidate, unless someone has found a convincing evolutionary tree which includes them.

Comment #344

Posted by Loren Petrich on March 28, 2004 10:52 AM (e) (s)

I don’t see how that’s supposed to be self-evident. The present-day biota contains an enormous number of species that coexist with each other, and the same thing could happen among separately-originating organisms.

Thus, an organism could emerge near the North Pole and another one soon after near the South Pole, with little chance of conflict. But there will still be a limited window of opportunity for the South-Pole organism to emerge in, because the North Pole’s one can proliferate and spread, eventually reaching the South Pole.

Comment #367

Posted by Thomas Nephew on March 28, 2004 07:57 PM (e) (s)

I think Kieran Healy has made a similar point about other unwarranted generalizations, “It’s called sampling on the dependent variable.” He closes:
Coming up soon, a study that attempts to explain why so many of the closets I open are full of my clothes.
(via Electrolite).

Comment #6322

Posted by Great White Wonder on August 11, 2004 03:57 PM (e) (s)

Loren and Thomas, I’m not sure what you’re getting at. As far as I’m concerned, there is no reason to believe that new life forms aren’t constantly being created at various sites on planet Earth.

The problem is that we have no way of continually monitoring their creation and existence.

Can you tell me how would go about deteriming that new (e.g., non-nucleic acid based) microbial life forms aren’t arising at or near any of several oceanic vents and/or geothermic springs and the quickly being eaten by the bacteria which occupy those niches presently?

Comment #6323

Posted by Great White Wonder on August 11, 2004 04:00 PM (e) (s)

Good God, let me try that again:

Can you tell me how one would go about determining that new (e.g., non-nucleic acid based) microbial life forms aren’t periodically arising at or near any of several oceanic vents and/or geothermic springs, said life forms quickly being eaten into extinction by the DNA-based micro-organisms which presently occupy those niches?

This is what happens when you have two hotdogs for lunch.

Comment #7611

Posted by Bob Maurus on September 11, 2004 08:18 PM (e) (s)

They’re coming (or is that cumming?) out of the woodwork. C’mon guys, police your site.