Welcome to the club

They haven't discovered an Earth-like planet yet, but astronomers are getting closer every year. 55 Cancri A, the larger member of a nearby binary star in Cancer (41 light-years away), now has a confirmed five planets, including a large outer giant, as well as four inner medium-sized giants. The system might have Earth-like (rocky) planets with thin atmospheres, but those still lie below the threshold of detectability. It's also possible that these planets have Earth-like moons (bigger versions of Saturn's Titan) with atmospheres. OTOH, keep warm oceans in mind too, if you're looking for life.

The parent star is 0.61 as luminous as our Sun. Thus the distance for Earth-equivalent light flux from 55 Cancri A is (0.61)^1/2 AU = 0.78 AU, roughly the Sun-Venus distance (0.72 AU). (One astronomical unit, or AU, is the Sun-Earth distance, 93 million miles = 150 million km.) One of the 55 Cancri A planets is about that close to the star, so a rocky moon is a contender for Earth-like conditions.

The anthropic principle: The final word

My final posting - I swear! - on this subject was inspired by this sentence from a book review I read recently: "science is the art of answering the answerable, not imagining the imaginable." Exactly. Anyone who absorbs and understands this dictum will also understand what's wrong with the anthropic principle.

Teleology: The afterparty

Maybe this posting was the real point of my earlier musings on teleology and the anthropic principle ... :=)

A friend asked why "intelligent design" - what has that got to do with purpose? I mentioned that Spinoza believed in a universe with design but no purpose. A better phrase than "intelligent design" would thus be "purposive design" - that captures the nature of the controversy better.

BTW, you might wonder what happened to Aristotle's four-fold causality after that Scientific Revolution thingie 300 years ago or so. Scientists have mostly come to rely on Aristotle's second and third categories. The material or efficient cause is the physical entity in the objective world. The formal cause is the abstract law, the ghost of Plato's Ideas, but grasped in our minds. Formal causes are the mind's form of comprehension; they're in the mind, but not just in the mind. First causes have been reduced to "initial conditions." Final causes have been rendered suspect, although for any living entity, especially conscious ones with intentionality, they're unavoidable. Locke has a sensible discussion of these issues, in somewhat different and slighty archaic language, that hasn't really been improved upon in the last three centuries.

Locke was also the first to state the basic duality of Western thought in a clearly modern form. From Plato to Descartes, it was the duality of mind and body, or body and soul. Locke was the first to recast this as a duality of subject and object. Again, the issue hasn't really moved since then, although Hume and Kant did a lot to reformulate the issue in terms familiar today.

Afterthoughts: Teleology and the anthropic principle

First, an apology: I've written before on the anthropic principle (AP), but the AP is used in widely varying senses, and my earlier postings didn't meet this issue directly. Nowadays, you see the AP popping up in two very different ways in two very different contexts - in the evolution/intelligent design controversy and in string theory. I've mainly posted about the latter case, but the former is better-known and more interesting.

There is a sense of the AP (the strong form) which implies teleology or final (purposive) causation. Stated in modern language, teleology or purposive causality is a generalization of the intentionality inherent in living and especially consciousness entities. It need not involve human-like consciousness. The key difference between final causation and reductionism is that reductionism posits a fundamental causality that is purely past-conditioned and purely forward-looking; it contains no feedback. Purposive causality requires "feedback loops" and implies some kind of circularity in the causal sequence. That living and conscious entities exhibit such circular feedback in their purposive behavior is not in dispute; the question is whether such causality is secondary, or if non-living entities and possibly the universe as a whole exhibit such feedback. If the latter, then teleology is fundamental to the universe; if not, it is a secondary phenomenon piggy-backing on a fundamentally causal but "blind" non-purposive universe.

A popular example of teleological reasoning is the "argument from design" or Intelligent Design (ID). But the AP is simpler and more general than that, and it doesn't have to be supernatural or theistic. The classic example in Western philosophy is Aristotle's four-fold causality (first, material or efficient, formal, and final); his system is neither theistic nor supernatural. Modern science started in the 17th century, attended by a philosophical revolution brought off by Descartes, Spinoza, and Locke. The agnostic or negative position of these early modern thinkers on final causality was crucial in the birth of modern scientific thinking. Spinoza's position was the most radical and consistent: he believed in a universe with design but without purpose. His militant monism (one Substance with many Modes) and unqualified belief in blind determinism have the appeal of consistency, but beg the question: purposive causality is inescapable for understanding living entities, and even more so, conscious ones. Descartes' solution was an extreme dualism: human consciousness (res cogitans = thinking stuff) is a supernatural soul; everything else (including our bodies and other animals) is a blind machine (res extensa = matter-energy in spacetime). Unfortunately, this solution, still very much with us as a pratical rule of thumb, has gradually been knocked down by modern biology, psychology, and medicine. Aristotle's unified treatment of all forms of biological teleology is theoretically superior. At the end of the 17th century, Locke had what, for modern science, has amounted to the final word on this question, which has seen no real improvement since. Agnostic on the role of teleology in the universe at large, Locke admitted that final causes are inescapable for understanding any kind of life. However, Locke also believed that "G-d could make matter think" and held out the hope that Descartes' dualism could ultimately be overcome. Hume in the 18th century attacked intelligent design and purposive causality, but from a quite different direction, casting doubt on causality and objective knowledge altogether. Such skepticism leads, not to modern science, but in a nihilistic direction first explored by Nietzsche in the late 19th century; it needn't detain us here.

What's the bottom line? The rejection or suspicious treatment of final causes is not a result of modern science, but an assumption. Modern science has made far more progress on "what" and "how" questions than on "why?". That fact alone justifies this approach, but it leaves unanswered the "why" questions that everyone ever born has thought of. The status of final causality remains elusive: is it a fundamental metaphysical category or a secondary of non-purposive causality?

This type of AP makes no sense in a Newtonian world, which is just such a world of blind determinism, driven by causal laws and conditioned only by past events. In modern physics, with quantum mechanics, non-equilibrium thermodynamics, and modern cosmology, such questions can be asked again, but we still lack definitive answers. Obviously, a teleology acceptable today would be very different from Aristotle's, since our knowledge of physical and biological mechanisms is broader and deeper than his was. It would be more abstract and simpler, and would hinge essentially on information or entropy, treated as a co-equal to spacetime and matter-energy. Information is inherently selective; it selects some of the world as "signal" and rejects the rest as "noise." Such selectivity is visible everywhere in the living world, from nutrition and waste elimination (eat this, flush that), to consciousness (attention to this, ignoring of that), to evolution by selectional mechanisms (this fits, that doesn't).

Philosopher Thomas Nagel recently penned a penetrating treatment of final causation in the form of a review of Richard Dawkins' new book, The God Delusion (requires subscription). By way of talking about Darwinist-selectional theories of biological evolution, Nagel takes Dawkins and others to task for overstating their case: Darwin's theory explains the origin of species, but not the origin of life - it doesn't and can't answer such a question. (Amusingly, Dawkins has to fall back on the hand-waving of the weak AP, invoking billions and billions of planets, instead of billions and billions of universes - explaining nothing - see below.) And Darwin's theory is a non-teleological (although not deterministic) theory - all modern scientific theories are: by assumption, not because they prove final causes invalid.

Since the 17th century, purposive causality has lived in a limbo of "parascience"; if it involves super- or "extra"-naturalism, it falls outside science altogether. The best-known case in recent years is the ID movement, which is attempting to re-introduce strong teleology into biology, a purposive causality set up by a human-like designer. In practice, many invocations of final causes are scientifically redundant, unfalsifiable, or empty. That fact is the (generally sound) basis for attacking the ID movement as pseudo-science. And many attempts to import ID theory into biology teaching are much cruder than that, just thinly veiled forms of creation "science," an obvious anti-science, as it rejects not just Darwinian selectional theories, but the whole framework of modern cosmology, geology, biochemistry, and genetics.

But in a final irony, the "other" AP controversy raging right now - about the weak form of anthropic reasoning invoked by string theorists - shows the AP in a much worse and far more objectionable light than the ID controversy. This non-teleological form of the AP proposes an infinity of unobservable universes, with no method to enumerate them, and offers no explanatory power whatever. It gives up on the project of modern science, seeking unity among observable phenomena: matter and energy, space and time, living species as descended from a common ancestor and sharing the same biochemistry, etc. The weak AP is a flight from scientific reason, driven by blind clinging to string theory. That theory isn't a real theory anyway, only an unlikely conjecture, and its solutions are more conjecture. As astrophysicists devise thought-universes with slightly different physical laws that can also support life as we know it, the reasoning behind this form of the AP falls apart. Its sole appeal is to people who believe in string theory for other reasons anyway (and bad reasons at that). This weak, multiverse AP is truly "millennial madness." It widens the already large chasm between string theorists and the rest of science and pushes string theory even further down the road of becoming a self-validating cult. And it makes creationism and ID look good by comparison - almost like real science.

Mon Dieu! Postscript on the social contract, and bagels ...

In my posting on why America is not an empire, I inexplicably forgot a fourth critical theorist of the social contract, Spinoza. How could I? He came after Hobbes and Descartes, and his influence on Locke's political and metaphysical theory is obvious. And from Locke to the American founders is but a short step ....

On a totally unrelated note, Trader Joe's carries my favorite brand of bagels, the Bagel Spinoza: It Bagels the Mind. I hope our blog here is exactly what the Bagel Spinoza is: chewy, filling - and really delicious toasted with peanut butter. I wonder what Spinoza himself would have thought.

POSTSCRIPT to postscript: Friday's Wall Street Journal has a nice column by science columnist Sharon Begley on the dubious nature of the anthropic principle. Nice to see outsiders noticing and joining in the fray - on the side of science and reason.

Unfortunately, it requires a subscription. But here are two key grafs:

For years, many scientists viewed anthropic reasoning as "the last refuge of scoundrels," says cosmologist Lawrence Krauss of Case Western Reserve University. "It was what you resorted to when you couldn't think of other explanations. But science has always tried to explain why the universe is the way it is. With the anthropic principle you're saying you can't explain why the fundamental constants have the values they do. It's giving up before you really get started."

Exactly. (Krauss has a new book out, Hiding in the Mirror, that discusses the anthropic controversy in his larger exposition of the higher-dimension concept.) And a recent "what-if?" thought-experiment paper provides a striking counterexample to anthropic reasoning and shines light on why life might happen under a range of conditions:

The anthropic principle was further undermined when scientists calculated what would happen if the universe lost one of its forces. There are four: gravity and electromagnetism, plus the strong force and weak force that act only at the subatomic level. The physicists erased the weak force and adjusted other physical parameters (all done mathematically), they reported in August in Physical Review D. Their calculations showed that the resulting pseudouniverse still made atoms, galaxies and stars that burned and cooked up elements like those in living beings, says Graham Kribs of the University of Oregon, Eugene.

Here are the preprint and published versions of that paper.

The anthropic principle and why it's not science

The anthropic principle (AP) has a number of forms and variants, but in essence, it connects the overall form and evolution of the universe with the existence of life, the existence of intelligent life, and/or with the existence of us. Stated as an empirical fact, we are here, and all the preconditions for our existence obviously place a constraint on theories we might invent to explain the universe. This version of the AP seems like an empty truism, but, like all truisms, it is true. The critical point is that such a meaningful principle is a statement about theories or explanations, not about universes. Then at least, the principle is applied in a way that be verified or falsified. Falsifiability is critical: only if your theory can be proven wrong, can you really be sure that it's right.

Starting in the 1970s, a different and nonscientific form of the AP gained popularity in some quarters as a statement about possible universes, rather than theories. One form, vaguely theistic or at least teleological, states that the universe takes on the form it does so that we can be here. Another form, recently popular among string theorists unable to sort through the apparently very large or even infinite number of possible string theories, states that every string theory is realized in some (unobservable) universe, a small piece of a multiverse. Yet another form posits the existence of new universes evolving from old ones and "selected" by the presence of life.

A number of well-known scientists have tried to claim successfully using anthropic reasoning to arrive at nontrivial conclusions, but none of the examples presented really do that. They use some general property of the cosmos (the presence of carbon, the age of the universe, etc.) to arrive at these conclusions, and none of them require life, much less intelligent life, as a necessary assumption. The originators of the anthropic principle had more explicitly teleological or theological goals in mind, and they were at least honest about the role that religious faith or teleology played in their thinking. (Teleology might prove correct, after all - we don't know enough now to say.) The most recent version is driven by another faith, faith in string theory. The requirement that string theory "must" be right, combined with the failure to produce any complete, consistent, and predictive string theories, has led theoretical physicists to this impasse.

Some have even claimed that we must accept anthropic reasoning or be doomed to accepting Intelligent Design (ID) theory. This is strictly a tempest in a teapot: ID is a type of AP reasoning and, like all such anthropic thinking, has no place in science. We have no alternative universes to compare ours to, so the endeavor is futile.

Besides the lack of observability, a more subtle problem invalidates the AP. Lacking a complete theory that could specify and enumerate possible universes, we have no way of identifying and counting what these universes could be. As mathematicians say, we lack a "measure on the space" of possibilities. Our universe could be one of a large number of random possibilities. ("Random" means: all possibilities are equally likely.) But we don't know the possibilities - we have no non-repetitive and exhaustive list, and no way to assign probabilities. No one knows whether our universe is "likely," or even what that would mean.

It's a sign of how misguided AP advocates are when you consider that, in various forms, it's used by religious fundamentalists, teleological types, and secular academic physicists, all to rescue their respective pet theories from being "not even wrong." The fact of our existence tells you that the Universe has to have a certain age, a certain structure, and the presence of life on one planet that we know of. Any theory not compatible with these facts is ruled out - that's it. No multiverses, no alternate realities, and so on. Whether it proves the existence of G-d is not something rationally decidable. That's why religion involves faith.

(I'm not arguing here against religious faith - humans couldn't live without faith in something: faith in G-d, faith in the future, faith in reason, and so on. I'm just saying it's not definitive and precise knowledge based on experience, which is, after all, what science is about.)

In brief, appeal to the AP and multiverses is not science. We know for sure what we know about the world based on the evidence of the senses and the reasoning based on that evidence. Although scientists use technical and specialized concepts and instruments to pursue knowledge, at the end of the day, they're operating with the same framework as everyone else. If the anthropic principle is about possible universes, we've left the realm of science for speculative metaphyiscs, theology, or science fiction.

Why is this happening?

The current invocation of the anthropic principle is a desperate fad among string theorists to evade the fact that no unique string theory has turned up, and there are no mathematical demonstrations of a unique or even set of realistic solutions to these non-existent "theories." Of all possible theories, they say, all are real, "somewhere". This is nonsense. Any outsider would have to rub his eyes in astonishment to see respected and talented scientific figures playing such games.

POSTSCRIPT: The deadend failure of string theory, what most theorists have devoted the last generation of theoretical physics to, drives this latest outbreak of anthropic lunacy. Theorists want to continue believing in it, even though it's obviously going nowhere. A crisp and illuminating new book by Lee Smolin (himself a quantum gravity theorist) politely but decisively dismantles string theory claims and explains not only what's gone wrong in physics, but why classical scientific self-correction mechanisms have been short-circuited in the postmodern university. I'll discuss Smolin's book in an upcoming posting.

Cool books 2b

Apropos this earlier posting, I just had a good look at another new anti-string book, Peter Woit's Not Even Wrong. Woit shows how string theory isn't even a theory, just a series of conjectures about fundamental forces and matter that have never been assembled into a coherent dynamical system, not to speak of being mathematically solved and subject to decisive tests. Thus, it's "not even wrong," since we have no way of knowing.

Woit's book is a concise telling of how fundamental physics has gone astray in the last generation. He recounts the rise of string theory from a series of obscure conjectural arguments and ideas in the 1970s, how it captured theorists' imaginations in the 1980s, and its later, strange persistence in the face of the increasingly obvious reality that it's not science. Woit winds up with the recent desperate maneuvers by string practioners. String "theory" proposes to replace quantum fields (defined at single points of space and time) with quantum extended objects: in 1-D = strings, in more dimensions = "branes," short for membranes, the 2-D analogue of strings. Without a coherent dynamics, there's nothing to solve -- the so-called "solutions" have themselves never been other than conjectures. In particular, there's no sign of a unique vacuum, or ground state (the most stable state = state of lowest energy). Without that, there's no way to make contact with observation.

The most absurd attempts to cut the Gordian knot of a mind-bogglingly large number of degenerate vacua (ground states with the same energy) appeal to the anthropic principle. (See my earlier posting too.) In a short, devastating chapter, Woit makes mincemeat of the anthropic enterprise: untestable, unprovable, science fiction, really. Either truism or empty proposition, anthropic reasoning leads to multiverses dressed up with a lot of hugger-mugger about Darwinism -- all nonsense: there's no selectional principle and, without a theory to count the various universes and assign them probabilities (no "measure," as mathematicians say), no way to know if our universe is likely or not. The anthropic principle should be banished from physics, and physicists should get back to work on stuff you can observe, test, and measure.

Many theorists defend string theory by pointing to important contributions it has made to mathematical physics. But string theory has contributed essentially nothing new. Draw up an intellectual balance sheet. String theory takes a lot from previous ideas: the Standard Model, with its trio of strong, weak, and electromagnetic forces, backed by gauge and chiral symmetries and general covariance (general relativity) -- a great, largely unsung achievement -- and speculative ideas such as supersymmetry, symmetry breaking, higher dimesions, orbifolds, and non-trivial topologies. It might be said to have contributed something to our understanding of quantum gravity, but even that is questionable. The few specific, meaty results of string theory either rely on conformal, gauge, and supersymmetric quantum field theories or make use of semi-classical arguments that any quantum theory must satisfy to agree with general relativity in the classical limit.

String theory might be best defined as a parascientific cult centered on Princeton and the guru figure of Ed Witten. Woit's book has fine thumbnail sketches of main string theorists, including an extended discussion of Witten. These are all smart, nominally sane people. How did they get sucked into this, why have they persisted for so long, and why have so many students and researchers gotten sucked in as well?

The roots of this debacle lie in the special position of high-energy physics as a science after World War II -- it received a lot of government money and intellectual prestige, accompanied by two+ generations of genuine breakthroughs, leading to the grand synthesis of the Standard Model. Unfortunately, at the highest energies, accelerators have become very expensive and take decades to build. Theory now operates in a void of evidence. Some have jokingly or angrily compared it to post-modernism in the humanities or to "faith-based" approaches like Intelligent Design. But it's really not a joke: string "theory" is not a theory at all. The most frustrating aspect is the snowjob that the string establishment has done on everyone else.

The real progress in fundamental physics today is being made through astrophysics and cosmology. Here data is pouring in from new observational platforms. Theories are being tested and slaughtered by data, leaving only a few standing. That's how real science works. It's patently false to argue, as some have, that string theory marks the "end of science." Plenty of good science is being done as I write this. It's just the end of the line for a certain type of academic theoretical physics, at least as we've known it for a generation. It's not the end of science as such.

Related thoughts from Burt Richter, emeritus director of Stanford Linear Accelerator Center.

Cool books 2

In keeping up with science, I've also recently re-read Lee Smolin's two quantum gravity-inspired books, The Life of the Cosmos and Three Roads to Quantum Gravity. Among specialists, these are controversial topics. Smolin does a fine job of explaining the key concepts and the agonizingly slow progress of unifying the very small (quantum) with the very large (gravity/general relativity/cosmology), including (a) string theory, (b) canonical quantum gravity, and (c) black hole information theory. He proposes a mind-bending multiverse picture where life and consciousness play a critical role in sorting out viable universes. It's speculative metaphysics and no more scientific or convincing than other such multiverse ideas. But Smolin's version is better thought out and argued than the others. He does indulge in too much groovy-sounding postmodernism -- I guess he wants his book to sound hip. But po-mo is anti-intellectual poison. A serious thinker like Smolin should know better.

A critical concept in the "multiverse" debate is the "Copernican principle," which requires that any particular place or time or situation in the cosmos not be "special" in some suitably defined sense. The "multiverse" extends the Copernican principle to multiple universes, not just multiple solar systems or galaxies. The problem is that the Copernican principle isn't a scientific principle like the "principle of relativity" or "energy conservation." These are precisely formulated concepts carefully tested under controlled conditions and confirmed by all observations. OTOH, the Copernican "principle" is really nothing more than a philosophical prejudice (one Copernicus is not even responsible for). There are good reasons to think that it's not all that, especially when it comes to the evolution of complex life. The universality of physics and (with some qualifications) chemistry is an established fact. Not so for biology. If we abandon serious standards for science in favor of philosophical enthusiasms, what we have is not science, but science fiction.

Smolin is coming out with a new book in September, about the failure of string theory and how fundamental physics (the search for a complete and consistent theory of forces and matter) has lost its way. More such books are starting to appear -- they're overdue in my opinion. A lot of money and talent has been sunk into string theory in the last 20+ years, accompanied by a lot of gaga hype, with no more than modest results.The sociological pressure on the best graduate students to do this stuff is intense, and theoretical physicists who don't are shuffled out the door. The price paid (beyond just the money) is that smart people have been lured into a scientific dead-end and away from the most exciting and rapidly-progressing subjects, like biophysics and astrophysics, as well as from difficult but accessible problems in complex and nonlinear systems, all of which need more smarts. But they do know how to market themselves, to the disadvantage of more productive and successful areas of science.