Examining a living fossil

T'is the season to be depressed?/coping with the holiday blues.

Manifest destiny 21st Century?:Pros and cons.

On Darwinism's attempts to put words in our mouths.

Leading Evolutionary Scientists Admit We Have No Evolutionary Explanation of Human Language

Casey Luskin December 19, 2014 3:06 AM

 

 

 

Denyse O'Leary has written here about the difficulty that evolutionary psychology faces in explaining the origin of language. Indeed, back in May, a group of huge names in evolutionary biology, evolutionary anthropology, and evolutionary psychology published a peer-reviewed paper in the journal Frontiers in Psychology admitting that in fact we have no explanation for the origin of language. The abstract strikingly states:

Understanding the evolution of language requires evidence regarding origins and processes that led to change. In the last 40 years, there has been an explosion of research on this problem as well as a sense that considerable progress has been made. We argue instead that the richness of ideas is accompanied by a poverty of evidence, with essentially no explanation of how and why our linguistic computations and representations evolved. We show that, to date, (1) studies of nonhuman animals provide virtually no relevant parallels to human linguistic communication, and none to the underlying biological capacity; (2) the fossil and archaeological evidence does not inform our understanding of the computations and representations of our earliest ancestors, leaving details of origins and selective pressure unresolved; (3) our understanding of the genetics of language is so impoverished that there is little hope of connecting genes to linguistic processes anytime soon; (4) all modeling attempts have made unfounded assumptions, and have provided no empirical tests, thus leaving any insights into language's origins unverifiable. Based on the current state of evidence, we submit that the most fundamental questions about the origins and evolution of our linguistic capacity remain as mysterious as ever, with considerable uncertainty about the discovery of either relevant or conclusive evidence that can adjudicate among the many open hypotheses.
(Marc Hauser, Charles Yang, Robert Berwick, Ian Tattersall, Michael J. Ryan, Jeffrey Watumull, Noam Chomsky and Richard C. Lewontin, "The mystery of language evolution," Frontiers in Psychology, Vol 5:401 (May 7, 2014) (emphases added).)

It's difficult to imagine much stronger words from a more prestigious collection of experts. But what about all of those news stories about apes who learn how to communicate using sign language? Do they show that apes possess or can learn some primitive precursor to humanlike language? No, they say:

Talking birds and signing apes rank among the most fantastic claims in the literature on language evolution, but examination of the evidence shows fundamental differences between child language acquisition and nonhuman species' use of language and language-like systems. For instance, dogs can respond to a few hundred words, but only after thousands of hours of training; children acquire words rapidly and spontaneously generalize their usage in a wide range of contexts. Similarly, Nim Chimpsky, the chimpanzee that produced the only public corpus of data in all animal language studies, produced signs considerably below the expected degree of combinatorial diversity seen in two-year old children, and with no understanding of syntactic structure or semantic interpretation. Though these studies are of potential interest to understanding the acquisition of specialized, artificial skills -- akin to our learning a computer language -- they do not inform understanding of language evolution.

They conclude: "For now, the evidence from comparative animal behavior provides little insight into how our language phenotype evolved. The gap between us and them is simply too great to provide any understanding of evolutionary precursors or the evolutionary processes (e.g., selection) that led to change over time."

 

But what about FOXP2 -- a gene that seems to be connected to language, where humans have a couple of unique amino acid differences compared to nonhuman primates? In The Language of God, Francis Collins presented FOXP2 as something of a miracle mutation that could have caused human language to develop (see pp. 139-141). Time Magazine once claimed that our two amino acid differences in this gene could have caused "the emergence of all aspects of human speech, from a baby's first words to a Robin Williams monologue." These authors would disagree, because, as they point out, we aren't even sure exactly how FOXP2 affects language:

FOXP2 is a transcription factor that up- or down-regulates DNA in many different tissue types (brain, lung, gut lining) at different times during development as well as throughout life. This broad functional effect makes evolutionary analysis difficult. In particular, the exact mechanisms by which FOXP2 mutations disrupt speech remain uncertain, variously posited as disruptions in motor articulation/serialization in speech, vocal learning generally, or broader difficulties with procedural serialization. This is critical because FOXP2 mutations may disrupt only the input/output systems of language, sparing the more internal computations of human language syntax or semantics; or it may be that FOXP2 affects general cognitive processing, such as general serial ordering of procedures. Second, it is not clear whether the amino acid changes distinguishing FOXP2 in humans and nonhumans represent adaptations "for" language, since their functional effects remain unclear. One of the two protein-coding changes along the lineage to modern humans is also associated with the order Carnivora. Since FOXP2 also targets the gut lining, this evolutionary step may have had little to do directly with language but instead with digestion modifications driven by forest-to-savannah habit and so dietary change...

According to the paper, claims that mutations in FOXP2 explain the origin of language cannot be true because, as the authors put it, "we lack a connect-the-dots account of any gene to language phenotype."

 

Of course the authors propose various avenues of research that they think might someday lead to an understanding how language arose. But for the present, their analysis is discouraging: "Until such evidence is brought forward, understanding of language evolution will remain one of the great mysteries of our species."

But you already knew that.

Your Computer Doesn't Like You

Michael Egnor December 15, 2014 2:30 AM

 

Actually, your computer doesn't dislike you, either. Your computer has no opinion about you at all, because it has no opinions whatsoever.

This is news to Stephen Hawking and Elon Musk, who -- as Erik J. Larson has commented here -- recently have warned humanity that computers are on the verge of acquiring minds and could take over the world and end mankind.

Computers, of course, cannot "take over the world and end mankind," because computers have no intelligent agency at all. Intelligence, as denoted in "artificial intelligence," corresponds roughly to what Aristotle meant by intellect and will. Intellect and will are the rational capabilities of human beings -- the ability to reason, to contemplate universals such as good and evil and right and wrong, to love and hate, to judge and intend and carry out decisions arrived at through reason. These are capabilities of human beings, and only of human beings.

Inanimate devices have agency too, but they have unintelligent agency. Computers can store electrons, move electrons about, light up a screen, boot up, crash, freeze, and so on. Computers can of course be a tool by which human beings express their own human intelligent agency. When a person commits bank fraud via a computer, the person, not the computer, goes to jail. Computers have no intelligent agency of their own, and never will, any more than the paperweight on your desk has intelligent agency.

The only way a computer can hurt you, on its own, is if it falls on your foot.

Computers are electromechanical devices that we use as tools. They differ only in complexity from other tools like books, which we use to store and retrieve representations of knowledge. We make tools, and we use tools, and they serve our ends. We put representations of our intentions and knowledge and desires and memories and conceptual insights and errors into computers, and the software that we have written maps our inputs to outputs, and then we analyze and ponder the outputs. Nowhere in this process is there the slightest bit of thinking on the part of the computer. Computers can't think because things like tools -- even tools made in Silicon Valley -- can't think. Computers are devices we use for our own purposes, and like all devices, sometimes the consequences aren't what we expected. Sometimes the book really changes the way we think about things, and sometimes we drop the book on our foot. But the consequences of using tools -- and the consequences can on occasion be transformative for humanity -- are consequences entirely of human purposes and mistakes.  

We've been through this before. After the invention of writing in Sumer, parchment didn't acquire a mind and inflict evil on humanity. But writing did change civilization. After the invention of the printing press, books didn't acquire a mind and inflict evil upon humanity. But the printing press did change civilization. Nor will computers in the 21st century acquire a mind and inflict evil on humanity, because computers can't think any more than parchment or books can think.

But the information age will change civilization.

The salient harm that the silly "artificial intelligence" trope will do to humanity, aside from the general stupidity the concept fosters, is that it will distract us from the astonishingly potent transformation of our civilization that we will bring about in the information revolution. The transformation will be much more radical and rapid than the transformation in the 15th century caused by the printing press. Within a century or two after Gutenberg, millions of people had read things they had never read before, and thought of things they had never thought of before, and doubted and believed new things and found new ways to change their lives and their cultures. The Renaissance flowered, the Reformation raged, the Enlightenment (however misnamed) bloomed, and modernity dawned.

By 1648 northern and central Europe was bled white and a third of the population of Germany was dead from famine and war. By 1789 Napoleon was studying his schoolbooks.  By 1867 Marx had a publisher for Das Kapital, and by 1925 Hitler published volume one of Mein Kampf.

Parchment and books and computers are the tools -- merely the tools -- by which humanity transforms itself.

The information revolution will leverage human intentions and mistakes in ways we can only begin to imagine. None of the transformation will have anything to do with science fiction stories about malevolent robots. It's the malevolent humans -- and even the well-intentioned humans -- who will fashion our ends

Artificial intelligence is an oxymoron. Only human beings have intelligence. We use tools to bring about our ends, and the human information revolution made possible by our tools will transform our civilization, for better or worse and probably both. But the only real threat "artificial intelligence" poses is that it disposes us to dread HAL when we should be contemplating the transformation -- a transformation far more fundamental and astonishing than writing or the printing press -- that humanity will bring upon itself via the information revolution.

René Girard has a few thoughts about what we do to ourselves.

 

The divine law and bloodVIII:swimming against the flow.

From the spring 2013 edition of "stanford Medicine"

 

AGAINST THE FLOW
WHAT’S BEHIND THE DECLINE IN BLOOD TRANSFUSIONS?

by Sarah C.P. Williams
Illustration by Jonathon Rosen

One day in 2011, an ambulance pulled up to the Stanford emergency room and paramedics unloaded a man in his 30s who had crashed his motorcycle. He was in critical condition: Tests showed dangerously low blood pressure, indicating that around 40 percent of his blood was lost. And an ultrasound revealed that the blood was collecting in his belly, suggesting that one or more of his abdominal organs was the source of the blood loss.

Paul Maggio, MD, a trauma surgeon and co-director of critical care medicine at Stanford Hospital & Clinics, sped the patient into the operating room. But he made sure that the technicians prepping his operating room took the time to set up one key piece of equipment, called an intraoperative cell salvage device, which is now commonly used in trauma cases. As the patient lay on the operating table and Maggio made the first cuts into his abdomen, suction devices slurped up the loose blood, directing it away from the surgery site through tubes. But instead of leading to a container bound for disposal, the tubes led to the salvage device.

The ATM-sized machine spun the blood to separate its components, cleaned it of any debris that had been suctioned up from the abdomen and sent it back out into fresh bags. From there, the blood was shunted right back to the patient’s body, through intravenous tubes poking into his veins. The cell salvage device has been around for decades, but only recently has evidence emerged that autotransfusion — giving patients their own blood instead of blood from donors — leads to better surgery outcomes. As a result, the use of the machines has gone from extremely rare to commonplace. Today, hospitals that have the machines use them in many scheduled abdominal and heart surgeries and routinely in trauma cases involving massive bleeding.

“Autotransfusing this patient spared him from getting more banked donor blood and from all the risks associated with it,” says Maggio of the motorcycle crash victim. He turned out to have an injury to his spleen, which Maggio repaired. In all, around 2 liters of blood were collected from the patient’s abdomen, processed through the salvage device, and transfused back into his body.

Blood transfusions involve routing a needle into one of a patient’s veins — most often in an arm — and attaching a thin tube to the needle. Blood flows through the tube directly into the patient’s blood vessels. Ten years ago, a patient like Maggio’s would most likely have had a transfusion of blood donated by volunteers at the Stanford Blood Center. But over the past decade, a growing body of research has revealed that in hospitals around the world, donated blood is used more often, and in larger quantities, than is needed to help patients — both in operating rooms and hospital wards.

Some of the research has been conducted by physicians working with patients who refuse donated blood on religious grounds; other findings have come from the front lines of the war in Afghanistan, where blood is hard to transport; and some studies have been inspired simply by the rising cost of blood and a desire to save resources. Some findings are new, and others, like studies by Stanford’s Tim Goodnough, MD, a hematologist and the director of transfusion services, are years old but only recently being noticed. The takeaway message from all is the same: While blood is precious and continues to save lives, its use can be minimized and fine-tuned to optimize patients’ health and reduce costs.

The American Medical Association brought attention to the subject last fall at its national summit on the overuse of five medical treatments. Blood transfusions were on the list (along with heart stents, ear tubes, antibiotics and inducing birth in pregnant women).

“From the clinical standpoint, I’m not really thinking about resources or cost,” says Maggio, who’s also an assistant professor of surgery. “I’m thinking about giving the patient the best care.” Donated blood carries risks, albeit very slight, of infection and setting off an immune reaction. But research is also showing that even when these drastic outcomes are avoided, there’s something else about donated blood — which scientists don’t fully understand — that could slow recovery time or increase complications.

While autotransfusion for trauma patients is growing, and guidelines for blood transfusions are changing in response to this new research, altering the protocols that doctors have been using for so many years is a slow process.

 

Changing the routine

At Stanford, it took an innovative new program that used alerts on doctors’ computer systems to enforce fewer blood transfusions

But the push paid off: Blood use in the operating rooms, emergency rooms and hospital wards of both Stanford and the Lucile Packard Children’s Hospital has declined by 10 percent in just a few years. At Packard Children’s alone, 460 transfusions and $165,000 were saved in one year, according to a pilot study conducted Feb. 1, 2009, through Jan. 31, 2010.

‘There’s this idea ingrained in the culture of medicine that people will die if they don’t have a certain level of blood, that blood is the ultimate lifesaver.’
– Patricia Ford, MD, Founder and Director of Pennsylvannia Hospital’s Center for Bloodless Medicine and Surgery at Penn Medicine

“I think we’re probably still giving too much blood in some of these situations,” says Maggio. “But we hope that physicians are becoming better informed about when to give blood.”
People most often need blood transfusions when they’re in one of three situations: They lose blood from a major surgery that’s been scheduled for weeks or months; they lose blood in a way that their body won’t be able to replace, such as a blood cancer that shuts down the body’s ability to make blood cells; or they lose blood during a more sudden trauma — either an external wound or internal bleeding.
“For that first group of patients, scheduled for elective surgery, if you can plan ahead, you should be able to avoid using blood,” says Goodnough, a professor of pathology and of medicine. In those patients, drugs can boost a patient’s own blood production ahead of surgery, blood can be collected from a patient ahead of time to re-infuse later, precautions can be taken to prevent sudden blood loss, or autotransfusion machines like the cell salvage device can be set up. “Where we still need a national blood inventory is for patients who can’t plan ahead,” says Goodnough.
In the cases where physicians continue to give blood when it might not be needed, it’s often because they can’t imagine not doing everything they can to help a patient — and blood has always been viewed as having far more benefits than risks in almost any population of patients. But now, that risk-benefit analysis is changing.
“There’s this idea ingrained in the culture of medicine that people will die if they don’t have a certain level of blood, that blood is the ultimate lifesaver,” says Patricia Ford, MD, founder and director of Pennsylvania Hospital’s Center for Bloodless Medicine and Surgery at Penn Medicine. “And that’s true in some specific situations, but for most patients in most situations it’s just not true.” Ford’s center is one of the oldest and largest in the country that specializes in treating patients without donated blood; dozens of others have been created over the past decades but mostly at a smaller scale.

Going bloodless

 

Every year, Ford treats or operates on around 700 Jehovah’s Witnesses, whose religion prohibits transfusions of blood that is not one’s own. Since 1996, she has been fine-tuning ways to give these patients the best care as well as ways to apply these techniques to the broader population.

“Many physicians I talked to at the beginning had this misperception that a lot of patients just can’t survive without receiving blood,” says Ford. “I may have even thought that myself to some degree. But what I rapidly learned was you can care for these patients by just applying some easy strategies.”

In fact, a study published in August 2012 by researchers at the Cleveland Clinic concluded that Jehovah’s Witness patients recovered better from heart surgery than patients who received blood transfusions. It’s the longest study conducted on such patients — the researchers followed them for up to 20 years. The Jehovah’s Witness patients had higher five-year survival rates, fewer heart attacks following the surgery and fewer complications including sepsis and renal failure. The better outcomes might not have been due to the absence of transfusions but to differences in care received — the patients were more likely to be treated for low blood levels before surgery by receiving iron supplements and vitamins, and every patient’s surgery included use of an intraoperative cell salvage device. The findings suggest that these methods employed for bloodless surgeries could help patients beyond the Jehovah’s Witness community.

At Pennsylvania Hospital, Ford has discovered that, for scheduled surgeries, one of the best ways to avoid the need for blood transfusions is to test patients’ levels of hemoglobin — the protein in red blood cells that carries oxygen — well before their surgery. If the levels are low, then the patient can take vitamin K and iron supplements, which help the body produce more blood cells and help red blood cells more efficiently carry oxygen throughout the body. The practice of testing for low red blood cell levels, or anemia, is now beginning to spread from specialized clinics like Ford’s to other hospitals around the country.

“Testing for anemia was just not on people’s radar screens, because they knew that they could always give the patient blood,” says Ford. Now, many doctors consider testing a patient’s blood cell levels just as important as testing their heart and lung health before surgery. This shift is supported by studies such as an October 2012 analysis in the Annals of Thoracic Surgery of the outcomes of more than 17,000 heart surgeries, which found an increase in stroke, death during surgery and death after surgery when patients were anemic before surgery.

At Stanford, standard pre-surgery tests include blood counts for patients who are expected to lose large amounts of blood, says Goodnough. If anemia is suggested by the results, clinicians aim to manage the condition before surgery.

At Penn, Ford also emphasizes the conservation of blood during surgery, often by using an intraoperative cell salvage device. Patients can also donate blood in the weeks leading up to a scheduled surgery and their own saved blood — called an autologous donation — can be used for a transfusion if necessary. In the 1980s, Goodnough studied the usefulness of autologous donations in different patient population groups and pushed for its broader usage. It’s now considered a mainstream way of reducing the need for donated blood. “It sounds like a mundane concept now, but it was quite progressive when we first started looking at it,” says Goodnough.

Among Ford’s lessons with the Jehovah’s Witnesses, she says that perhaps her most important has been that there’s no magic hemoglobin number that tells doctors when a patient will start exhibiting signs of anemia. Typically, doctors consider hemoglobin above 12 to be normal, and hemoglobin below 7 or 8 to indicate the need for a blood transfusion. But Ford and a growing number of other doctors think those numbers could be pushed down further, a change that would require new studies for many to adapt.

“It’s not unusual for me to see a patient who has a hemoglobin of 5 and they look as healthy as anyone walking down the street,” says Ford. Of course, there also can be patients who become sick with much higher hemoglobin levels, but Ford would like to see more doctors treating blood levels based on symptoms, not a number. Goodnough agrees: “It’s really hard to demonstrate at what level of hemoglobin a transfusion will help a patient,” he says. “And we’re increasingly seeing that for most patients, hemoglobin has to be exceptionally low to have effects.” But it depends more on the patient’s health and risk factors, he says. There’s no one-size-fits-all solution.

Ezekiel28 The septuagint

1 And the word of the Lord came to me, saying, 2 And thou, son of man, say to the prince of Tyrus, Thus saith the Lord; Because thine heart has been exalted, and thou hast said, I am God, I have inhabited the dwelling of God in the heart of the sea; yet thou art man and not God, though thou hast set thine heart as the heart of God: 3 art thou wiser than Daniel? or have not the wise instructed thee with their knowledge? 4 Hast thou gained power for thyself by thine [own] knowledge or thine [own] prudence, and [gotten] gold and silver in thy treasures? 5 By thy abundant knowledge and thy traffic thou hast multiplied thy power; thy hart has been lifted up by thy power. 6 Therefore thus saith the Lord; Since thou hast set thine heart as the hart of God; 7 because of this, behold, I [will] bring on thee strange plagues from the nations; and they shall draw their swords against thee, and against the beauty of thy knowledge, 8 and they shall bring down thy beauty to destruction. And they shall bring thee down; and thou shalt die the death of the slain in the heart of the sea. 9 Wilt thou indeed say, I am God, before them that slay thee? whereas thou art man, and not God. 10 Thou shalt perish by the hands of strangers among the multitude of the uncircumcised: for I have spoken it, saith he Lord. 11 And the word of the Lord came to me, saying, 12 Son of man, take up a lamentation for the prince of Tyre, and say to him, Thus saith the Lord God; Thou art a seal of resemblance, and crown of beauty. 13 Thou wast in the delight of the paradise of God; thou hast bound upon thee every precious stone, the sardius, and topaz, and emerald, and carbuncle, and sapphire, and jasper, and silver, and gold, and ligure, and agate, and amethyst, and chrysolite, and beryl, and onyx: and thou hast filled thy treasures and thy stores in thee with gold. 14 From the day that thou wast created thou [wast] with the cherub: I set thee on the holy mount of God; thou wast in the midst of the stones of fire. 15 Thou wast faultless in thy days, from the day that thou wast created, until iniquity was found in thee. 16 Of the abundance of thy merchandise thou hast filled thy storehouses with iniquity, and hast sinned: therefore thou hast been cast down wounded from the mount of God, and the cherub has brought thee out of the midst of the stones of fire. 17 Thy heart has been lifted up because of thy beauty; thy knowledge has been corrupted with thy beauty: because of the multitude of thy sins I have cast thee to the ground, I have caused thee to be put to open shame before kings. 18 Because of the multitude of thy sins and the iniquities of thy merchandise, I have profaned thy sacred things; and I will bring fire out of the midst of thee, this shall devour thee; and I will make thee [to be] ashes upon thy land before all that see thee. 19 And all that know thee among the nations shall groan over thee: thou art gone to destruction, and thou shalt not exist any more. 20 And the word of the Lord came to me, saying, 21 Son of man, set thy face against Sidon, and prophesy against it, 22 and say, Thus saith the Lord; Behold, I am against thee, O Sidon; and I will be glorified in thee; and thou shalt know that I am the Lord, when I have wrought judgments in thee, and I will be sanctified in thee. 23 Blood and death [shall be] in thy streets; and [men] wounded with swords shall fall in thee and on every side of thee; and they shall know that I am the Lord. 24 And there shall no more be in the house of Israel a thorn of bitterness and a pricking briar proceeding from them that are round about them, who dishonoured them; and they shall know that I am the Lord. 25 Thus saith the Lord God; I will also gather Israel from the nations, among whom they have been scattered, and I will be sanctified among them, and before the peoples and nations: and they shall dwell upon their land, which I gave to my servant Jacob. 26 Yea, they shall dwell upon it safely, and they shall build houses, and plant vineyards, and dwell securely, when I shall execute judgment on all that have dishonoured them, [even] on those [that are] round about them; and they shall know that I am the Lord their God, and the God of their fathers.

ΚΑΙ ἐγένετο λόγος Κυρίου πρός με λέγων· 2 καὶ σὺ υἱὲ ἀνθρώπου, εἰπὸν τῷ ἄρχοντι Τύρου· τάδε λέγει Κύριος· ἀνθ' ὧν ὑψώθη σου ἡ καρδία, καὶ εἶπας· θεός εἰμι ἐγώ, κατοικίαν θεοῦ κατῴκησα ἐν καρδίᾳ θαλάσσης, σὺ δὲ εἶ ἄνθρωπος καὶ οὐ Θεός, καὶ ἔδωκας τὴν καρδίαν σου ὡς καρδίαν Θεοῦ. 3 μὴ σοφώτερος εἶ σὺ τοῦ Δανιήλ; ἢ σοφοὶ οὐκ ἐπαίδευσάν σε τῇ ἐπιστήμη αὐτῶν; 4 μὴ ἐν τῇ ἐπιστήμῃ σου ἢ τῇ φρονήσει σου ἐποίησας σεαυτῷ δύναμιν καὶ χρυσίον καὶ ἀργύριον ἐν τοῖς θησαυροῖς σου; 5 ἐν τῇ πολλῇ ἐπιστήμῃ σου καὶ ἐμπορίᾳ σου ἐπλήθυνας δύναμίν σου, ὑψώθη ἡ καρδία σου ἐν τῇ δυνάμει σου. 6 διὰ τοῦτο τάδε λέγει Κύριος· ἐπειδὴ δέδωκας τὴν καρδίαν σου ὡς καρδίαν Θεοῦ, 7 ἀντὶ τούτου ἰδοὺ ἐγὼ ἐπάγω ἐπὶ σὲ ἀλλοτρίους λοιμοὺς ἀπὸ ἐθνῶν, καὶ ἐκκενώσουσι τὰς μαχαίρας αὐτῶν ἐπὶ σὲ καὶ ἐπὶ τὸ κάλλος τῆς ἐπιστήμης σου καὶ στρώσουσι τὸ κάλλος σου εἰς ἀπώλειαν· 8 καὶ καταβιβάσουσί σε, καὶ ἀποθανῇ θανάτῳ τραυματιῶν ἐν καρδίᾳ θαλάσσης. 9 μὴ λέγων ἐρεῖς· Θεός εἰμι ἐγώ, ἐνώπιον τῶν ἀναιρούντων σε; σὺ δὲ εἶ ἄνθρωπος καὶ οὐ Θεός. 10 ἐν πλήθει ἀπεριτμήτων ἀπολῇ ἐν χερσὶν ἀλλοτρίων, ὅτι ἐγὼ ἐλάλησα, λέγει Κύριος. - 11 Καὶ ἐγένετο λόγος Κυρίου πρός με λέγων· 12 υἱὲ ἀνθρώπου, λαβὲ θρῆνον ἐπὶ τὸν ἄρχοντα Τύρου καὶ εἰπὸν αὐτῷ· τάδε λέγει Κύριος Κύριος· σὺ ἀποσφράγισμα ὁμοιώσεως καὶ στέφανος κάλλους 13 ἐν τῇ τρυφῇ τοῦ παραδείσου τοῦ Θεοῦ ἐγενήθης· πάντα λίθον χρηστὸν ἐνδέδεσαι, σάρδιον καὶ τοπάζιον καὶ σμάραγδον καὶ ἄνθρακα καὶ σάπφειρον καὶ ἴασπιν καὶ ἀργύριον καὶ χρυσίον καὶ λιγύριον καί ἀχάτην καὶ ἀμέθυστον καὶ χρυσόλιθον καὶ βηρύλλιον καὶ ὀνύχιον, καὶ χρυσίου ἐνέπλησας τοὺς θησαυρούς σου καὶ τὰς ἀποθήκας σου ἐν σοὶ 14 ἀφ' ἧς ἡμέρας ἐκτίσθης σύ. μετὰ τοῦ Χεροὺβ ἔθηκά σε ἐν ὄρει ἁγίῳ Θεοῦ, ἐγενήθης ἐν μέσῳ λίθων πυρίνων. 15 ἐγενήθης σὺ ἄμωμος ἐν ταῖς ἡμέραις σου, ἀφ' ἧς ἡμέρας σὺ ἐκτίσθης ἕως εὑρέθη τὰ ἀδικήματα ἐν σοί. 16 ἀπὸ πλήθους τῆς ἐμπορίας σου ἔπλησας τὰ ταμιεῖά σου ἀνομίας καὶ ἥμαρτες καὶ ἐτραυματίσθης ἀπὸ ὄρους τοῦ Θεοῦ, καὶ ἤγαγέ σε τὸ Χεροὺβ ἐκ μέσου λίθων πυρίνων. 17 ὑψώθη ἡ καρδία σου ἐπὶ τῷ κάλλει σου, διεφθάρη ἡ ἐπιστήμη σου μετὰ τοῦ κάλλους σου· διὰ πλῆθος ἁμαρτιῶν σου ἐπὶ τὴν γῆν ἔρριψά σε, ἐναντίον βασιλέων ἔδωκά σε παραδειγματισθῆναι. 18 διὰ τὸ πλῆθος τῶν ἁμαρτιῶν σου καὶ τῶν ἀδικιῶν τῆς ἐμπορίας σου ἐβεβήλωσα τά ἱερά σου, καὶ ἐξάξω πῦρ ἐκ μέσου σου, τοῦτο καταφάγεταί σε· καὶ δώσω σε εἰς σποδὸν ἐπὶ τῆς γῆς σου ἐναντίον πάντων τῶν ὁρώντων σε. 19 καὶ πάντες οἱ ἐπιστάμενοί σε ἐν τοῖς ἔθνεσι στυγνάσουσιν ἐπὶ σέ· ἀπώλεια ἐγένου καὶ οὐχ ὑπάρξεις ἔτι εἰς τὸν αἰῶνα. 20 Καὶ ἐγένετο λόγος Κυρίου πρός με λέγων· 21 υἱὲ ἀνθρώπου, στήρισον τὸ πρόσωπόν σου ἐπὶ Σιδῶνα καὶ προφήτευσον ἐπ' αὐτὴν 22 καὶ εἰπόν· τάδε λέγει Κύριος· ἰδοὺ ἐγὼ ἐπὶ σέ, Σιδών, καὶ ἐνδοξασθήσομαι ἐν σοί, καὶ γνώσῃ ὅτι ἐγώ εἰμι Κύριος ἐν τῷ ποιῆσαί με ἐν σοὶ κρίματα, καὶ ἁγιασθήσομαι ἐν σοί. 23 αἷμα καὶ θάνατος ἐν ταῖς πλατείαις σου, καὶ πεσοῦνται τετραυματισμένοι ἐν μαχαίραις ἐν σοὶ περικύκλῳ σου· καὶ γνώσονται διότι ἐγώ εἰμι Κύριος. - 24 Καὶ οὐκ ἔσονται οὐκέτι ἐν τῷ οἴκῳ τοῦ ᾿Ισραὴλ σκόλοψ πικρίας καὶ ἄκανθα ὀδύνης ἀπὸ πάντων τῶν περικύκλῳ αὐτῶν τῶν ἀτιμασάντων αὐτούς· καὶ γνώσονται ὅτι ἐγώ εἰμι Κύριος. 25 τάδε λέγει Κύριος Κύριος· καὶ συνάξω τὸν ᾿Ισραὴλ ἐκ τῶν ἐθνῶν, οὗ διεσκορπίσθησαν ἐκεῖ, καὶ ἁγιασθήσομαι ἐν αὐτοῖς ἐνώπιον τῶν λαῶν καὶ τῶν ἐθνῶν· 26 καὶ κατοικήσουσιν ἐπὶ τῆς γῆς αὐτῶν, ἣν δέδωκα τῷ δούλῳ μου ᾿Ιακώβ, καὶ κατοικήσουσιν ἐπ' αὐτῆς ἐν ἐλπίδι καὶ οἰκοδομήσουσιν οἰκίας καὶ φυτεύσουσιν ἀμπελῶνας καὶ κατοικήσουσιν ἐν ἐλπίδι, ὅταν ποιήσω κρίμα ἐν πᾶσι τοῖς ἀτιμάσασιν αὐτοὺς ἐν τοῖς κύκλῳ αὐτῶν· καὶ γνώσονται ὅτι ἐγώ εἰμι Κύριος ὁ Θεὸς αὐτῶν καὶ ὁ Θεὸς τῶν πατέρων αὐτῶν. 

Ezekiel28 The Tanakh

1.Then the word of the Lord came to me, saying: א. וַיְהִי דְבַר יְהֹוָה אֵלַי לֵאמֹר:

2. "Son of man, say to the prince of Tyre: So said the Lord God: Because your heart is proud, and you said, 'I am a god, I have sat in a seat of God, in the heart of the seas,' but you are a man and not a god, yet you have made your heart like the heart of God. ב. בֶּן אָדָם אֱמֹר לִנְגִיד צֹר כֹּה אָמַר | אֲדֹנָי יֱהֹוִה יַעַן גָּבַהּ לִבְּךָ וַתֹּאמֶר אֵל אָנִי מוֹשַׁב אֱלֹהִים יָשַׁבְתִּי בְּלֵב יַמִּים וְאַתָּה אָדָם וְלֹא אֵל וַתִּתֵּן לִבְּךָ כְּלֵב אֱלֹהִים:

3. Behold, are you wiser than Daniel, that no secret is hidden from you? ג. הִנֵּה חָכָם אַתָּה מִדָּנִאֵל כָּל סָתוּם לֹא עֲמָמוּךָ:

4. With your wisdom and with your understanding did you acquire wealth for yourself, and gather gold and silver in your treasurehouses? ד. בְּחָכְמָתְךָ וּבִתְבוּנָתְךָ עָשִׂיתָ לְּךָ חָיִל וַתַּעַשׂ זָהָב וָכֶסֶף בְּאוֹצְרוֹתֶיךָ:

5. With your great wisdom in your commerce did you increase your wealth, that your heart became haughty with your wealth? ה. בְּרֹב חָכְמָתְךָ בִּרְכֻלָּתְךָ הִרְבִּיתָ חֵילֶךָ וַיִּגְבַּהּ לְבָבְךָ בְּחֵילֶךָ:

6. Therefore, so said the Lord God: Because you made your heart like the heart of God, ו. לָכֵן כֹּה אָמַר אֲדֹנָי יֱהֹוִה יַעַן תִּתְּךָ אֶת לְבָבְךָ כְּלֵב אֱלֹהִים:

7. Therefore, behold I am bringing foreigners, the strong of the nations, upon you, and they will draw their swords on the beauty of your wisdom and profane your brightness. ז. לָכֵן הִנְנִי מֵבִיא עָלֶיךָ זָרִים עָרִיצֵי גּוֹיִם וְהֵרִיקוּ חַרְבוֹתָם עַל יְפִי חָכְמָתֶךָ וְחִלְּלוּ יִפְעָתֶךָ:

8. Into the Pit they will lower you, and you will die the deaths of those who are slain, in the heart of the seas. ח. לַשַּׁחַת יוֹרִדוּךָ וָמַתָּה מְמוֹתֵי חָלָל בְּלֵב יַמִּים:

9. Will you say, "I am a god" before your slayer? Indeed, you are a man and not a god in the hand of your slayer. ט. הֶאָמֹר תֹּאמַר אֱלֹהִים אָנִי לִפְנֵי הֹרְגֶךָ וְאַתָּה אָדָם וְלֹא אֵל בְּיַד מְחַלְלֶךָ:

10. The deaths of the uncircumcised you shall die at the hand of foreigners, for I have spoken," says the Lord God. י. מוֹתֵי עֲרֵלִים תָּמוּת בְּיַד זָרִים כִּי אֲנִי דִבַּרְתִּי נְאֻם אֲדֹנָי יֱהֹוִה:

11. Then the word of the Lord came to me, saying: יא. וַיְהִי דְבַר יְהֹוָה אֵלַי לֵאמֹר:

12. "Son of man, raise a lamentation over the king of Tyre and say to him, So said the Lord God: You are the one who engraves images, full of wisdom and perfect in beauty. יב. בֶּן אָדָם שָׂא קִינָה עַל מֶלֶךְ צוֹר וְאָמַרְתָּ לּוֹ כֹּה אָמַר אֲדֹנָי יֱהֹוִה אַתָּה חוֹתֵם תָּכְנִית מָלֵא חָכְמָה וּכְלִיל יֹפִי:

13. In Eden, the garden of God you were; every precious stone was [set in] your covering; ruby, topaz, diamond, chrysolite, onyx, and jasper, sapphire, carbuncle, and crystal and gold; the work of your drums and your orifices is in you; on the day of your creation they were established. יג. בְּעֵדֶן גַּן אֱלֹהִים הָיִיתָ כָּל אֶבֶן יְקָרָה מְסֻכָתֶךָ אֹדֶם פִּטְדָה וְיַהֲלֹם תַּרְשִׁישׁ שֹׁהַם וְיָשְׁפֵה סַפִּיר נֹפֶךְ וּבָרְקַת וְזָהָב מְלֶאכֶת תֻּפֶּיךָ וּנְקָבֶיךָ בָּךְ בְּיוֹם הִבָּרַאֲךָ כּוֹנָנוּ:

14. You were a cherub of great measure, that covers, and I gave that to you; you were on the mount of the sanctuary of God: you walked among stones of fire. יד. אַתְּ כְּרוּב מִמְשַׁח הַסּוֹכֵךְ וּנְתַתִּיךָ בְּהַר קֹדֶשׁ אֱלֹהִים הָיִיתָ בְּתוֹךְ אַבְנֵי אֵשׁ הִתְהַלָּכְתָּ:

15. You were perfect in your ways from the day you were created until wrongdoing was found in you. טו. תָּמִים אַתָּה בִּדְרָכֶיךָ מִיּוֹם הִבָּרְאָךְ עַד נִמְצָא עַוְלָתָה בָּךְ:

16. Because of the multitude of your commerce, they filled you with violence and you sinned, and I shall cast you as profane from the mountain of God, and I shall destroy you, O covering cherub, from among the stones of fire. טז. בְּרֹב רְכֻלָּתְךָ מָלוּ תוֹכְךָ חָמָס וַתֶּחֱטָא וָאֲחַלֶּלְךָ מֵהַר אֱלֹהִים וָאַבֶּדְךָ כְּרוּב הַסּוֹכֵךְ מִתּוֹךְ אַבְנֵי אֵשׁ:

17. Your heart became haughty because of your beauty; you destroyed your wisdom with your brightness; I have cast you upon the ground; I have set you before kings to gaze upon you. יז. גָּבַהּ לִבְּךָ בְּיָפְיֶךָ שִׁחַתָּ חָכְמָתְךָ עַל יִפְעָתֶךָ עַל אֶרֶץ הִשְׁלַכְתִּיךָ לִפְנֵי מְלָכִים נְתַתִּיךָ לְרַאֲוָה בָךְ:

18. Because of the multitude of your iniquities, with the wrongdoing of your commerce, you profaned your sanctity, and I shall bring forth fire out of your midst-it will consume you, and I shall make you ashes on the ground before the eyes of all who see you. יח. מֵרֹב עֲו‍ֹנֶיךָ בְּעָוֶל רְכֻלָּתְךָ חִלַּלְתָּ מִקְדָּשֶׁיךָ וָאוֹצִא אֵשׁ מִתּוֹכְךָ הִיא אֲכָלַתְךָ וָאֶתֶּנְךָ לְאֵפֶר עַל הָאָרֶץ לְעֵינֵי כָּל רֹאֶיךָ:

19. All who know you among the peoples will wonder over you; you shall be a terror, and you shall be no more, ever." יט. כָּל יוֹדְעֶיךָ בָּעַמִּים שָׁמְמוּ עָלֶיךָ בַּלָּהוֹת הָיִיתָ וְאֵינְךָ עַד עוֹלָם:

20. Then the word of the Lord came to me, saying: כ. וַיְהִי דְבַר יְהֹוָה אֵלַי לֵאמֹר:

21. "Son of man! Set your face toward Zidon and prophesy about her. כא. בֶּן אָדָם שִׂים פָּנֶיךָ אֶל צִידוֹן וְהִנָּבֵא עָלֶיהָ:

22. And you shall say; So said the Lord God: Behold I am against you, Zidon, and I shall be honored in your midst, and you will know that I am the Lord when I perform judgments in her and I shall be sanctified in her. כב. וְאָמַרְתָּ כֹּה אָמַר אֲדֹנָי יֱהֹוִה הִנְנִי עָלַיִךְ צִידוֹן וְנִכְבַּדְתִּי בְּתוֹכֵךְ וְיָדְעוּ כִּי אֲנִי יְהֹוָה בַּעֲשׂוֹתִי בָהּ שְׁפָטִים וְנִקְדַּשְׁתִּי בָהּ:

23. And I shall send into her pestilence and blood in her streets, and they will judge themselves as slain in her midst by the sword [coming] upon her from all around, and they will know that I am the Lord. כג. וְשִׁלַּחְתִּי בָהּ דֶּבֶר וָדָם בְּחוּצוֹתֶיהָ וְנִפְלַל חָלָל בְּתוֹכָהּ בְּחֶרֶב עָלֶיהָ מִסָּבִיב וְיָדְעוּ כִּי אֲנִי יְהֹוָה:

24. And there will no longer be to the house of Israel a pricking briar or a painful thorn from all that are around them, who plunder them, and they will know that I am the Lord God. כד. וְלֹא יִהְיֶה עוֹד לְבֵית יִשְׂרָאֵל סִלּוֹן מַמְאִיר וְקוֹץ מַכְאִב מִכֹּל סְבִיבֹתָם הַשָּׁאטִים אוֹתָם וְיָדְעוּ כִּי אֲנִי אֲדֹנָי יֱהֹוִה:

25. So says the Lord God: When I gather in the house of Israel from the peoples among whom they have been scattered, and I have been sanctified through them in the eyes of the nations, then shall they dwell on their land that I gave to My servant, to Jacob. כה. כֹּה אָמַר אֲדֹנָי יֱהֹוִה בְּקַבְּצִי | אֶת בֵּית יִשְׂרָאֵל מִן הָעַמִּים אֲשֶׁר נָפֹצוּ בָם וְנִקְדַּשְׁתִּי בָם לְעֵינֵי הַגּוֹיִם וְיָשְׁבוּ עַל אַדְמָתָם אֲשֶׁר נָתַתִּי לְעַבְדִּי לְיַעֲקֹב:

26. And they shall dwell upon it securely, and they shall build houses and plant vineyards and dwell securely when I execute judgments against all those who plunder them from all around them, and they shall know that I am the Lord their God." כו. וְיָשְׁבוּ עָלֶיהָ לָבֶטַח וּבָנוּ בָתִּים וְנָטְעוּ כְרָמִים וְיָשְׁבוּ לָבֶטַח בַּעֲשׂוֹתִי שְׁפָטִים בְּכֹל הַשָּׁאטִים אֹתָם מִסְּבִיבֹתָם וְיָדְעוּ כִּי אֲנִי יְהֹוָה אֱלֹהֵיהֶם:

Whence the controversy?

Stephen Meyer at the University Club: Why Are We Still Debating Darwin?

Tom Bethell March 21, 2012 11:22 AM

In his "Socrates in the City" talk in Washington last week, Steve Meyer asked: "Is there a scientific controversy about the theory of evolution?" After quoting many spokesmen for official science who deny the existence of any such controversy, or any reason to doubt evolutionary theory whatsoever, Meyer showed that there are significant reasons to doubt both biological and chemical evolutionary theory.

He first addressed the problems associated with chemical evolutionary theory, which "attempts to explain the origin of the first life from simpler pre-existing chemicals." Here he explained the critical question of the origin of genetic information. This is the problem he addressed in his bookSignature in the Cell, a problem that has beset all attempts to explain the origin of life by reference to undirected chemical evolutionary processes.

The most important idea for laymen to grasp is that of biological information. It's difficult to understand "exactly what information is," Meyer has written. It's not a physical thing. He quotes the evolutionary biologist George Williams as saying that information "doesn't have mass or charge or length," and matter "doesn't have bytes." It follows that matter and information belong to "two separate domains."

Information in biology is best understood as analogous to software code. Recall Bill Gates's comment: "DNA is like a computer program but far, far more advanced than any software ever created."

Software is a set of instructions for a new program in a computer. Likewise, DNA contains a set of instructions for the assembly of parts, namely proteins, within a cell. In the 19th century the cell was thought to be simple. Darwin and his contemporaries had no way of knowing just how complex it was. The cell today is sometimes compared to a high-tech factory. (Except it's much more complex than that -- factories can't replicate themselves.)

Here is the key question: How did the requisite information get into the DNA in the first place? Without it, the first cell would never have been constructed and life would never have started. So the question about information is closely related to the question: How did life begin?

Charles Thaxton, a co-author of The Mystery of Life's Origins, told Meyer that the origin-of-life question is still unanswered. When Ben Stein asked Richard Dawkins in Expelled how life began, Dawkins said he had no idea. Stanley Miller performed a famous experiment in 1952 showing that some amino acids can be generated artificially, but that was as far as they could get. They were far short of life itself. (And even Miller's experiment has been criticized for not simulating actual conditions on the early Earth.)

Nucleotides arrayed along the backbone of the DNA molecule form triplets called codons. In the language of the genetic code, these three-digit codons are commands that the cell interprets when constructing proteins. There are codons that signify start commands, stop commands, and codons for signaling each of the 20 amino acids used in proteins. They convey information by virtue of their sequence, not their chemical properties. DNA is like written language in that respect. For example, both s-a-l-t and l-a-s-t contain the same four letters, but convey different meanings based on their sequence alone. When sequenced correctly, nucleotides in the DNA instruct the cell to use its molecular machinery to link amino acids into proteins. The precise sequence of these amino acids, specified by the DNA, is crucial to ensuring that a protein is properly assembled and functional. That's how DNA embodies functional information.

In 1953 Watson and Crick described the double helical structure of DNA but no one has yet explained the origin of the information DNA contains. This creates a problem for those trying to explain the origin of life as a result of undirected processes. If the nucleotide sequence in the DNA were different, proteins wouldn't function, or they probably would not even get built to begin with. "So the information in DNA and its companion molecule RNA is a huge stumbling block for evolution," Meyer said.

He mentioned the famous Dawkins comment that biology is the study of complex things that appear to have been designed for a purpose. But we are talking about actual, not apparent design. No undirected chemical process that we know of can produce the information necessary to account for the origin of the first living cell.

Just as useful computer code comes from programmers, so functional information comes from intelligence. It comes from mind, said Charles Thaxton. Darwin's geologist friend, Charles Lyell, said that in trying to understand events in the remote past, we should look for causes now in operation. Mind fits that bill. Intelligence, or mind, or conscious activity, is the only known cause of the kind of sequence-specific, information-rich code that we see in biology.

Thus, we infer that the ultimate origin of biological information is best explained as proceeding from the design of an intelligent agent or agents. All other proposed explanations have failed; none cites a cause that is known to produce information.

Meyer said a few words about the reaction to Signature in the Cell. No one has demonstrated that there is a better chemical evolutionary explanation for the appearance of information, said Meyer. Some critics insist that Darwinian mechanisms can get the job done. But processes such as natural selection can't take place until life is already up and running. "Invoking biological evolution is to miss the whole point of the book," Meyer said.

Until we have a living and self-replicating cell, we have no way of introducing natural selection into the picture. "Nothing I've said to this point challenges Darwin directly," Meyer added. But then Darwin himself never successfully refuted the design argument. Nor do those who cite Darwinian processes.

At this point, Meyer transitioned to the second part of his talk. Here he explained that biological evolutionary theory, which "attempts to explain how new forms of life evolved from simpler pre-existing forms" also faces formidable difficulties. In particular, the modern version of Darwin's theory, or neo-Darwinism, also has an information problem. The mutation and natural selection mechanisms have failed to explain the origin of the new information necessary to build fundamentally new forms of life, or even just new proteins.

Before going on, Meyer distinguished three meanings of evolution. First "change over time," which no one disputes. Second, the claim that this change has occurred in a continuous way, giving us the "branching tree picture" that was the only diagram in The Origin of Species. Third we have natural selection with mutation, or "copying errors in the DNA." They are analogous to copying errors in digital code.

The errors change the information in the DNA, supposedly providing the grist for natural selection. "We are expected to believe that random mutations provide the new information that is necessary to build new proteins, new cells, new traits, organs and tissues that arise in the process of evolution," Meyer said. But can natural selection generate enough information to build new forms of life?

In a "sneak preview," Meyer said his next book would be about the Cambrian explosion -- the geologically sudden appearance of most of the major animal forms and body designs. It is a dramatic event in the history of life; new body plans -- for example arthropods, chordates and brachiopods -- appeared suddenly about 530 million years ago. There's a geological stratum in China where many new animal phyla appear within a few million years. This pattern doesn't match that "continuously branching tree" that Darwin drew. Nothing that can plausibly be called a precursor appears in the strata below the Cambrian.

More importantly, the same information problem arises: What would it take to build one of those new body plans? "You need a big instruction set, just for one body part." The trilobite has a compound, lens-focusing eye. "Each new cell for each new tissue had dedicated proteins. And the proteins in turn need instructions for them to be built." It's hard to believe that mutation could generate the new information required.

Random changes in DNA are supposed to generate new sections of code. But how? Meyer discussed the 1966 Wistar Institute symposium in which MIT mathematicians and others expressed doubts about the plausibility of the story.

We have already seen that DNA and software must have something called "sequence specificity" if they are to provide functional information.

"What we know from all codes and languages is that when we are dealing with specificity of sequence as a condition of function, random changes degrade function much faster than they ever come up with something new," Meyer said.

There's a combinatorial problem. A bike lock with four dials and ten digits gives 10,000 possibilities, only one of which opens the lock. Ten dials would give us 10 billion possibilities. But the protein alphabet has 20 possibilities at each site and the average protein has about 300 amino acids in sequence.

Meyer explained that, in the case of proteins, unlike the bike lock, there are many functional arrangements of amino acids among the possible combinations. Nevertheless, the ratio of functional sequences to the total number remains prohibitively small. How rare are the functional sequences? A colleague of Meyer's, Doug Axe, with a PhD from Caltech, looked into this question while doing research at Cambridge University.

Using the method of Site Directed Mutagenesis, Axe found the ratio of functional to all possible sequences for a protein 150 amino acids in length to be an absurdly small 1 to 10⁷⁴. That search space is larger than the number of atoms in the Milky Way galaxy. So we have a "hideous search problem." Multiplying that low probability by the total number of organisms reduces the problem somewhat, but not enough to make it remotely plausible that mutation and natural selection could produce one functional protein of modest length during entire history of life on earth.

Not just any old jumble of amino acids makes a protein. Similarly, chimps typing at keyboards will have to type for a long time before they get a complete, error-free, meaningful sentence of 150 characters. They'll get letters of the alphabet because they use typewriters. The problem is they have to get the letters in the right order. The required sequence is both complex and specified.

"Lots of biophysicists are aware of the problem," Meyer said. "We have a small needle in a huge haystack. It's a problem that neo-Darwinism has not solved. And notice that there's a mathematical rigor to this which has not been a part of the so-called evolution-creation debate."

Meyer concluded by emphasizing that there is a huge disparity between the alleged consensus about contemporary evolutionary theory and the many formidable, and increasingly quantifiable, problems with the theory that are known in the technical scientific literature.

We may live at the centre of the universe(so to speak) after all

In Search of Circumstellar Habitable Zones

Daniel Bakken November 25, 2014 4:38 AM 

Editor's Note: As a series at ENV, we are pleased to present "Exoplanets." Daniel Bakken is an engineer who teaches astronomy at the college level, and an entrepreneur in compound semiconductor crystal growth. In a series of articles he critically examines recent claims about exoplanets beyond our solar system, asking whether our own planet Earth is a rarity, or common, in the cosmos.

In the search for habitable planets, the circumstellar habitable zone is the spherical shell environment defined as habitable in a stellar system. Astrobiologists have used the term for many decades. This shell encompasses the distance at which a planet in a fairly circular orbit could maintain liquid water on its surface. We will start here for historical reasons, but broader environments also must be considered. The galactic neighborhood factors in, as does the galactic habitability zone. On a larger scale still, there is also a cosmic habitable age, needed to produce the necessary elements for life and life-supporting planets. These factors cannot be completely separated, and all of cosmic history also plays an important role.

The primary problem with liquid water on a planet's surface is getting the planet in the right range for temperature and pressure.¹ We now know this concept needs to be modified to what is called the circumstellar continuously habitable zone. This zone allows a body to have liquid water not just at one point in time, but over several billion years.² After all, it has required nearly four billion years of stable conditions on Earth for intelligent technological life to appear. François Forget recognized the difficulty in his paper on this topic:

I will not discuss here the inherent difficulty of biological evolution and the fact that "a lot of luck" may have been required to make animals (Ward and Brownlee, 2000, Carter, 2008). Nevertheless, it is striking that when assessing the odds of having planets harboring complex or even intelligent life like in the Drake equation, one must estimate the frequency of planets which can remain continuously habitable for billions of years.³

This is much more restrictive. For a body to be continuously habitable for this length, many other factors come into play.

In order to understand the complexities of the CHZ, let's look at it in more detail. The inner boundary of the CHZ can be defined in two different ways. It can be set by the "moist greenhouse" effect, where water is transported by energy from the host star into the upper atmosphere, where it is broken up by ultraviolet light into hydrogen and oxygen. The hydrogen has enough energy to be lost to outer space, slowly drying out the planet. The other defining inner limit of the CHZ is the runaway greenhouse effect, where water vapor acts as a greenhouse gas, and eventually heats the surface to the point it cannot support liquid water.⁴

The outer boundary can be defined by the maximum possible carbon dioxide-caused greenhouse effect that can allow water in the liquid state on the surface, without creating so many carbon dioxide clouds that reflectivity of the planet increases to the point where it cancels out the greenhouse effect.⁵ As far as the outer edge of our sun's habitable zone, the classical model suggests the Earth is already on the outer edge to avoid runaway glaciation.⁶ But as Forget says, "In reality, on Earth there is a long-term stabilization of the surface temperature and CO₂ level due to the carbonate-silicate cycle."⁷

To increase the size of the habitable zone, and thus the chances for finding habitable planets, it has been suggested that planets with masses between one and ten times that of Earth (called super-Earths in the literature)⁸ with a H₂-He (hydrogen-helium) thick atmosphere, could have greenhouse effects that would enable habitable zones out to ten astronomical units (AU).⁹ An AU is an astronomical unit, the average Earth-Sun distance. That is ten times further out than the Earth presently orbits the Sun. However, models show that the H₂-rich atmosphere will either rapidly escape to space after the planet forms, or remain thick, preventing liquid water with high surface pressure.¹⁰ We must also take account of the fact that the percentage of planets left with exactly the right atmospheric pressures to allow habitable temperatures after the early stages of atmospheric erosion is likely to be very small.¹¹ Although these systems could transition through an appropriate environment, the periods would be thousands to a few millions of years, too short for advanced life over the long haul.

Also to be considered is that animal lung systems can only efficiently work within a narrow range of pressure. The atmospheric pressure cannot vary much from Earth's, which is dependent on the planet's mass, or else the efficient mammalian lung system as we know it will not work.¹² Imagine a world where the atmospheric pressure limits intelligent life to the most basic activities of life, because it requires too much energy to do other productive work. The higher atmospheric pressure increases the viscosity of the air, and without energy to push above and beyond mere survival, any alien life's ability to produce technology would be nil.

Venus and Mars are candidates in our solar system to test these models. The most restrictive CHZ models set the boundaries for our Sun at 0.95 AU for the inner and 1.37 AU for the outer one. The Earth couldn't be much closer to the Sun than it is, but it enjoys, according to these models, the near-maximum energy from the Sun that life can utilize.¹³ A further study found that the inner boundary may be even more severe. It looks like the inner limit to avoid a moist greenhouse loss of water is 0.99 AU -- almost exactly where the Earth sits in its orbit.¹⁴

The circumstellar habitable zone was historically calculated with constant circular orbits and constant energy flux, but newer studies include other variables that would certainly affect a planet's habitability. Previous to 2011, most studies of habitable atmospheres were conducted with easy to model one-dimensional steady state radiative convective parameters that simulated average planet-wide conditions. These 1D models are too simple to gauge properly the habitability of a planet. Utilizing more sophisticated 3D models with time-based changing parameters, the actual habitability of a planet can be approximated much better. These also can give local habitability data by including day-night cycles, and seasons. They can also model the impact of clouds on habitability for the first time, which is important, since clouds can affect the boundaries of a star's habitable zone.¹⁵

These more complex 3D models can also simulate with much better precision what can happen to carbon dioxide and water on a tidally locked planet, or one with high eccentricity or obliquity. Some planets could have liquid water that are further out than the classical models suggest if they have high levels of carbon dioxide.¹⁶ However, these high pressures would likely not enable efficient lungs such as exist on the earth, making it difficult to develop technological civilizations.

The other outcomes of these models seldom suggest habitable climates, and it seems that these complex simulations bring with them more reasons for pessimism in the search for habitable worlds. These studies include factors such as gravitational interactions, stellar winds, and particle radiation, UV radiation, and luminosity variations. Many other factors probably also come into play, but for the stellar habitable zone studies these are the most recently investigated.

Next up: The Right Kind of Star.

References Cited:

(1) Forget, "On the Probability of Habitable Planets," 180.

(2) Gonzalez, "Setting the Stage for Habitable Planets," 38.

(3) Forget, "On the Probability of Habitable Planets," 180.

(4) Gonzalez, "Setting the Stage for Habitable Planets," 37-39.

(5) Ibid., 37.

(6) Forget, "On the Probability of Habitable Planets," 182.

(7) Ibid., 6.

(8) Dimitar Sasselov, The Life Of Super-Earths: How the Hunt for Alien Worlds and Artificial Cells Will Revolutionize Life on Our Planet (New York: Basic Books, 2012), 64.

(9) Forget, "On the Probability of Habitable Planets," 183.

(10) Ibid., 6.

(11) Robin Wordsworth, "Transient conditions for biogenesis on low-mass exoplanets with escaping hydrogen atmospheres," Icarus 219 No. 1 (May 2012): 276-279.

(12) Michael J. Denton, Nature's Destiny: How The Laws Of Biology Reveal Purpose In The Universe(New York: The Free Press, 1998), 128.

(13) Gonzalez, "Setting the Stage for Habitable Planets," 37.

(14) Ibid., 37.

(15) Forget, "On the Probability of Habitable Planets," 184.

(16) Ibid.