On ID as zombie apocalypse.

Is the Market for Articles that Ask "Is Intelligent Design Dead?" Dead?

David Klinghoffer 

and theistic evolutionists keep pumping them out, as they've done for ten years now since the Dover decision. Yet all these numerous funeral processions later, here we still are. 

Here's a partial list of contributions:

• "Is Intelligent Design Dead?" (American Policy Roundtable 2006)
• "Is Intelligent Design Dead?" (Annals of Spacetime 2007)
• "Intelligent Design is Dead! Long Live Creationism?" (Vassar Alumnae/i Quarterly 2007)
• "Twenty years after Darwin on Trial, ID is dead" (Jason Rosenhouse 2011)
• "Jason Rosenhouse pronounces intelligent design dead" (Jerry Coyne 2011)
• "Intelligent Design Is Dead: A Christian Perspective" (Paul Wallace, Huffington Post 2012)
• "Paul Wallace Says, 'Intelligent Design Is Dead'" (Internet Monk, 2012)
• "Is 'intelligent design' dead since everybody realized it's just good old creationism?" (Yahoo Answers 2013)
• "Intelligent Design: Still Dead" (Jason Rosenhouse 2014)

Back in 2012, a person identified only as RJS wrote at the blog Jesus Creed, "Is Intelligent Design Dead?" Now RJS is back with more musings at the same venue, and asking the same question, "Is Intelligent Design Dead?" RJS begins:

A decade ago Intelligent Design with a capital I and a capital D was a hot topic. A major trial testing the teaching of the ID in Pennsylvania was decided in late 2005 and Stephen C. Meyer's massive book Signature in the Cell was published in 2009. It was a common topic in evangelical churches -- viewed as a way to combat the evil influence of evolution. Quite frankly, it was a topic I was ready to see disappear. The controversy was tainting most conversations about Christianity in my circles at the University.

"Tainting conversations"? Why? He doesn't say.

RJS quotes a religion professor at Pepperdine University, Ron Highfield, who's looked into ID a bit. He concludes on Highfield's authority that intelligent design isn't "a particularly useful scientific or theological approach."

Not "useful"? Toward what end? What about "true," "serious," "honest"? But fine, then what wouldbe "useful"? This, says RJS:

[T]he best empirical evidence for intelligence isn't found in the pattern of DNA but in the existence of intelligence in the universe. This is complexity at its highest. In fact, the sciences that look for intelligence ... forensic science, information theory, cryptography etc. ... rely on intelligence to detect intelligence. "Only a mind can detect information or the activity of another mind." (p. 163)

Intelligent design theory as an empirical science alone cannot get us to a designer. It cannot offer an alternative to biological evolution. There is no reason to set it up against modern science as science. On the other hand, as a philosophical argument -- reasoning from intelligence to intelligence -- it has something to offer.

RJS allows that as a Christian he believes "the world is intelligently designed for a purpose." What he rejects is recognizing objective, scientific evidence of that. If I follow the line of reasoning correctly, he would rather infer "intelligence" from "intelligence." Once again quoting the indispensable Ron Highfield:

Had [William] Dembski argued from the mind's perception of the pervasive presence of intelligible reality with in the universe, in itself and other human minds, in biological structures, in cosmological laws and in the micro world of subatomic structures to the existence of a cosmic mind, his argument would demand attention. It would be built on a primitive , undeniable and universal human experience. (p. 164)

What? I don't want to give RJS, or Ron Highfield, less credit than they deserve, but that makes no sense. Because we experience minds at the human level, therefore...intelligent design? That's an "undeniable" argument that would "demand attention"?

Guys, please. You may notice that everyone dramatically heralding the demise of the ID movement does so with his own idiosyncratic justifications, often leaning on the vaporous authority of someone else who said it first, and never taking note of the excellent decade that ID has in fact enjoyed since Dover.

With the religious critics in particular, it's hard to resist the suspicion that it's easier to say "ID Is Dead" than it is to grapple with the relevant science, which can admittedly be challenging. RJS seems to regard the sheer volume of Stephen Meyer's "massive" book as off-putting. (It's actually not that massive.) 

But this is not surprising. If you write for a blog called Jesus Creed, it's probably not because of your interest in biology.

And I sympathize. Not everyone can picture himself cracking open a "massive" science tome. But then at least when someone asks you "Is ID Dead?," or when it occurs to you to write an article with that title, have the humility to say, "I don't have the slightest idea."

On the Herods:TheWatchtower Society's commentary.

the Days of Herod the King”

IN AN attempt to kill the infant Jesus, Herod the Great, king of Judea, sent envoys to massacre all baby boys in Bethlehem. History records numerous events that took place “in the days of Herod the king,” events that throw light on the context of Jesus’ life and ministry.—Matthew 2:1-16.

What made Herod want to kill Jesus? And why was it that when Jesus was born, the Jews had a king, but when Jesus died, Pontius Pilate, a Roman, governed them? To get the full picture of Herod’s role in history and to understand why he is important to Bible readers, we need to look back several decades before Jesus’ birth.

Power Struggles in Judea

In the first half of the second century B.C.E., Judea was ruled by the Syrian Seleucids, one of the four dynasties that formed after the breakup of the empire of Alexander the Great. However, in about 168 B.C.E., when the Seleucid king attempted to replace worship of Jehovah with the cult of Zeus at their temple in Jerusalem, the Jews, led by the Maccabee family, revolted. The Maccabees, or Hasmoneans, ruled Judea from 142-63 B.C.E.

In 66 B.C.E., two Hasmonean princes, Hyrcanus II and his brother Aristobulus, fought for succession to the throne. Civil war ensued, and both sought the aid of Pompey, a Roman general who at the time was in Syria. Pompey jumped at the chance to interfere.

The Romans, in fact, were extending their influence eastward, and by this time, they controlled much of Asia Minor. A series of weak rulers in Syria, however, had allowed the area to sink into anarchy, menacing the peace that the Romans desired to maintain in the East. So Pompey had stepped in to annex Syria.

His solution to the Hasmonean quarrel was to back Hyrcanus, and in 63 B.C.E., the Romans stormed Jerusalem to install their nominee. Hyrcanus, however, was not going to be an independent ruler. The Romans now had a foot in the door and were not about to remove it. Hyrcanus became a Roman ethnarch, one who ruled by the grace of the Romans, dependent on their goodwill and support to retain his throne. He could administer internal affairs as he wished, but in foreign relations, he had to conform to Roman policy.

The Rise of Herod

Hyrcanus was a weak-willed ruler. He was supported, though, by Antipater, an Idumean and the father of Herod the Great. Antipater was the power behind the throne. He kept restless Jewish factions at bay and soon took effective control of Judea. He helped Julius Caesar fight his foes in Egypt, and the Romans rewarded Antipater by raising him to the position of procurator, answerable directly to them. Antipater, in turn, appointed his sons, Phasael and Herod, as governors of Jerusalem and of Galilee respectively.

Antipater taught his sons that nothing could be achieved without Rome’s consent. Herod remembered that lesson well. Throughout his career, he juggled the demands of his Roman patrons with those of his Jewish subjects. He was aided by his skills as an organizer and a general. On his appointment as governor, 25-year-old Herod promptly won himself the admiration of Jews and Romans alike by vigorously eliminating bands of bandits from his territory.

After rivals poisoned Antipater in 43 B.C.E., Herod became the most powerful man in Judea. Yet, he had enemies. The Jerusalem aristocracy considered him a usurper and sought to persuade Rome to remove him. The attempt failed. Rome was loyal to Antipater’s memory and valued his son’s abilities.

Made King of Judea

Pompey’s solution to the Hasmonean succession crisis some 20 years earlier had embittered many. The unsuccessful faction repeatedly attempted to retake power, and in 40 B.C.E., they succeeded with the help of Rome’s enemies, the Parthians. Exploiting the chaos created by civil war in Rome, they invaded Syria, deposed Hyrcanus, and installed an anti-Roman member of the Hasmonean family.

Herod fled to Rome, where he received a warm welcome. The Romans wanted the Parthians ousted from Judea and the territory returned to their control with an acceptable ruler. They needed a reliable ally and saw Herod as their man. The Roman Senate thus crowned Herod king of Judea. In an act symbolic of the many compromises that Herod would have to make to maintain his grip on power, he led a procession from the Senate to the temple of Jupiter, where he sacrificed to pagan gods.

Helped by Roman legions, Herod defeated his enemies in Judea and claimed his throne. His revenge upon those who had opposed him was brutal. He eliminated the Hasmoneans and the Jewish aristocracy who had supported them, as well as any others who chafed at having a friend of the Romans rule over them.

Herod Consolidates His Power

In 31 B.C.E. when Octavius emerged as the undisputed ruler of the Romans by defeating Mark Antony at Actium, Herod realized that his long-standing friendship with Mark Antony would be viewed with suspicion. So Herod hastened to assure Octavius of his loyalty. The new Roman ruler, in turn, confirmed Herod as king of Judea and enlarged his territories.

In the years that followed, Herod stabilized and enriched his kingdom, transforming Jerusalem into a center of Hellenistic culture. He embarked upon great construction projects—building palaces, the port city of Caesarea, and grand new edifices for Jerusalem’s temple. All the while, the focus of his policy and the source of his strength were friendship with Rome.

Herod’s control over Judea was total; his authority, absolute. Herod also manipulated the high priesthood, appointing to this office whomever he wished.

Murderous Jealousies

Herod’s private life was turbulent. Many of his ten wives wanted one of their sons to succeed his father. Palace intrigues aroused Herod’s suspicions and his cruelty. In a fit of jealousy, he had his favorite wife, Mariamne, executed, and he later had two of her sons strangled for alleged plots against him. Matthew’s account of the Bethlehem massacre thus harmonizes with what is known of Herod’s temperament and his resolve to eliminate possible rivals.

Some say that, aware of his own unpopularity, Herod was determined that his death should be met with national mourning rather than rejoicing. In a scheme to achieve that goal, he arrested Judea’s leading citizens and ordered that they all be executed when his own death was announced. The order was never carried out.

The Legacy of Herod the Great

On Herod’s death, Rome decreed that Archelaus succeed his father as ruler of Judea and that two other sons become independent princes, or tetrarchs—Antipas over Galilee and Perea, Philip over Iturea and Trachonitis. Archelaus proved unpopular with his subjects and masters. After a decade of his ineffectual dominion, the Romans removed him and appointed their own governor, the predecessor of Pontius Pilate. In the meantime, Antipas—whom Luke simply calls Herod—and Philip continued to govern their own tetrarchies. This was the political situation at the start of Jesus’ ministry.—Luke 3:1.

Herod the Great was an astute politician and a ruthless murderer, probably his worst act being his attempt to kill the infant Jesus. Examining Herod’s historical role is useful for Bible readers—it helps illuminate key events of the period, explains how the Romans became rulers of the Jews, and sets the stage for Jesus’ earthly life and ministry.

On why linking Darwin to Hitler matters to Darwinists.

Why My Critics Care So Much About the Darwin-Hitler Connection

Richard Weikart

published my earlier historical works, From Darwin to Hitler: Evolutionary Ethics, Eugenics, and Racism in Germany (2004) and Hitler's Ethic: The Nazi Pursuit of Evolutionary Progress. Hardly anyone, however, bothered to engage the arguments, except for Robert Richards at the University of Chicago, whose critique of my position is riddled with errors, not only of interpretation, but also of basic facts.

As I demonstrate in my newly released book, The Death of Humanity: And the Case for Life, there is a fundamental tension between many Darwinists' claim that morality is an evolved trait -- thus having no objective reality -- and their moral indignation toward Hitler (and toward me for explaining how Darwinism informed Hitler's ideology).

To be sure, I have encountered some true believers in Darwinism who have told me that their Darwinian-inspired moral relativism leads them to the conclusion that Hitler was neither right nor wrong. I once held a conversation with a philosophy graduate student who defended moral relativism on Darwinian grounds. After I pressed him to see if he was willing to be relativistic about Hitler's atrocities, he uttered the stunning words, "Hitler was OK."

Maybe you think this student was just off his rocker. However, the leading evolutionary biologist and world famous atheist Richard Dawkins took a similar position in an interview, where he was being questioned about his moral relativism. Dawkins asked, "What's to prevent us from saying Hitler wasn't right? I mean, that is a genuinely difficult question." If this is a tough moral question for Dawkins, he should stop pontificating about how religions are "the root of all evil," especially since he doesn't believe that evil actually exists!

Most Darwinists, however, including those who believe in the evolution of morality, do not have consciences as dead as Dawkins, so they are genuinely outraged by the historical connections between Darwin and Hitler. They consider Hitler truly evil, and they don't want their positive image of Darwin tarnished by any association with this evil man.

However, why do they care about this at all? If they believe, as many do, that morality is simply "an illusion fobbed off on us by our genes," as evolutionary biologist E.O. Wilson and philosopher Michael Ruse famously put it, then what makes the illusions of some people superior to Hitler's illusions? Why do everything possible -- even denying obvious historical facts -- to obscure the historical linkages between Darwin and Hitler? I have a hunch that at some level they recognize that their evolutionary account of morality is inconsistent with reality.

In The Death of Humanity: And the Case for Life, I expose many of the inconsistencies within secular philosophies, such as Darwinism, materialism, positivism, and many others.

Dr. Weikart is professor of history at California State University, Stanislaus, and Senior Fellow at Discovery Institute's Center for Science and Culture.

On the alt-right and the monkey on Darwinism's back

Evolution and the Alt-Right

David Klinghoffer 

you know that a mostly online splinter called the "alternative right" or "alt-right" is currently a subject of bitter and voluminous indignation. At The Federalist today, Cathy Young has an interesting analysis ("You Can't Whitewash the Alt-Right's Bigotry"), taking issue with two other journalists at Breitbart who tried to explain the phenomenon in a sympathetic, even admiring manner.

There is great worry about the conservative brand image, and the alt-right figures prominently in that. Cathy Young's piece, you'll notice, has some intriguing references to evolution, "human biodiversity," "race-related genetic cognitive and behavioral differences," and related subjects. On that, she and other mainstream conservatives could have said much more. Though this has escaped focused attention, the alternative right draws heavily on themes of evolution-based racism. And that is significant.

Miss Young notes "retired California State University-Long Beach psychology professor Kevin MacDonald, who has some peculiar theories about Jews: namely, that Judaism is an 'evolutionary strategy' by which Jews seek dominance...It's 'The Protocols of the Elders of Zion' dressed up as evolutionary psychology."

Another writer cited by Young raises eugenic, or rather dysgenic, concerns:

"The Pro-Life Temptation" by Aylmer Fisher -- presumably a pseudonym stolen from the innocent British geneticist -- which cautions the alt-right against adopting an anti-abortion stance in knee-jerk opposition to liberals. The pro-life position is 'dysgenic,' since it encourages breeding by 'the least intelligent and responsible' women.

If you think you know where this is going, you're right. Fisher argues that, firstly, the pro-life position is "dysgenic," since it encourages breeding by "the least intelligent and responsible" women who are most likely to have abortions and who are "disproportionately Black, Hispanic, and poor."

Taken from the Radix Journal (more on it in a moment), that's ugly stuff and Miss Young does a service in pointing it out. In her article, our old nemesis John Derbyshire, scrubbed from National Review, makes an appearance, along with the alt-right "movement's online hubs such as Richard Spencer's AlternativeRight.com and Steve Sailer's VDARE." (Actually VDARE is edited by Peter Brimelow, not Steve Sailer, who has his own blog at another alt-right hotspot, The Unz Review. Once upon a time, I enjoyed editing them both as writers for National Review.)

But this is just the tip of the iceberg. We've reported here in the past on the evolutionary preoccupations of Derbyshire and another "race-realist" outlet, Jared Taylor's American Renaissance. But not till reading Cathy Young's post did I recognize that the mother lode of pseudo-conservative, pseudo-scientific racism is Richard Spencer's AlternativeRight.com, which as she points out has been rebranded as Radix Journal, "dedicated to the heritage, identity, and future of European people in the United States, and around the world."

Here, the vein of evolutionary thinking is particularly rich. We read, "Darwinian Evolution Revolutionized the Natural Sciences. The Social Sciences Have Been Immune for Too Long." In "What Is Identitarian Religion?," writer "Alfred W. Clark" tells of a "long-standing 'Trad Catholic' I know [who] told me recently that he had left the Church. [H]is 'conservative' priest had become obsessed with [among other things]...denouncing evolution because it's 'racist'." More:

And what of identitarian atheists and agnostics? Can they co-exist with identitarian religion? Since identitarian religion is not at odds with nature, and thus not at odds with evolutionary science, it does not threaten secular knowledge but offers itself as an additional societal glue.

Another writer wonders why few women seem enthusiastic about "race-realism":

The evolutionary basis for this doesn't seem too hard to figure out. As a prehistoric man, you have to decide the best way to find food and kill the members of the other tribe....

There is sympathy for eugenics, and much fretting about the "dysgenic menace." A writer notes an "antisocial Darwinism" where "Society favors the broken at the expense of the fixed. The result isn't so much that the fixed are crushed, but that the broken proliferate and become permanent dependents of the state." 

Richard Spencer shares his "Foreword to a new annotated edition of [racial eugenicist] Madison Grant's Conquest of a Continent [1933]," explaining that "Darwinism offers a compelling and rational justification for Whites to act on behalf of their ancestors and progeny and feel a shared since of destiny with their extended kin group."

Again, Alfred W. Clark asks, "What Is the #Altright?" He explains: 

Michael Brendan Dougherty recently called the alt-right "race obsessed". A better phrase might be: race realists. Most alt-righters actually take Darwinism seriously. (If you are at a loss of what "taking Darwinism seriously" means, you might want to read this book.) Young alt-righters are comfortable with modern science which shows that human biodiversity is a facet of life. The fact that so many today in Conservatism Inc. want either to ignore or deny human biodiversity, shows how untethered from reality modern conservatism has become. 

And much more along these lines. 

The Right has periodically sought to purge itself of tendencies like this, and it's engaged in such a purge right now. I prefer understanding to demonizing. Darwinian "conservatives" operate with a particular picture in mind of what a human being is -- a very different picture from the one posited by the Judeo-Christian tradition on which conservatism has drawn in the past. It's either man the animal or man in the image of an intelligent designer. Those are the choices.

From such a stark dichotomy, everything else is downstream. Recognizing as much would be a first step to restoring the health of a fractured and troubled movement.

Biology as tech/Biology as art III

Denton's Challenge: Are Leaf Shapes Adaptive?

Evolution News & Views

In his new book Evolution: Still a Theory in Crisis, Michael Denton provides a cavalcade of examples of non-adaptive forms in nature. On page 77, he points to angiosperm leaves as a case visible to everyone.

It is not only the unicellular world that abounds with what appear to be abstract formal patterns. Even on the most cursory and passing observation of some of the most familiar natural forms, such as the forms of leaves and the variety of phyllotactic arrangements that might be observed in any suburban garden, it is hard to resist concluding that a vast amount of botanical order serves no specific adaptive end. [Emphasis added.]

Our film Biology of the Baroque explores this further starting at 4:20, showcasing the wide variety of leaf shapes in a forest. Each plant has its own shape in the same environment, yet they live side by side. "But for Darwinian evolution to explain the shape of these leaves," the narrator states:

...there ought to be some reason why that specific shape caused one organism to live and another to die in a given environment. Yet there appears to be no functional reason why there are so many different leaf shapes. Much like Baroque architecture, these shapes seem extra, perhaps even decorative. They're not needed to survive. They are simply beautiful.

Enter Current Biology to the rescue of Darwinian functionalism. In "Evolutionary and Environmental Forces Sculpting Leaf Development," evolutionary botanists Daniel H. Chitwood and Neelima R. Sinha try to give adaptive reasons for leaf shape.

Leaf shape is spectacularly diverse. As a major component of plant architecture and an interface for light capture, gas exchange, and thermoregulation, the potential contributions of leaves to plant fitness are innumerable. Particularly because of their intimate association and interaction with the surrounding environment, both the plasticity of leaf shape during the lifetime of a plant and the evolution of leaf shape over geologic time are revealing with respect to leaf function. Leaf shapes arise within a developmental context that constrains both their evolution and environmental plasticity. Quantitative models capturing genetic diversity, developmental context, and environmental plasticity will be required to fully understand the evolution and development of leaf shape and its response to environmental pressures. In this review, we discuss recent literature demonstrating that distinct molecular pathways are modulated by specific environmental inputs, the output of which regulates leaf dissection. We propose a synthesis explaining both historical patterns in the paleorecord and conserved plastic responses in extant plants. Understanding the potential adaptive value of leaf shape, and how to molecularly manipulate it, will prove to be invaluable in designing crops optimized for future climates.

And so the debate is engaged. They want to explain the spectacular diversity of leaf shapes in an adaptive context. To accomplish this, though, they would have to relate unguided genetic mutations to selection at the molecular level. They admit up front that "The molecular mechanisms underlying such morphological diversity are even more poorly understood." 

Yet, patterns of correlation among leaf shapes across extant species, temperature and precipitation, and between fossil leaves and the paleoclimate, provide tantalizing glimpses into hypotheses unifying the development, evolution, and environmental plasticity of leaf shape with the possible functions it might confer.

They make the following suggestions for possible adaptive reasons for leaf shapes:

1. Plasticity: Shapes are not fixed in a particular species; leaves respond during development to environmental cues as they grow. "The leaves displayed by a plant at successive nodes reflect the developmental and environmental context of each leaf from initiation onwards."
2. Time: Leaf shape across geologic time is sensitive to the environment. "Relationships between leaf dissection and paleoclimates provide the most sweeping evidence of the responsiveness of leaf dissection to temperature and precipitation," they claim. As evidence, they point to studies that show "leaf serration can be used as a reliable index of the paleoclimate."
3. Climate: Leaf shape is plastic within one plant's lifetime and across geologic time, they say. "That plasticity within the lifetime of a single plant, extant species distributions, and correlations with the paleoclimate follow each other suggests an intimate relationship between leaf morphology and climate." 
4. Transpiration: "Paleoclimate correlations are focused on marginal serrations, which have been hypothesized as a constraint arising in thinner leaves more reliant on major veins, an adaptive feature allowing early season growth in deciduous forests, sites of increased transpiration, or that arise from hydathodes to maintain optimal leaf turgor." This is not true of all plants, however. "Similar plasticity in annuals observed in cold temperatures involves more than just serrations and cannot be explained by features exclusive to woody eudicots alone."
5. Sunlight availability: "Leaf dissection may simply reduce leaf area and affect canopy light interception...."
6. Economy: "....while also minimizing the distance between photosynthetic tissue and veins."
7. Heat transfer: "The potentially reduced leaf area in dissected leaves also facilitates heat transfer, reducing the boundary layer effect, but leaf shape likely also affects boundary layers independent of size."
8. Embryonic packing: "Leaf dissection may even reflect developmental constraintsrelated to packing in buds."
9. Compound leaves: "The possible functions of compound leaves have centered on the associated costs of producing a branch with many leaves vs. a complex leaf with many leaflets, and the premium put on vertical growth and 'branch shedding'."

All these hypotheses amount to little more than suggestions and just-so stories. They admit that none of them constitute a general law.

While hypotheses about the function of leaf shape are fascinating, they are numerous and cannot be generalized. Focusing on changes in shape common to evolutionary transitions into new environments, plastic responses in model organisms and patterns observed in the paleorecord may help narrow the field of relevant hypotheses to arrive at a more robust understanding of leaf morphology.

We ain't there yet, in other words. They leave the problem of leaf shape virtually unexplained, despite the fact that "Integrating natural variation in leaf shape with molecular pathways has always been a central goal of evolutionary developmental biology."

How much time to the Darwinians get? They've been thinking about this problem for 157 years at least. Must a functionalist story be served up, no matter how fraught with anomalies? Think again about the diversity in a forest, all these leaf shapes coexisting in the same environment. Where is a general law that would make them all trend toward the same shape? There is none. The diversity is still spectacular.

Denton's book is filled with other examples. "It's OK if it's just a maple leaf," he says in the video:

You can perhaps pass over the maple leaf, but if non-adaptive order, like the maple leaf, permeates the biological world, and if a lot of the taxa-defining novelties seem to be non-adaptive, you now have a nightmarish scenario when the fundamental assumption of Darwinism is that all these novelties in nature are adaptive suddenly looks very insecure.

Intelligence is a cause that can make things beautiful and diverse. After 157 years, its explanatory robustness is doing a much better job than fruitless attempts to seek "tantalizing glimpses into hypotheses" in a search for "possible functions" in the adaptationist program.

Darwinism vs. the real world XXV

Keeping Cool, Warming Up: Appreciating the Body's Temperature Control System

Howard Glicksman

Editor's note: Physicians have a special place among the thinkers who have elaborated the argument for intelligent design. Perhaps that's because, more than evolutionary biologists, they are familiar with the challenges of maintaining a functioning complex system, the human body. With that in mind, Evolution News is delighted to offer this series, "The Designed Body." For the complete series, see here. Dr. Glicksman practices palliative medicine for a hospice organization.

As I showed in the last two articles in this series, heat is the transfer of energy from one object to another, whereas temperature is a measure of an object's internal energy or its degree of random molecular motion. The body must control the temperature of its internal organs (core temperature) because the molecules that make up the cells and perform the functions of life work best within a certain temperature range: 97o-99oF (36o-37oC). 

When it comes to heat and temperature, the laws of nature make two demands on the body. First, they demand that heat be released when energy is used to do work. At complete rest, the body releases a minimum amount of heat from its basal metabolic rate (BMR), which is mostly under control of thyroid hormone. However, since the body must remain fairly active to survive, it releases even more heat due to this work. And second, the laws of nature demand that a warmer object transfer heat energy to a cooler one when they come in contact with each other. Sit in cold water or a hot sauna and your body will either lose heat to, or gain heat from, its surroundings. 

In summary, the body's core temperature is determined by how much heat it produces through metabolism, whether it is at complete rest or not, and how much heat it loses to, or gains from, its environment. My last article looked at how the body, through thyroid hormone regulation, takes control of the BMR to help keep the core temperature within the normal range. However, there are other very important mechanisms the body uses to take control to keep the real numbers of core temperature where they need to be to survive within the laws of nature.

Any activity causes the body to use more energy and release more heat, above and beyond the level of the BMR. And since the body is always in contact with its surroundings (usually air, but sometimes water), it is always losing or gaining heat from its environment. Since these changes can take place rapidly, the body must have the ability to react quickly enough to correct the situation and keep its core temperature under control. In other words, besides using thyroid hormone to control the BMR, moment-to-moment thermoregulation must take into account, not only the heat released by the body's activity, but also the heat lost to, or gained from, its surroundings. This requires all three control components. 

The first thing you need to take control is a sensor to detect what needs to be controlled. The body has two different sets of temperature sensors which are called thermoreceptors. There are peripheral thermoreceptors in the skin that detect either hot or cold. Their main function is to warn the body when it is being exposed to very high or very low temperatures which may result in tissue damage (thermal burn or frostbite). In addition, the body has central thermoreceptors, which detect the core temperature, and are located within the chest, the abdomen, and the hypothalamus.

The second thing you need to take control is an integrator that can take the data it receives from the sensors, compare it with a standard, decide what must be done, and then send out orders. The hypothalamus is the integrator for core temperature control. Currently, we don't fully understand how it knows what the proper core temperature should be for survival. It is thought that the hypothalamus acts like a thermostat and keeps the body's core temperature around a set-point, which for most healthy people is 97o-99oF (36o-37oC). 

If the core temperature rises above the set-point, the hypothalamus sends out messages to limit heat production and promote heat loss. If the core temperature drops below the set-point, the hypothalamus sends out messages to promote heat production and limit heat loss. Besides sending messages to make you aware of being too hot or too cold, the hypothalamus also uses neurohormones in the sympathetic nervous system to keep moment-to-moment control of your core temperature. 

The third thing you need to control something is an effector that can do something about the situation. When it comes to thermoregulation, the effectors the body uses can either be voluntaryor involuntary. 

When the hypothalamus makes you conscious of a significant rise or fall in the core temperature, making you feel too hot or too cold, you can voluntarily do something to try to correct the situation. If you are too hot you can reduce the amount of heat your body produces by stopping your present activity and coming to a complete rest. You can remove some of your clothing to allow the heat to leave your body easier. You can get out of direct sunlight to prevent its heat from warming you too much or turn on a fan or pour cold water on yourself to help your body lose more heat. In contrast, if you are too cold, you can increase the amount of heat your body produces by increasing your activity level, like rubbing your hands together, stamping your feet, or moving around more. You can put on heavier clothing to prevent your body from losing too much heat. You can go out into the sunshine or stand near something hot, like a fire or wood stove or jump into a hot tub so you can receive more heat. 

Besides doing things that promote heat loss and limit its production when we feel too hot or promote heat production and limit heat loss when we feel too cold, our body has several involuntary (automatic) mechanisms in place to achieve this as well. 

When, despite all efforts, the body is still too cold, the hypothalamus can activate two other effectors to promote heat production. One of them is to make the muscles shiver. This shaking activity does not move the bones to perform work, but instead produces more heat for the body. The other effector for increased heat production causes the release of certain hormones to increase the body's metabolic rate and release more heat from cellular respiration and fat. 

However, the main effector for thermoregulation is the skin. The skin is the outer layer of the body, which is in direct contact with its surroundings. It is made up of many different types of cells that together serve to protect the body from many aspects of nature, like friction, chemicals, and microbes. It is the unique nature of the skin's circulation and the presence of millions of sweat glands that provide it with the equipment to help the body control its core temperature. 

The blood flow within a given tissue or organ is usually related to its metabolic needs -- in other words, how hard it is working. However, this is not the case for the skin. In fact, the amount of blood flow in the skin is usually much more than its metabolic needs demand. The skin, particularly in the hands, feet, ears, nose, and lips, has blood vessels that allow direct connections between the arterial and venous systems. These arterio-venous connections facilitate rapid blood flow by shunting blood directly from the arteries to the veins while bypassing the capillaries. Being so close to the surface of the body, the warm blood that travels in the circulation of the skin has a tendency to cause the body to lose heat by radiation and conduction aided by convection. In general, the more blood flow to the skin surface, the more heat loss from the body, and the less blood flow to the skin surface the less heat loss. 

When the body's core temperature changes, the hypothalamus adjusts the amount of messages it sends along the sympathetic nerves to the muscles surrounding the blood vessels in the skin. These nerve impulses result in the release of a neurohormone called norepinephrine. Norepinephrine attaches to specific receptors on these muscles and tells them to contract. When the body's core temperature drops so that you feel cold, the hypothalamus responds by sending out more messages along these sympathetic nerves, which makes them release more norepinephrine. More norepinephrine makes the blood vessels in the skin contract more. This results in less blood flow to the skin surface and less heat loss from the body. 

When the body's core temperature rises so that you feel hot, the hypothalamus responds by sending out fewer messages along these sympathetic nerves, which causes the release of less norepinephrine. Less norepinephrine makes the blood vessels in the skin relax more. This results in more blood flow to the skin surface and more heat loss from the body by radiation and conduction aided by convection. 

In addition, the skin has millions of sweat glands that can release perspiration onto its surface. This promotes further heat loss by evaporation as the water on the skin picks up heat from the body and is turned into water vapor. The hypothalamus triggers sweating through the sympathetic nerves, but instead of using norepinephrine as the chemical messenger, it uses a neurohormone called acetylcholine. 

Acetylcholine attaches to specific receptors on the sweat glands to turn them on. When the body's core temperature rises and you feel hot, the hypothalamus sends out more messages along the sympathetic nerves that supply the sweat glands, making them release more acetylcholine. More acetylcholine makes the sweat glands secrete more perspiration. This results in more heat loss from the body by evaporation. When the body's core temperature drops so that you feel cold, the hypothalamus responds by sending out fewer messages along the sympathetic nerves that supply the sweat glands, making them release less acetylcholine. This makes the sweat glands secrete less perspiration, resulting in less heat loss from the body. 

In summary, the body's control of its core temperature involves not only thyroid function and the BMR, but also the sympathetic nervous system. By necessity, life is a dynamic process in which the body must stay active and internally produce heat while at the same time externally losing or gaining it from its surroundings. When the hypothalamus receives data from the central thermoreceptors, compares it to the set-point, and determines that the body is too hot or too cold, it tells the conscious mind to do something to try to correct the situation. In addition, it sends out messages along sympathetic nerves to the blood vessels and the sweat glands in the skin which either promotes or limits heat loss. The result is that the body is usually able to control its core temperature and thereby survive within the laws of nature. 

It would seem that the system the body uses for thermoregulation knows what it's doing. However, to do its job properly the hypothalamus needs (1) central thermoreceptors throughout the body to detect its core temperature, (2) the ability to adjust the messages it sends out along the sympathetic nerves based on the set-point using (3) norepinephrine for the blood vessels in the skin and (4) acetylcholine for the sweat glands which, to have an effect, need (5) norepinephrine and (6) acetylcholine receptors, respectively. If any one of these six parts were to be missing, or not working properly, the whole system would fail and the body would not be able to control its core temperature. Biochemist Michael Behe has described such a system, where the absence of any one part renders it useless, as irreducibly complex -- a hallmark of intelligent design. The system our body uses to control its core temperature demonstrates irreducible complexity. 

However, this is not enough to explain how human life can survive within the laws of nature. Real numbers have real consequences and, if the core temperature rises too high or drops too low, it causes severe impairment of enzyme activity and with it, the metabolism. When it comes to thermoregulation, the body would seem to have natural survival capacity because the hypothalamus seems to inherently know, not only what the thyroid hormone level should be, but alsowhat the set-point should be.

Next time, in the context of thyroid function, we'll look at what happens when the numbers don't add up as they should.