November 21, 1953 (a Saturday)

On this date, the 40-year-long hoax of the Piltdown Man ended when the British Museum revealed that it was a “perfectly executed and carefully prepared fraud.” The Piltdown forgery was conceived, planned and executed sometime between 1907 and 1911. The faux hominid skull was constructed from the remains of a recent human cranium, later shown to have been thickened by disease during the subject’s lifetime (thus giving the primitive look); half the lower jaw of an orangutan from which telltale parts had been removed and whose teeth had been filed to resemble worn human teeth; and a doctored canine tooth, probably from the same lower jaw. In all, 37 pieces of carefully selected bone and stone were involved, each altered and stained.

August 27, 413 B.C.E.

On this date, a lunar eclipse caused panic among the sailors of the Athens fleet in Sicily and eventually affected the outcome of the Peloponnesian War (431-404 B.C.E.). Just as the Athenian forces were ready to sail home from Syracuse, the Moon was eclipsed. The soldiers and sailors were frightened by this celestial omen and were reluctant to leave. Their commander, Nicias, described by the ancient Greek historian Thucydides as a particularly superstitious man, asked the priests what he should do. They suggested the Athenians wait for another twenty-seven days, and Nicias agreed. The Syracusans took advantage of this, and seventy-six of their ships attacked eighty-six Athenian ships in the harbor, beginning what has become known as the Second Battle of Syracuse. The Syracusans ultimately defeated the entire Athenian fleet and army in September and executed Nicias.

Why do I mention this footnote to the history of ancient Athens? It illustrates that the failure (or refusal) to recognize the natural causes of natural events, such as a lunar eclipse, may seem harmless but can have disastrous consequences.

August 17, 1771 (a Saturday)

On this date, Joseph Priestley began an experiment in which he discovered photosynthesis, although he did not give it that name. He described his experiment in 1772 in a paper entitled “Observations on Different Kinds of Air”:

…I flatter myself that I have accidentally hit upon a method of restoring air which has been injured by the burning of candles, and that I have discovered at least one of the restoratives which nature employs for this purpose. It is vegetation. In what manner this process in nature operates, to produce so remarkable an effect, I do not pretend to have discovered; but a number of facts declare in favour of this hypothesis…

One might have imagined that, since common air is necessary to vegetable, as well as to animal life, both plants and animal had affected it in the same manner, and I own that I had that expectation, when I first put a sprig of mint into a glass-jar, standing inverted in a vessel of water; but when it had continued growing there for some months, I found that the air would neither extinguish a candle, nor was it at all inconvenient to a mouse, which I put into it.

…Accordingly, on the 17th of August 1771, I put a sprig of mint into a quantity of air, in which a wax candle had burned out, and found that, on the 27th of the same month, another candle burned perfectly well in it. This experiment I repeated, without least variation in the event, not less than eight or ten times in the remainder of the summer.

References

• Allen, J.F. and W. Martin, “Evolutionary biology: Out of thin air,” Nature 445: 610-612 (8 February 2007)
  

June 5, 469 B.C.E.

Today is the estimated date of birth of the Greek philosopher Socrates. He is best known outside philosophy for being condemned to death by an Athenian people’s court and choosing to die by drinking hemlock. He had been charged with impiety and with corrupting Athenian youth through his teachings and had been given the opportunity to go into exile. However, he chose to die as sentenced because he believed he would otherwise dishonor the agreement he had willingly made to abide by the laws of Athens.

Perhaps his most important contribution to Western thought is his dialogical method of inquiry, known as the Socratic Method or method of elenchos, which he largely applied to the examination of key moral concepts such as the Good and Justice, concepts used constantly without any real definition. It was first described by Plato in the Socratic Dialogues. For this, Socrates is customarily regarded as the father of political philosophy and ethics or moral philosophy, and as a fountainhead of all the main themes in Western philosophy in general.

In this method, a series of questions are posed to help a person or group to determine their underlying beliefs and the extent of their knowledge. The Socratic method is a negative method of hypothesis elimination, in that better hypotheses are found by steadily identifying and eliminating those which lead to contradictions. It was designed to force one to examine his own beliefs and the validity of such beliefs.

Noteworthy Quote (recorded by Plato in The Apology):

The unexamined life is not worth living for a human being.

May 21, 427 B.C.E.

Today is thought to be the date of birth of the Greek philosopher Plato, student of Socrates and teacher of Aristotle. Together the three formed the basis of Western philosophy. Nevertheless, when one compares Plato with some of the other philosophers who are often ranked with him — Aristotle, Aquinas, and Kant, for example — he can be recognized to be far more exploratory, incompletely systematic, elusive, and playful than they. That, along with his gifts as a writer and as a creator of vivid character and dramatic setting, is one of the reasons why he is often thought to be the ideal author from whom one should receive one’s introduction to philosophy.

Plato founded the Academy in Athens, Greece, which is considered to have been the prototype of the modern university. Many of his writings focused on justice, virtue and politics, although he also had great interest in rhetoric, art, and literature. Plato himself did not contribute substantial works directly to science and mathematics, but his stress on mathematics and philosophy, and his insistence on defining terms rather than trusting intuition, influenced many later thinkers. Furthermore, his ideas on education and what constituted knowledge inspired his followers to explore the world in new ways.

In Plato’s dialogue entitled Theaetetus, Socrates considers a number of definitions as to what knowledge is, the last being that knowledge is true belief that has been “given an account of” — meaning explained or supported in some way. According to this definition, in order to know that a given proposition is true, one must not only believe the relevant true proposition, but one must also have a good reason for doing so. In other words, no one would gain knowledge just by believing something that happened to be true. For example, an ill person with no medical training, but a generally optimistic attitude, might believe that he/she will recover from his/her illness quickly. Nevertheless, even if this belief turned out to be true, the patient would not have known that he/she would get well since his/her belief lacked justification. This is the most widely accepted definition of knowledge that has persisted to the modern day.

Noteworthy Quote:

Every heart sings a song, incomplete, until another heart whispers back. Those who wish to sing always find a song. At the touch of a lover, everyone becomes a poet.

May 20, 1747 (a Saturday)

James Lind wrote in his A Treatise of the Scurvy (published in 1753):

On the 20th of May, 1747, I took twelve patients in the scurvy on board the Salisbury at sea. Their cases were as similar as I could have them.

Thus began Lind’s description of his classic therapeutic experiment on sailors with the scurvy in which various, then proposed remedies, were tested as antiscorbutics. His report continued:

[The subjects] lay together in one place…in the fore-hold; and had one common diet, viz. water-gruel sweetened with sugar in the morning; fresh mutton-broth often times for dinner;…and for supper, barley and raisins, rice and currants, sago and wine, or the like. Two of these were ordered each a quart of cider a-day. Two others took twenty-five [drops] of elixir vitriol three times a-day, upon an empty stomach…Two others took two spoonfuls of vinegar three times a-day, upon an empty stomach;…Two of the worst patients…were put under a course of sea-water. Of this they drank half a pint every day…Two others had each two oranges and one lemon given them every day. These they eat with greediness, at different times, upon an empty stomach. They continued but six days under this course, having consumed the quantity that could be spared. The two remaining patients, took the bigness of a nutmeg three times a-day, of an electuary recommended by an hospital-surgeon, made of garlic, mustard-seed, [horse-radish], balsam of Peru, and gum myrrh…

The consequence was, that the most sudden and visible good effects were perceived from the use of the oranges and lemons; one of those who had taken them, being at the end of six days fit for duty… The other was the best recovered of any in his condition; and being now deemed pretty well, was appointed nurse to the rest of the sick.

Cider, Lind reported, had the next best effect. There was no remarkable alteration of the course of the disease in any of the other patients at the end of the two weeks’ tests. Although he does not mention them in the quotation above, Lind had a control group — all the other patients on board of his ship. These patients did not get anything that might cure their disease — all they got was a pain-killing paste (“lenitive electuary”), a laxative (cremor tartar), and/or a cough syrup (“pectoral”). It is clear that these products can have an effect on the symptoms (pain, constipation) but will not cure the disease. Thus, Lind’s experiment provided clear evidence of the curative value of oranges and lemons and was also the first example of a controlled clinical trial using human subjects.

Xenophanes of Colophon

Xenophanes was a native of Colophon in ancient Greece, born about 570 BCE. It is difficult to determine the dates of his life with any accuracy and the facts of his life are also obscure. However, it is known that he left Colophon after it fell to the Medes in 546/5. With the threat of the invasion of Ionia and mainland Greece by the Persians in the Persian War, he moved to Syracuse. Unlike the other Ionian philosophers, he wrote poetry rather than prose. Some believed that he taught Parmenides and founded the Eleatic school of philosophy; however, he is now considered to have been a relatively solitary thinker. He is also known to be the first person in recorded history to recognize the existence of fossils as hardened remains or traces of once-living organisms from some previous geological period, preserved in rock formations of Earth’s crust.

Although “fossil” is now a common and widely used word, whose meaning is known to practically everyone, the general acceptance of the idea that fossils are the remains of ancient organisms required millennia to achieve. One reason for this is that the great age of Earth also was not widely appreciated until relatively recently. Without an Earth eons old the idea of ancient life and the idea of fossils are meaningless.

Xenophanes described the occurrence of clam shells in rocks outcropping in mountainous parts of Attica. He recognized that these lithified clam shells were closely similar to clams that were then living along the coastline of the Aegean Sea. To account for the occurrence of these lithified clam shells far from the present sea, he argued that they were the preserved remains of clams that had lived at an earlier time when Attica was covered by an ocean. Hippolytus of Rome (c. 170 – c. 236) in his Refutation of all Heresies (1.14.5-6) records that Xenophanes studied the fossils to be found in quarries:

Xenophanes declared that the sea is salty because many mixtures flow together in it… He believes that earth is being mixed into the sea and over time it is being dissolved by the moisture, saying that he has the following kind of proofs, that sea shells are found in the middle of the earth and in mountains, and the impressions of a fish and seals have been found at Syracuse in the quarries, and the impression of a laurel leaf in the depth of the stone in Paros, and on Malta flat shapes of all marine life. He says that these things occurred when all things were covered with mud long ago and the impressions were dried in the mud.

However, in 750 BCE there were no quantitative methods for verifying this hypothesis, and so Xenophanes’ rather modern-sounding explanation for these clams could not be tested, and disappeared from view. The geological ideas of Xenophanes, then, must be listed among those remarkable Greek anticipations of nineteenth-century science which suffered almost total eclipse in the intervening centuries.

April 1, 1578

On this date, the English physician and scientist William Harvey was born. He is credited with being the first in the Western world to describe correctly and in exact detail the systemic circulation and properties of blood being pumped around the body by the heart. Harvey published his discovery in a treatise entitled Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (On the Motion of the Heart and Blood in Animals) in 1628. His discovery was dramatically confirmed later in the seventeenth century by microscopist Marcello Malpighi’s discovery of capillaries.

Functional knowledge of the heart and the circulation had remained almost at a standstill ever since the time of the Greco-Roman physician Galen – 1,400 years earlier. With Harvey, life began to receive mechanistic explanation. The essential idea of mechanistic explanation is that “natural” events have “natural” causes and can be explained by cause-and-effect relationships that do not involve special action of supernatural agency. This is fundamental to modern science.

In Exercitationes de Generatione Animalium (On the Generation of Animals) in 1651, Harvey was extremely skeptical of spontaneous generation and proposed that every living animal originally comes from an egg, introducing the oft-quoted phrase “ex ova omnia” (all [life] from eggs). [However, Harvey did not completely reject spontaneous generation.] His experiments with chick embryos supported the theory of epigenesis, which states that organisms develop from substances in the egg that differentiate during embryonic development.  This was in conflict with the now-descredited preformationist view that perfect miniature versions of offspring exist in the gametes and grow during development.  [Please note that the term 'epigenesis' carries different meanings. Here, it used used in the older sense, as a theory of animal and plant development. In more modern times, it refers to mechanisms by which gene regulation over generations is controlled by elements other than DNA.]

March 31, 1596 (a Sunday)

On this date, the French mathematician, anatomist, physiologist, and philosopher René Descartes was born in La Haye in the region of Touraine, France. He is often regarded as the first modern thinker to provide a philosophical framework for the natural sciences as these began to develop. In his Discourse on the Method of Rightly Conducting One’s Reason and Of Seeking Truth in the Sciences (1637) he attempts to arrive at a fundamental set of principles that one can know as true without any doubt.

Figure 1 from Descartes’ De homine (1664), depicting the human heart.

Descartes is also known for the mind/body dualism he first articulated in his De homine (Treatise on Man), which he completed in Holland about 1633, on the eve of the condemnation of Galileo. When his friend and frequent correspondent, Marin Mersenne, wrote to him of Galileo’s fate at the hands of the Inquisition, Descartes became concerned for his own safety and refused to have De homine printed. Consequently, the first edition of this work was not published until 12 years after the author’s death.

According to Descartes’ principle of dualism, the body works like a machine, has the material properties of extension and motion, and follows the laws of physics. The mind (or soul), on the other hand, is described as a nonmaterial thinking entity that lacks extension and motion, and does not follow the laws of physics. Descartes argued that only humans have minds, and that the mind interacts with the body at the pineal gland. [He chose the pineal gland because it appeared to him to be the only organ in the brain that was not bilaterally duplicated and because he believed, erroneously, that it was uniquely human.] In De homine, he wrote:

I suppose the body to be nothing but a statue or machine made of earth, which God forms with the explicit intention of making it as much as possible like us…

William Harvey’s recent discovery that the heart acts as a pump to circulate the blood had supplied additional arguments in favor of Descartes’ mechanical theory – in fact, Descartes probably did much to popularize the discovery. The Cartesian dualism set the agenda for philosophical discussion of the mind/body problem for many years after Descartes’ death.

February 19, 1626 (a Thursday)

On this date, the Italian physician and poet Francesco Redi was born.

Spontaneous generation (abiogenesis), a long-held theory that life springs up from non-living or decaying organic matter, was based on observations of rotting food seemingly producing living organisms. Francesco Redi, a respected philosopher at the court of the Medici Grand Duke in Tuscany, was the first scientist to question the idea of spontaneous generation. By setting up a simple experiment in which decaying meat was placed in three jars, one uncovered, one sealed, and one covered by mesh, allowing air to circulate, he demonstrated that only the open jar which flies could access produced maggots. Thus, decaying meat does not spontaneously produce maggots. Partially due to the simplicity of Redi’s experiment (anyone could reproduce it), people began to doubt spontaneous generation.

It is important to note that what Redi and others demonstrated is that life does not currently spontaneously arise in complex form from nonlife in nature; they did not demonstrate the impossibility of life arising in simple form from nonlife by way of a long and propitious series of chemical steps/selections under conditions that do not exist on Earth today. In particular, they did not show that life cannot arise once, and then evolve. Neither Pasteur, who put to rest the notion of spontaneous generation for microorganisms, nor any other post-Darwin researcher in this field denied the age of planet Earth or the fact of evolution.

January 22, 1561

On this date, the English philosopher Francis Bacon was born. His book, Advancement of Learning (1605), was partially responsible for the founding of the Royal Society of London.

January 20, 1692, O.S. (a Wednesday)

On this date [the year to Salemites was 1691, since the new year began on March 25 in those days] in Salem Village in the Massachusetts Bay Colony (present-day Danvers, Massachusetts), Abigail Williams, age 11, and Elizabeth Parris, age 9, began having “fits” involving behavior such as blasphemous screaming, convulsive seizures, trance-like states, and mysterious spells. Soon Ann Putnam, Jr., age 11, Mercy Lewis, age 17, Mary Walcott, also age 17, and other Salem girls began acting similarly.

So began one of the most famous travesties of justice in history – the Salem Witchcraft Trials. The proceedings were notable for their lack of empirical reason, skepticism, and humanitarianism; they were instead based on supersitition, ignorance, fear, and intolerance.

The Witch House, the home of Magistrate Jonathan Corwin in 1692.

In mid-February, unable to determine any physical cause for the symptoms and dreadful behavior, the physician William Griggs concluded that the girls were under the influence of an “Evil Hand” – Satan. Under pressure from the Reverend Samuel Parris and magistrates Jonathan Corwin and John Hathorne to identify the source of their affliction, the girls named three women as witches: Tituba, the Parris’ Caribbean slave; Sarah Good, a homeless beggar; and Sarah Osborne, an elderly impoverished woman. On February 29, warrants were issued for their arrests.

Over the following weeks, other townspeople came forward and testified that they, too, had been harmed by or had seen strange apparitions of some of the community members. By the end of the witch hunt, more than 200 people had been accused of practicing witchcraft – the “Devil’s magic.”

To try the witchcraft cases, Governor William Phips on May 27, 1692 ordered the establishment of a Special Court of Oyer (to hear) and Terminer (to decide) for Suffolk, Essex, and Middlesex counties. The seven magistrates of this court based their judgments and evaluations on various kinds of intangible evidence, including direct confessions (some the result of torture), supernatural attributes (such as “witchmarks”), and especially the reactions of the “afflicted” girls. The latter involved spectral evidence, the appearance of the accused’s apparition or “specter” to an “afflicted” girl, and the test of touch, the sudden cessation of her fit after being touched by the accused witch. Spectral evidence was based on the assumption that a witch could send out his/her specter, an incorporeal being indistinguishable to those who could see them from the witch himself/herself. The specter had human powers of sight, hearing, speech, and touch and superhuman ones of locomotion, so it could torment and afflict the “saints” to lead them astray. The touch test was based on the assumption that the girl was made well by physical contact with the witch because it allowed the witch’s evil to flow back from the “afflicted” girl.

English courts, while recognizing the credibility of “spectral evidence,” refused to prosecute alleged capital offenses on the basis of “spectral evidence” alone. That was not the case in New England. During the witch trials the “afflicted” girls claimed that various people of Salem Town and Salem Village had appeared to them to lead them into witchcraft and to cast spells upon them. Furthermore, the girls claimed to see “specters” even in the courtroom. The magistrates accepted such evidence as credible and admissible for judgment and sentencing. Thomas Brattle described the court procedure in a letter he wrote (see below) to the General Court of Massachusetts in October:

First, as to the method which the Salem Justices do take in their examinations, it is truly this: A warrant being issued out to apprehend the persons that are charged and complained of by the afflicted children, (as they are called); said persons are brought before the Justices, (the afflicted being present.) The Justices ask the apprehended why they afflict those poor children; to which the apprehended answer, they do not afflict them. The Justices order the apprehended to look upon the said children, which accordingly they do; and at the time of that look, (I dare not say by that look, as the Salem Gentlemen do) the afflicted are cast into a fitt. The apprehended are then blinded, and ordered to touch the afflicted; and at that touch, tho’ not by the touch, (as above) the afflicted ordinarily do come out of their fitts. The afflicted persons then declare and affirm, that the apprehended have afflicted them; upon which the apprehended persons, tho’ of never so good repute, are forthwith committed to prison, on suspicion for witchcraft….

The first case brought to the special court was Bridget Bishop, an older woman known for her gossipy habits and promiscuity. She was tried on June 2 and, on June 10, became the first person hanged on what eventually became known as Gallows Hill. Troubled by this event, Governor Phips consulted the ministers of Boston, including Increase Mather and his son, Cotton. They wrote the Return of the Ministers Consulted, in which they advised caution in the witchcraft proceedings but concluded:

Nevertheless, we cannot but humbly recommend unto the Government the speedy and vigorous prosecution of such as have rendered themselves obnoxious, according to the direction given in the laws of God, and the wholesome statutes of the English nation, for the detection of witchcrafts.

Five people were sentenced and hanged in July, five more in August and eight in September. One accused witch (or wizard, as male witches were often called) was pressed to death on September 19 because he refused to enter a plea to the charges of witchcraft against him. On October 3, after 20 people had been executed in the Salem witch hunt, the Reverend Increase Mather, who was the father of Cotton Mather and then president of Harvard College, delivered a sermon entitled Cases of Conscience concerning Evil Spirits Personating Men, in which he denounced the use of spectral evidence – the girls’ visions – and said:

It were better that ten suspected witches should escape than one innocent person be condemned.

On October 8, 1692, Thomas Brattle, a merchant, mathematician, astronomer, and Fellow of the Royal Society, wrote an eloquent letter (quoted above) criticizing the witchcraft trials and convictions to the members of the General Court. This letter and Increase Mather’s Cases of Conscience apparently had great impact on Governor Phips, who on October 12 prohibited further imprisonments for witchcraft. On October 26, the General Court dismissed the Court of Oyer and Terminer, and on October 29, the Governor formally dissolved it. On November 25, 1692, the General Court created the Superior Court of Judicature to try the remaining witchcraft cases, but spectral evidence was now disallowed. This time, only 3 of 56 defendants were condemned, and Phipps pardoned them along with five others awaiting execution. In May 1693 Phips pardoned all those who were still in prison on witchcraft charges. They were free – provided they could pay their jail bills.

On August 25, 1706, Ann Putnam, Jr. publicly apologized in Salem Village Church for causing the deaths of innocent people and said it was due to a “great delusion of Satan.” Eventually, the colony admitted the trials were a mistake and compensated the families of those convicted. However, Massachusetts did not formally apologize for the events of 1692 until 1957 – more than 250 years later.

The tragic events in Salem Village in 1692 clearly illustrate why alleged supernatural entities or forces are no longer admissible in legal proceedings as evidence of the guilt or innocence of the accused. The Enlightenment, beginning in the late 1680s, contributed to the end of witchhunts throughout Europe and America by pointing out that there was no empirical evidence that alleged witches caused real harm and by emphasizing that the use of torture to force confessions was inhumane. The Enlightenment also resulted in replacing superstition with science, which does not use supernatural entities or forces to explain natural phenomena – such as the bizarre behavoir of Abigail Williams and Elizabeth Parris.

References:

• Frances Hill, A Delusion of Satan: The Full Story of the Salem Witch Trials (Cambridge, MA: Da Capo Press, 1995).
• Marilynne K. Roach, The Salem Witch Trials: A Day-by-day Chronicle Of A Community under Siege (New York, NY: Cooper Square Press, 2004).
• Carl Sagan, Demon Haunted World: Science as a Candle in the Dark (New York, NY: Random House, 1995) 401-420.

December 31, 1514, O.S. (a Sunday)

On this date at 5:45 AM, the physician and anatomist Andreas Vesalius was born in Brussels, Belgium (at that time part of the Holy Roman Empire). Vesalius sought to understand the mechanisms of the natural world through careful observation, no longer relying on texts by ancient authorities. He is often referred to as the founder of modern human anatomy.

Vesalius studied in Louvain and Paris before earning a doctorate in medicine at the University of Padua in 1537. Appointed there as a lecturer in surgery at the age of twenty-three, he quickly consolidated his reputation as both a teacher and an anatomist. Perhaps his most famous accomplishment was the publication in 1543 of De humani corporis fabrica libri septem (Seven Books on the Construction of the Human Body), or the Fabrica, a text that contained the first accurate illustrations of internal human anatomy. His book overthrew many of the previously uncontested doctrines of the second-century anatomist Galen, and caused a storm of criticism from other anatomists. It was revolutionary, as he was among the first to perform thorough cadaver dissections himself. He showed that Galen’s anatomy was merely an attempt to apply animal structure to the human body, and was not based on any direct knowledge of human anatomy. In the preface of Fabrica, dated August 1, 1542, Vesalius wrote:

To this man they have all so entrusted their faith that no doctor has been found who believes he has ever discovered even the slightest error in all the anatomical volumes of Galen, much less that such a discovery is possible: even though (notwithstanding that Galen often corrects himself, that more than once after learning better he points out in some books a careless error he has made in others, and that he often contradicts himself) – even though it is just now known to us from the reborn art of dissection, from the careful reading of Galen’s books, and from the welcome restoration of many portions thereof, that he himself never dissected a human body, but in fact was deceived by his monkeys (granted a couple of dried-up human cadavers came his way) and often wrongly disputed ancient doctors who had trained themselves in human dissections. In fact, you will find many things in Galen which he misunderstood even in monkeys, not to mention the most astonishing fact that among the many and infinite differences between the organs of the human body and the monkey Galen noticed only those in the fingers and the flexion of the knee; he would no doubt have missed these as well, had they not been obvious to him without dissecting a human.

Vesalius’s discovery of the important differences between species also helped usher in the science of comparative anatomy, in which researchers studied animals to find their similarities and differences. In the process, they gradually began to recognize humans as being one species among many, with a few unique traits but many others shared in common with other animals. Some 300 years after Vesalius first shook off the blind obedience to Galen, Darwin used that vast stock of anatomical knowledge to build his theory of evolution.

December 27, 1822 (a Friday)

On this date, the chemist and microbiologist Louis Pasteur was born in Dole in the Jura region of France.

From the time of the ancient Romans, through the Middle Ages, and until the late nineteenth century, it was generally accepted that some life forms arose spontaneously from nonliving matter. Such “spontaneous generation” appeared to occur primarily in decaying matter. For example, a seventeenth century recipe for the spontaneous production of mice required placing sweaty underwear and husks of wheat in an open-mouthed jar, then waiting for about 21 days, during which time it was alleged that the sweat from the underwear would penetrate the husks of wheat, changing them into mice. Likewise, the spontaneous generation hypothesis was proposed by scientists to explain the origin of the “animalcules” observed by Antoni van Leeuwenhoek in his magnifying lenses and had received wide acceptance all over Europe. Although such a concept may seem laughable today, it was consistent with the other widely held cultural and religious beliefs of the time.

It wasn’t until Louis Pasteur that this fallacy was finally disproved. In 1859, the French Academy of Science offered the Alhumbert Prize of 2500 francs to whoever could shed “new light on the question of so-called spontaneous generation”. Young Pasteur’s award winning experiment was a clever variation of earlier experiments performed by John Needham (1713-1781) and Lazzaro Spallanzani (1729-1799). Pasteur filled a long necked flask with meat broth. He then heated the glass neck and bent it into an “S” shape. Air could reach the broth, but gravity acted to trap airborne microorganisms in the curve of the neck. He then boiled the broth. After a time, no microorganisms had formed in the broth. When the flask was tipped so that the broth reached the microorganisms trapped in the neck, the broth quickly became cloudy with microscopic life.

Thus, Pasteur disproved spontaneous generation. Furthermore, Pasteur proved that some microorganisms are airborne. “There is no known circumstance in which it can be confirmed that microscopic beings came into the world without germs, without parents similar to themselves,” he concluded in 1864. His experiment also supported germ theory. Germ theory states that specific microscopic organisms are the cause of specific diseases. While Pasteur was not the first to propose germ theory (Girolamo Fracastoro, Agostino Bassi, Friedrich Henle and others had suggested it earlier), he developed it and conducted other experiments that clearly indicated its correctness, thereby managing to convince most of Europe it was true.

Despite what creationists and proponents of “intelligent design” may insist, Pasteur’s research on spontaneous generation did not demonstrate the impossibility of life arising in simple form from nonliving matter under conditions vastly different from those today and by means of a long and propitious series of chemical steps/selections. In particular, he did not show that life cannot arise once, and then evolve. Neither Pasteur, nor any other post-Darwin researcher in this field, denied the age of Earth or the fact of evolution. What Louis Pasteur and the others who denied spontaneous generation did demonstrate is that life does not currently spontaneously (i.e., within a matter of weeks) arise in complex form from nonlife in nature.

December 18, 1912 (a Wednesday)

Working at Piltdown.

 

 

On this date, the discovery of the skull known as Piltdown man, the first important fossil human skull ever to be unearthed in England, was announced at a meeting of the Geological Society of Great Britain. Charles Dawson, steward of Barkham Manor, an attorney, and secretary to the Sussex Archaeological Society, and Arthur Smith Woodward, keeper of geology at the British Museum, announced their remarkable find had been made at Piltdown Common. The specimen, known as Piltdown man, occupied an honored place in the catalogues of fossil hominids for the next 40 years. But in 1953, thanks to some rigorous scholarly detective work, Piltdown man was revealed to be nothing more than a forgery, manufactured from modern human and animal remains.

A Tale of Two Hypotheses

The cause of the rapid evolutionary growth in hominid brain size remains a mystery and a major point of contention among anthropologists. (Hominids are humans and human-like primates). Our brains weigh roughly twice as much as those of our similarly-sized earliest human relative, Homo habilis, which lived two million years ago. Also, humans have extraordinarily large and complex brains compared with non-human modern primates. The human brain is several times larger than that of the macaque monkey – even after correcting for body size – and it is far more complicated in terms of structure. Although humans weigh about 20 percent more than chimpanzees, our closest living relative, the human brain weighs 250 percent more. And keep in mind that a huge brain is a serious investment – neural tissue guzzles a lot of energy.

Two main hypotheses have been proposed to explain why humans have evolved larger brains than their primate relatives:

• The general intelligence hypothesis suggests that bigger brains make humans better and faster at all kinds of cognitive skills, such as memorizing, learning, and planning ahead. In other words, humans differ from apes uniformly across physical and social cognitive tasks because they have greater general intelligence. Physical skills involve understanding concepts of space, quantities, and causality. Social skills involve understanding nonverbal communications, imitating another’s solution to a problem, and understanding that other individuals have their own beliefs and intentions. For example, biting and trying to break a plastic tube to retrieve the food inside demonstrates a physical skill, while following another’s example to pop open the tube to retrieve the food demonstrates a social skill.
• The cultural (or social) intelligence hypothesis says that bigger brains have enabled humans to develop, in particular, more complex social cognitive skills to interact in cultural groups.

One way to distinguish between these two hypotheses is to compare the cognitive abilities and skills of humans with other non-human primates. If the general intelligence hypothesis is true, then we expect to see a difference between humans and apes in both physical and social skills. If the cultural intelligence hypothesis is true, then we expect to see a difference primarily in social skills.

This experiment is exactly what was performed by Esther Herrmann and her colleagues of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and recently reported in the September 7 issue of the journal Science. They put 105 young German children (Homo sapiens), 106 chimpanzees (Pan troglodytes), and 32 of the more evolutionarily distant orangutans (Pongo pygmaeus) through a series of complex tests. The children were all about 2.5 years old, an age when they have about the same physical skill level of chimpanzees, and had been speaking for at least a year. The apes ranged in age from 3 to 21 and had all been made accustomed to humans. The researchers designed 16 different puzzles to tease out the differences in ability between humans and apes. The tests took between three and five hours and were spread between five and eight days over two weeks. The apes were tested in the sanctuaries where they live in Africa and Indonesia.

The results found that chimpanzees, human children, and orangutans were all equally successful in the physical skills tests. But the human children were significantly better at the social skills tests – scoring around 74 percent correct on the tests compared to scores of 33 percent from both groups of apes.

The findings support the cultural intelligence hypothesis but contradict the general intelligence hypothesis. Joan Silk, an anthropologist at the University of California, Los Angeles, who was not involved in the study, observed that “compared [with] baboons we waste an awful lot of time gossiping about one another.” Aside from gossiping, these increased social skills appear to carry strong evolutionary advantages, enabling humans to sustain relationships with others and help each other out in times of need. A growing body of evidence suggests that the quality of social relationships has measurable fitness consequences for individuals. However, this may have come with some hidden costs. Silk commented that “the human brain is a really complicated machine that goes wrong with some frequency. Mental illness may be the evolutionary cost of this complexity.”

References:

• Herrmann, E., Call, J., Hernandez-Lloreda, M.V., Hare, B., Tomasello, M. (2007). Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis. Science, 317(5843), 1360-1366. DOI: 10.1126/science.1146282
• Silk, J.B. (2007). Social Components of Fitness in Primate Groups. Science, 317(5843), 1347-1351. DOI: 10.1126/science.1140734

Common Nonsense

I was doing some Internet surfing recently when I came upon a post entitled “Evolutionist Fundamentalism.” Normally, I ignore these rants, as they are usually written by people who are so sure they are correct that it is pointless to try to reason with them. (Of course, I am also convinced I am correct, but I have logic and, more importantly, empirical evidence on my side. But more on this later.) However, this time the misconceptions were ones I am sure are on the minds of many non-scientists and are therefore worth addressing.

The post was written by a woman named Nonni. She begins:

I went back to college as an “older woman”. I started taking biology courses, thinking I would like to be a health educator or writer. I immediately ran up against what I saw as absolute dogma regarding the theory of evolution. As a much younger person I had learned evolution was one theory to explain the origin of biological complexity. However when I learned a single cell has over 300 different chemical reactions needed for its metabolism, not to mention its reproduction, I thought to myself–”what a marvelous design”. Design made sense.

This is like waving a red flag in front of a bull. First of all, nothing in science is “received doctrine” or “absolute dogma.” Anyone the least bit familiar with the history of science will realize that scientists can make conclusions only by using the best empirical (meaning observable and/or measurable) evidence available to them – and as new observations are made and new experiments done, it often becomes necessary to revisit previous conclusions and change them. It may take awhile, but nevertheless, it happens. (Furthermore, scientific knowledge is determined by consensus and informally within the scientific community. There is no referendum, plebiscite, or authority that rules on the veracity of a scientific claim.)

As a result, we say that scientific knowledge is “provisional.” Of course, then opponents go to the opposite extreme and say that since nothing in science is certain, scientific knowledge must be “worthless.” Let me point out that, philosophically speaking, nothing in life is certain. (And if you think otherwise, you are fooling yourself.) For example, the verdict of a jury in a criminal trial about a defendant’s guilt is provisional in the same way that a conclusion in science about the truth of a claim is provisional. In both cases, the standard of justification is “empirical evidence that convinces beyond a reasonable doubt.” Just as with conclusions in science, verdicts of juries sometimes have to be revisited when new evidence comes to light, sometimes years later. An example of this occurred recently when the murder conviction of a 56-year-old man was overturned and he was freed after spending 25 years in prison. Willie Earl Green was convicted in the 1983 execution-style murder of a 25-year-old single mother in South Los Angeles. A judge ordered him released last Thursday, March 20, because the witness whose trial testimony had sent Green away for 33 years to life had recanted, and prosecutors decided not to retry Green. The witness, Willie Finley, explained that he was high on cocaine during the killing and had been “helped” by police to identify Green as a suspect. Likewise, the development of “DNA fingerprinting” has made possible the release of many innocent men who were falsely convicted of rape years ago, before this technology was available. Conclusions have to be made, and can only be made, by using the best evidence available at the time.

Back to Nonni. She continues:

There has been quite a lot of writing lately about evolution, and the possibility of intelligent design co-existing with it. Intelligent design answers questions regarding the unlikelihood that random selection could ever result in the vast complexity we see in biology. For the average person, it meets the standard of common sense. This is not creation science, biblical faith, or anything similar. However Intelligent Design theory is too uncomfortable for the belief system of the majority of evolutionists. Evolutionists resemble fundamentalists, in several ways.

So she says. First of all, the “random selection” she slips in introduces a “straw-man” argument. Natural selection is not “random selection,” but by saying it is, creationists can appeal to the “common sense” of the “average person” to make natural selection seem illogical. Instead, this line of reasoning illustrates the fact that Nonni really didn’t learn anything about evolution in her biology classes. Natural selection is the result of two things: individual variation and competition among members of a population. Individual variation is the result, ultimately, of mutation – and mutation is a random process. However, excess reproduction and limited environmental resources make competition among members of a population inevitable, and only those individuals with advantageous heritable traits (called adaptations) are likely to survive and produce healthy offspring. This is natural selection. Since more and more offspring inherit these advantageous heritable traits in each generation, these traits become more common – but there is nothing random about selection. Only certain, specific traits are preserved because, in the given environment, individuals with them have greater reproductive success.

Secondly, things happen in nature the way they do – whether or not they agree with our notion of “common sense.” For example, does Nonni know about quantum mechanics? It is a set of rules, the most successful of any in the history of science, that describes things that happen at the level of atoms and particles such as electrons, protons, and neutrons. Do a certain experiment with electrons and they behave like particles, but do a different experiment and they behave like waves. In the macroscopic world we live in, we know of nothing that behaves this way – in fact, we can’t even imagine something that behaves this way. The most unnerving idea in quantum mechanics may be the notion that certain particles can affect one another almost instantly across vast reaches of space. In 1935, Albert Einstein pointed out that synchronized atoms – “spooky action at a distance,” as he called it – are not only permitted by quantum mechanics but are an example of its absurdity. “No reasonable definition of reality could be expected to permit this,” he, Boris Podolsky and Nathan Rosen confidently wrote in a paper in 1935. However, far from demolishing quantum theory, that paper wound up as the cornerstone for the new field of quantum information – in fact, it is the most cited of Einstein’s papers. Long after Einstein’s death, experiments were finally performed in 1982 by Alain Aspect and his colleagues at the University of Orsay in France, the results of which confirmed quantum mechanics and not reality as Einstein had always presumed it should be. Paradoxically, Einstein had once written to a friend, “The more success the quantum theory has, the sillier it seems.”

Next, Nonni writes:

1. Scientific authority is deemed absolute in that the scientific community has determined what is and what is not to be included in the realm of scientific inquiry. If something is deemed to be outside the realm of scientific inquiry, it is to be denied existence entirely. Evolutionists will never say that the theory of Evolution also falls outside the realm of scientific inquiry. As an explanation for the origin of all biological forms, it technically does. The origin of all biological life simply cannot be observed, measured or reproduced. Intelligent Design, however, has been deemed to be outside the realm of scientific inquiry, although as a theory, it fits the facts of complexity better than random selection, which has mathematically impossible odds.

So many misconceptions, so little space. First, Nonni repeats her argument of natural selection as “random,” which, as I have pointed out, is a non-starter.

Secondly, Darwin’s theory of evolution, and the modern synthetic theory of evolution, have nothing to do with the origin of life on Earth. The theory does not deal with how life came to be on this planet – it only deals with how living things have changed over time since their first appearance. The evolution of living things has been observed, measured, and reproduced. Even if human beings were not present to see some of these events happen before their very eyes, I would point out that many things are accepted as true even when there are no eyewitnesses. Defendants have been convicted of murder (and executed) even when there were no eyewitnesses, as long as there was circumstantial evidence that convinced a jury of their guilt beyond a reasonable doubt. On the other hand, if I really didn’t want to believe that, say, George Washington ever existed, I would only have to argue that all the evidence – documents and artifacts alike – could have been forged and concocted by conspirators to make it look like he was a real person. But then, that would be “unreasonable doubt.”

Thirdly, the origin of “all biological life” can be investigated by science because hypotheses can be proposed that can be tested. Scientists can do experiments in the lab that simulate conditions as they may have existed on Earth some four billion years ago. These experiments confirm that life could have chemically evolved from inanimate matter under those conditions without the aid of any “intelligence.” There is no hypothesis that Intelligent Design can propose that can be tested because advocates have no idea (at least, when they are not at Church) who or what this Intelligence might be. This Intelligence, unless it can be empirically verified, is as good an explanation for the origin of “all biological life” as is Santa Claus. [However, this is not the same thing as claiming that an Intelligence (or Santa Claus) does not exist.] In short, an explanation must be testable to be scientific.

Now, Nonni gets nasty:

2. Scientists are the new prophets. They hold the keys of knowledge to which the rest of the world has limited access. One simply can’t argue with a scientist since everyone who is not a scientist is discounted as inferior and ignorant.

Somehow, here I think the pot is calling the kettle black. First, science is not a body of knowledge that has been revealed only to the “chosen” or the “elect” few. It is a basic assumption of science that anyone, in principle, can repeat observations and experiments to confirm the facts of science. Secondly, for someone who claims not to be able to “argue with a scientist,” she seems to be doing quite well. And I don’t think it is fair to say that all scientists consider anyone who argues with them to be “inferior and ignorant” – anymore than it is fair to say that all creationists who argue with scientists consider them to be “inferior and ignorant.” Although, on the issue of science and evolution, I think Nonni is misinformed and has much to learn.

But Nonni has more to say:

3. Evolutionary theory is now taught everywhere as fact, when it is in reality unproven theory. Since it is the only theory allowed under the criteria of scientific inquiry, it is the only theory available, and therefore is a fact.

Boy. I wish evolutionary theory was now taught everywhere as fact. It often is not taught at all in the public schools.

First, evolution is one of the most well-supported theories in science today. Her statement, again, illustrates her lack of knowledge about evolutionary biology. Maybe she is thinking of the “evolution is only a theory” canard promoted by creationists. In everyday usage, “theory” is often used in the sense of a guess or speculation. A hypothesis is an educated guess, but a theory is the goal of science – a set of related hypotheses about some natural phenomenon that has been tested repeatedly and extensively without being disproved. A theory is as close to the truth as science can get.

Secondly, the theory of evolution is not the only possible scientific explanation for the change we see in living things. However, the theory of evolution is the best explanation because the evidence overwhelmingly supports it better than any other. Creationists like to think that there are only two possible explanations for the diversity of the biological world, Intelligent Design or the theory of evolution, because then they mistakenly think it is an either/or situation. If they can show that evolution is false, they illogically think that that proves Intelligent Design is true. [In any case, Intelligent Design isn't a scientific explanation since it can't be tested.]

But there’s more from Nonni:

4. Where the theory of Evolution has gaps, inconsistencies or defies the knowledge of another discipline (i.e., mathematics), the truth of the theory must be taken on faith.

5. Universities are the new churches of Evolution. No one is admitted to the priesthood (faculty) unless they subscribe to the statement of faith. Evolution by random selection is an article of faith.

Now Nonni is really getting off the wall. I have heard this criticism from students. Evolution has “gaps.” Well, scientific knowledge has “gaps.” If this were not so, then there would be nothing left for scientists to investigate. We do research because there ARE things left to learn. But none of the so-called gaps in our knowledge of evolutionary biology in any way threatens or undermines the theory of evolution. Once again, Nonni refers to natural selection as “random selection,” preferring to defy the knowledge of biology. Finally, scientists do not rely on “faith” in evaluating the truth of a hypothesis or theory, because they don’t have to – they look at the empirical evidence. Her statement that “universities are the new churches of Evolution” is strident hyperbole, not worth responding to.

6. Whomever questions the doctrine of Evolution is an ignorant outsider, certainly unworthy of a teaching position, and probably also unworthy of a biological science degree.

This is how I see it. I went back to college as an “older woman”. Its very difficult for older people to go back to college. We have to overcome the common sense we’ve acquired through years of experience in living. But thats the subject of a whole new post–or maybe more.

Here, I detect a bit of sour grapes.

In conclusion, if you want to study science, or just become an educated person, you have to learn to critically evaluate what you think as rigorously as you critically evaluate what others think. This is how I see it.

References:

• A. Einstein, B. Podolsky, and N. Rosen, “Can quantum-mechanical description of physical reality be considered complete?” Physical Review 41: 777 (15 May 1935).
• A. Aspect, Dalibard, and G. Roger, “Experimental test of Bell’s inequalities using time-varying analyzers,” Physical Review Letters 49(25): 1804 (20 Dec 1982).

The Deceitful Jonathan Wells

Peppered moths are a classic evolutionary example of how a previously unknown trait can appear in a population and then come to dominate it due to a particular environmental change. That, of course, has also made them a major target for creationists, and Discovery Institute fellow Dr. Jonathan Wells has spent much of his career in trying to discredit the example, most famously by trying to claim that a posed example picture used in introductory textbooks somehow invalidated the detailed statistical results they were used to illustrate. Today, Mike Dunford does a fantastic job explaining exactly how Wells is still grossly misrepresenting both the original classic study as well as a recent definitive re-testing of the key predation results.

Biston betularia: There are two moths in this picture.