There is a tendency for members of Western Societies to consider science as an accomplishment – a set of settled, known facts and values. Accompanying this attitude is one which considers Scientists (with a capital "S") to be authoritative and wise, knowledgeable in many things other than their specialty. It is a stereotype established by some of the notable scientific figures (and communicators) of the past and present: Einstein, Sagan, Hawking... and perpetuated by a media which treats the notion of scientific expertise as knowledge itself. The very presence of three little letters after a name –- P-h-D – is taken by many to be a mark of authority, and the "Scientist" is accorded credibility and wisdom well beyond their due.
This is curiously at odds with a society that simultaneously praises and distrusts science. We live in an age filled with the wonders of scientific advancement –- from medical/health care, to computers, to self-driving cars –- yet we also have groups that loudly proclaim their distrust of anything "technological" or "scientific" and turn toward mystical and superstitious explanations instead. But this is not intended as a political rant, and I am not necessarily referring to the groups and actions that you might infer from the title or previous statements. Read on, and let's look at what science is, who scientists are, and examine the ways in which Science, as a field, makes mistakes, changes its mind, and arrives at its findings. We will then compare and contrast those observations with the quasi-religious approach which declares that the scientific evidence for or against a particular subject is "settled", that there is "consensus" among all right-thinking scientists who support that view, and that the opposition are "not real scientists" at all.
The Scientific Method
One of the most important considerations in judging the pronouncements and proclamations of "Science" is to understand that science is a process of examination and exploration, not a "fact", pronouncement, or conclusion. In essence, science consists of formulating a hypothesis from observed facts, creating experiments to prove or disprove the hypothesis, observing the results of the experiments, then making a conclusion to accept or reject the original hypothesis on the basis of those observations. This is commonly known as The Scientific Method and derives from Aristotle's original definitions of deductive reasoning.
"Science is a process, not a conclusion" -– you'll read that quite often in this article and in my other writing. I think that the exact wording is original to me, but it may have already escaped my control and entered the 'net at large, given that I use it quite often. I have a small plaque in my academic office which states: "Research is the process of going up alleys to see if they are blind." [I may have to use that in a title someday.] My graduate research mentor claimed that the plaque should read "Science is the process of going blindly to see if there are alleys."
But what does that say about the both scientific observation and conclusion? Certainly while one is *in* the alley, one can see *only* the alley, and it would be easy to conclude that the alley is in fact open, and not blind – until one reaches that blind end. Yet the true methodology of science is not about going blindly at all. If you Google "Scientific Method" – you find a definition that states that first, one formulates a question, i.e. what do you want to study? Then initial observations are made from an uncontrolled, natural context or environment. From those observations, a hypothesis is formed and experiments are proposed which will test – under controlled conditions – whether that hypothesis is true or false. What is meant by controlled conditions? Basically, the experimenter must ensure that there are no external factors which could produce a result without the experimenter's knowledge (I'll give a specific example in the next paragraph). The experiment is conducted, the observations made (and statistically analyzed if necessary (and more on that much later), and a conclusion made about the validity of the hypothesis. Good scientists stick to making claims only about their hypothesis. Very good scientists use their old hypothesis to form new ones to further refine and test their conclusions.
Here's an example. Like many academics, I can't get seriously started on my morning work without a cup of coffee. I like hazelnut-flavored powdered creamer, and I have a one-cup-at-a-time coffee brewer. If I choose the wrong setting, the cup gets full, and I risk spilling coffee as I stir in the creamer. Or I could put the creamer in the mug before the coffee, but I still have to stir it. So is the spillage from the stirring, or does the creamer make the mug too full -– after all, it's a powder and it dissolves. It shouldn't take up too much space, right?
So there's my question: I want to know if the spilled coffee is due to adding the powdered creamer (and not simply splashing the coffee as I stir it). Let's work through the steps of the scientific method:
- Question –- does adding powder to a liquid increase the volume of the liquid?
- Initial observations –- adding a powder that has to be stirred does indeed cause my coffee mug to overflow, but maybe it's because I have to stir it too much. There are two possible solutions to this:
- The powder adds volume to the liquid, and it overflows because of added volume –- we can test this because the interaction of liquid and solid is consistent under controlled circumstances.
- The powder adds no volume, thus it must be my stirring that causes the overflow –- we really can't test this, since my stirring technique changes each time.
- Hypothesis (aka The Null Hypothesis, H0) –- powder dissolved in a liquid does not add any volume.
- Thus, we choose to test (and negate) my first possible solution.
- Note that this Null Hypothesis also implies an Alternate Hypothesis, HA, which states: Powder dissolved in a liquid does add volume to the liquid.
- Put a measured amount of (liquid) coffee in a narrow, tall beaker with fine volume measurements engraved on the side. This is commonly known in the lab as a graduated cylinder.
- Allow the liquid to settle, and then measure the exact volume of the coffee.
- Measure a known weight (preferable to volume) of creamer to the liquid. Use tall enough beaker/cylinder and a means of stirring that will not allow any coffee to splash out.
- Stop stirring, allow the surface of the coffee to settle, and then measure the volume.
- Repeat several times and compare the measurements.
- Controls -- it is very important to perform your experiments under conditions such that there is no other cause of a change in the volume of the coffee.
- Since we know that heat causes liquids (water) to expand, and cold causes it to contract (until it ices and expands again) –- ensure that all tests are conducted using a thermometer to ensure the exact same temperature of coffee.
- Some powders are more dense (more weight per volume) than others, so always use the same type and brand of creamer, the same coffee, coffee maker, water, etc.
- Always allow the liquid to stop moving (from stirring and pouring) before measurement, and minimize the pouring or transfer of ingredients to avoid accidental spills.
- Analyze the data -- in our experiment, you will find that the creamer does indeed increase the volume of the coffee, but it may not be exactly the same each time because of factors outside of our control, such as variations in the packing density of the powdered creamer or small measurement errors. This is where statistics come in. Multiple repetitions of the experiment mean that we can calculate the average result (the Mean) and how much it randomly varies from trial-to-trial (the Variability). Variability is typically calculated as Standard Deviation, and generally, an experiment-induced change in the mean that is three times the Standard Deviation is considered "highly significant"
- Evaluate the hypothesis -- we observed that creamer does indeed increase the volume of the coffee. Thus we reject the Null Hypothesis and instead accept the Alternative Hypothesis.
As good scientists, we can now entertain other questions, such as: Does temperature matter? What about sugar instead of creamer? Does the sequence (coffee first or creamer first) matter? What about different liquids? Unfortunately, our experiment does not enable us to answer those questions –- after all, we specifically set up the conditions so that those factors were controlled -- but it does provide us with the means to perform further experiments and find out new answers.
Please note that nowhere in this explanation did I mention "facts," "conclusions," "consensus," or "settled." That's because science describes the process of looking. If we find a blind alley, we know to go back and look in another place... but it we fail to find the blind wall at the end of the alley, do we really know that the alley is not blind? Or merely that we have not yet found the end? For that, let's look at some of Science's famous blind alleys.
Famous Scientific Blunders
The Science is Settled (Blunder #1) - The Sun revolves around the Earth
Okay, you should have seen this one coming; it's the favored example of those attacking nonscientists, religion, and the just plain ignorant. But looking at it from a scientist point of view: Question –- Why does the sun always rise in the East and set in the West? Observations: The sun, moon and stars always follow the same rotation around the Earth. Conclusion: The Earth is the center of the system of sun moon and stars. This Aristotelian or Ptolemaic view of the universe was settled science.
The conclusion is, in fact, scientifically sound for its day and age. While Aristotle is credited with the origins of the Scientific Method, he and the astronomer Ptolemy really didn't have a way to conduct controlled experiments on heliocentrism (Sun-centered) versus geocentrism (Earth-centered). However, what they knew was that they had no evidence that the Earth moved, and they certainly knew how to measure movement _– wind, birds, water, a rolling ball, stars in the night sky. In fact, Ptolemy was a skilled scientist: astronomer and geographer... for the second century A.D. He confirmed many of the measurements of Eratosthenes (third century B.C.) regarding the roundness and circumference of the Earth. He also refined the knowledge of optics in terms of reflection, refraction and much of our current knowledge of optical illusion. Yes, he got some measurements wrong, such as the exact circumference of the Earth, but he did not have all of the tools necessary for the experiments that would have disproved his Null Hypothesis.
It took Copernicus to put all of the additional scientific observation of more than thirteen centuries into a new theory of heliocentrism. If Ptolemy had had the vision (pun-intended) to look carefully at the apparent reversal in the orbit (aka "retrograde motion") of Mercury, Venus and Mars, he, too, might have substituted the Sun for the Earth as the center of his astronomic model. Indeed, while Geocentrism was compatible with (and eventually central to) the early Christian faith, the heliocentric model did gain religious acceptance, via Pope Clement VII. Copernicus himself held a doctorate in Canon Law (i.e. church law). Thanks to the wonderful research done by Baen authors Eric Flint and Andrew Dennis for 1634: The Galileo Affair, we also know that the popular view that Galileo's 17th century "apostasy" consisted of defying the Catholic Church over heliocentrism, was in fact over other violations of church doctrine, rather than heliocentrism, which had been gaining Church acceptance for more than a century.
It is also useful to note that in disrupting the settled science of geocentrism and replacing it with heliocentrism, Copernicus was also guilty of accepting a conclusion that would later be proven false. By the 18th – 19th Centuries, William Herschel and Friedrich Bessel were showing that the sun might be the center of the solar system, but not of the universe. With Edwin Hubble's astronomical observations of the 20th Century, we started to get a view of our galaxy – indeed of multiple galaxies, and the study continues to expand our scientific knowledge of the universe, including results from the orbital telescope which bears Hubble's name.
In astronomical physics, science is not a conclusion: not geocentrism or even really heliocentrism, but a process of investigation, observation, testing and refinement to this day. My favorite example of continued scientific investigation was performed on the Moon on August 2, 1971, when Astronaut Dave Scott (Apollo 15) dropped a hammer and a feather onto the moon's surface. After three and a half centuries, they continued Galileo's famous experiments in gravity to demonstrate that (in the absence of air resistance) weight and volume were irrelevant to gravitational attraction. Science is ongoing, and never satisfied.
The Science is Settled (Blunder #2) – The human body is regulated by four "humours" which control health, emotion and mental state
Back when I was a student, I attended two years of medical school. That has how it was done in those dark ages [grin!], either physicians needed a firm grounding in physiology and pharmacology, or physiologists/pharmacologists needed a firm grounding in human systems (i.e. medicine). In the course (again, pun-intended) of study, we learned much of the history of medicine and related fields. Dating back (again) to Aristotle, there was a theory of four humours or bodily fluids, which governed health and wellbeing of a person. If the blood, phlegm, black bile and yellow bile were in balance, a person was healthy, but diseases were thought to result from an imbalance of the biles. If a person was courageous and hopeful, but overly amorous, they had an abundance of blood; cowardice or failing libido was thought to reflect too little blood – strangely attributed to the liver, and not the heart. Yellow bile, from the gall bladder, was associated with anger and bad temper; black bile (from the spleen, with irritability, depression and sleeplessness. Phlegm, from the brain and/or lungs was associated with calm, but also lack of emotion. From these humours, we also got the names for temperaments: sanguine (blood), choleric (yellow bile), melancholic (black bile) and phlegmatic (phlegm).
Pretty archaic and backward, right? Modern science would never admit that this theory or its originator has a place in the practice of medicine – or would they? Except the historical personage associated with the theory was Hippocrates, known as the Father of Medicine, and for whom the Hippocratic Oath (medical ethics most famous guideline: "First do no harm") is named. The concept of humours likely originated in the 5th century B.C., and was actually primarily promoted by the Greek physician Galen in the 3rd century A.D. Despite this now disproven settled science of medicine, Galen's work forms the foundation of much of what we now know about human anatomy, physiology and neurology. Even as the Hippocratic theory of humours waned, Galen's theories on anatomy, and particularly, the circulatory system were accepted settled science until the 17th century when English physician William Harvey demonstrated that venous blood did not originate in the liver, but instead, the venous and arterial system were a single system with two (actually four) components. Galen (and Hippocrates) were hampered by law forbidding dissection and investigation of human corpses, and by the lack of technology which would have kept their vivisection subjects alive long enough to completely figure out mammalian physiology. Still, Galen was a scientist; he hypothesized, experimented, analyzed, and constantly revised his theories.
Strangely, the theory of humours almost received verification in the 20th century with the experiments of Otto Loewi, who demonstrated that a fluid collected from the vagus nerve would control the heart rate in a frog. Loewi electrically stimulated the intact vagus nerve, and it slowed the heart. He then took fluid from around the heart, transferred it to a second frog, and the fluid alone slowed the second frog's heart. Was this evidence of humours? Or something else. Fortunately, by this day, Loewi was on the trail of neurotransmitters and hormones –- chemicals secreted by cells in the brain, nerves, adrenal glands, and other secretory organs -- which served to transfer control signals from the brain to the rest of the body. Many of these hormones circulate freely in the blood, much like the humours proposed more than 20 centuries earlier.
We now know much more about medicine and the human body, and we pretty much know where Hippocrates, Galen and others went wrong. When blood collects and settles, it forms four layers: a clot (black), blood cells (red), lymphocytes (white) and plasma (yellow). Hormones do circulate in the blood, and some diseases, and disorders result from a disruption in the normal circulatory, hormonal and even neurotransmitter systems. Still, the theory of humours survived for well over a thousand years -- not universally and not without modification -- but it took more advanced science to disprove this settled science.
The Science is Settled (Blunder # 3) – Dinosaurs were cold-blooded, dumb lizards (with a brain the size of a walnut)
The Chinese were known to have found bones of konglong or "terrible dragons" since the Western Jin Dynasty of the late 3rd century A.D. but it was not until the mid 19th century that English paleontologist Richard Owen coined the term "dinosaur" for the gigantic fossil creatures first reported in scientific journals less than 20 years previously. Until the first American fossil Hadrosaurus was discovered in Haddonfield, NJ in 1858, everybody knew that dinosaurs were four legged giant reptiles. That Hadrosaurus was clearly bipedal upset the early settled science and consensus that had arisen in scant 40 years of this nascent science.
Other blunders which were, for a time, considered settled science included a rather famous "duel" between two 19th century dinosaur hunters. Edward Drinker Cope and Othniel Charles Marsh competed to see who could identify the most new species or classifications of dinosaurs. In a move reminiscent of a particular scientifically contested topic of today, Cope and Marsh schemed, ridiculed, diverted specimens and even publically fought over their dinosaur identifications in a feud that came to be known as the Bones Wars. Marsh accused Cope of incompetence when he pointed out that Cope had reconstructed an Elasmosaurus incorrectly, putting the head at the end of the tail. Marsh, however, was not without fault. In 1877, Marsh reported a new species, Apatosaurus, based only on discovery of a spine. Two years later, Marsh improved the description with an illustration of pelvis (hip) and vertebra (spinal) bones; and then described another species, which he called the "thunder lizard," Brontosaurus¸ based on pelvis, vertebrae and shoulder blade. Within the next 20 years, an intact Brontosaurus skeleton was unearthed and went on display at Yale University. Alas, poor Dino was actually an Apatosaurus -- the two species were actually juvenile and adult versions of the same dinosaur. In a further insult (or karmic justice), the Yale skeleton was not complete, lacking a skull, and Marsh had used a skull from another dig. It took nearly 100 years for the final correction to occur -- the Yale "Brontosaurus" had the body of an Apatosaurus and the head of a Camarasaurus! The history of the Apatosaurus/Brontosaurusmistake is interesting, and I can recommend a nice article about the controversy at the Museum of Unnatural Mystery website at http://www.unmuseum.org/dinobront.htm. The science may have been "settled" at one time, but scientists are human, subject to the same mistakes and petty jealousies of any of us, and this case illustrates those faults very well.
Back to our section title, however... Soon after Charles Darwin published his book, Origin of Species, biologist Thomas Henry Huxley proposed that birds had evolved from dinosaurs. However, the consensus of the time was that dinosaurs were cold blooded lizards, not avian at all. In fact, the flying reptiles -- Pterodactyl and Archaeopteryx are not classified as dinosaurs at all. Yet in the 1970's, discovery of the clearly bird-like Deinonychus, and in the 1990's, the feathered dinosaur remains in China confirmed Huxley's conjecture, and has convinced most of the field to accept this new theory. The final blow to the concept of dinosaurs as cold-blooded lizards comes, starting with Deinonychus and the discovery of soft-tissue impressions (and actual preserved tissue) revealing the structure of inner organs of dinosaurs and leading to theories that at least some dinosaurs were warm-blooded.
The history of dinosaur science is fascinating, and an excellent capsule view of the premise of this article. Science is never settled; scientists are constantly finding new data and revising old assumptions. In addition, scientists themselves are human and can even have some pretty big flaws. By the way, it's been fun researching the material for this essay, and I reiterate my recommendation of the Museum of Unnatural Mystery link provided above. There's some great explanations and Q&A there.
Scientific theories change all the time:
- In the 1970's, scientists predicted global cooling. In the 1990's and 2000's it was global warming, in the 2010's there's again talk of cooling.
- For centuries, gastric (stomach) ulcers were thought to be due to stress, spicy foods and excess stomach acid, until 1984, when Australian physician Barry Marshall drank a culture of Helicobacter pylorii and developed stomach ulcers from the bacteria alone.
- Newton, Einstein and Hawking have each had the final word in the field of Physics -- at least until the next run of the Large Hadron Collider.
- No human could survive transonic speeds... until Chuck Yeager broke the sound barrier; no human could survive the radiation of space... until the Soviet and American astronauts spent days in orbit in the 1960's; no human could survive the passage through or space outside the Van Allen radiation belts... until the Apollo moon missions.
- The pesticide DDT was used to kill mosquitoes, particularly in regions of the world prone to malaria. However, it was proven that DDT to cause the shells of bird eggs to become thinner, thus endangering many species if DDT use continued... until it was determined that the report amount of thinning was actually smaller than the margin of error for the measuring instruments of the time.
- Human memory is mystical and metaphysical, with no connection between the mind and the brain... until it was demonstrated that memory is associated with specific anatomical areas of the brain... and then it was discovered that trained flatworms could be ground up, and molecules extracted and fed to other flatworms who then had the "memory" without the need to learn... except that memory requires specific patterns of anatomical connections, and chemical and electrical signals... until it was found last year that some memories may actually consist of molecules that can be inherited! [But that's a topic worthy of its own article!]
The hallmark of science is that it is always hypothesizing, always collecting data, always testing, and always refining or looking for new theories. In fact, the only indication of a good theory is whether one can make valid predictions with the theory. One successful prediction, however, is not enough -- after all, just one failed prediction negates a theory, one correct prediction simply means the theory works for now, or until a failed prediction or a more comprehensive theory comes along.
In fact, I am often asked how a scientist with a personal religious faith can reconcile evolutionary theory with that faith. My response is that a scientist uses theories all the time. Their job is not to judge the truth of a theory, but rather its utility. As long as a theory is consistent with observations, can be used to test and/or predict the data one has in hand, and successfully predicts results, it is a useful theory. The concepts of truth or belief are irrelevant to the Scientific Method, and should never contaminate the science.
* * *
This brings us to the next phase of this essay—which we will cover next month in Part Two: the fallibility of scientists themselves and the false notion of "consensus in science.”
SOURCE: Why Science is Never Settled, Part One by Tedd Roberts
Tedd Roberts is the pseudonym of neuroscience researcher Robert E. Hampson, Ph.D., whose cutting edge research includes work on a "Neural Prosthetic" to restore memory function following brain injury. His interest in public education and brain awareness has led him to the goal of writing accurate, yet enjoyable brain science via blogging, short fiction, and nonfiction/science articles for the SF/F community.
See Also:Common Misconceptions in Understanding Science II: An Unscientific Mindset Among Scientists