Know your scholars: Pierre Duhem

Pierre Duhem (1861-1916) was a French physicist and one of the most important historians and philosophers of science at the beginning of the twentieth century. While he is best known for his indeterminacy thesis and his conjectures about the history of the Middle Ages, Duhem also made notable contributions to thermodynamics, elasticity, and hydrodynamics.

While researching the origins of statics, Duhem uncovered treatises written by medieval philosophers like John Buridan, Nicole Oresme and Roger Bacon. The sophistication of their work shocked him. Duhem consequently rejected the widely held view that the Middle Ages was a dark age devoid of learning.

He also came to believe that these medieval scholars laid the foundation for much of modern science and even anticipated many of the discoveries of Copernicus and Galileo. Since he published these ideas, historians of science and of the Middle Ages have largely vindicated Duhem's ideas about the worth of medieval scholarship.

As monumental as his contributions were to history, Duhem played an equally important role in the development of modern philosophy of science. In his opus, The Aim and Structure of Physical Theory, Duhem provided scholars with a feast of interesting ideas which are still widely discussed and debated.

One of the the most thought provoking of these ideas was Duhem's challenge to classical reductionism. If you are unfamiliar with classical reductionism, it is the thesis that specific laws of science will be shown to be logical extensions of more general laws. In this sense, they are deduced like a sound conclusion in a mathematics or logic problem. For example, Isaac Newton claimed that he deduced his law of universal mutual gravitation from Johannes Kepler's laws of planetary motion. This led Newton to believe that Kepler's laws are nothing more than his own more general principle expressing itself in a certain situation. 

Duhem challenged this assessment by arguing that Newton's law contradicted Kepler's. More specifically, he explained that the interplanetary mutual gravitational perturbations caused deviations from Keplerian orbits (in layman's terms: Kepler's planetary orbits are slightly thrown off by other forces acting on them. This can include tugs from other planets or resistance from an atmosphere. Newton came up with the calculus and physics that demonstrates this). Since deductive logic requires that we cannot derive a false conclusion from true premises (or if we are trying to show that Newton's law is deduced from Kepler's, a conclusion from contradictory premises), Duhem thought that Kepler's laws could not be deduced from Newton's.

His biggest challenge to reductionism, however, was the Duhem Thesis. This thesis argued that reductionism is not possible because of the methodological differences between physics and the other sciences. Given that physics is the only field in which a single hypothesis can be isolated and tested, Duhem argued, there is no way the other sciences can be reduced to it. They are simply too different in their techniques and experiments to be subsumed into physics. This thesis is often mistaken to be the same as a similar one proposed by the American philosopher, Willard van Orman Quine (1908-2000).

Despite the popularity of this, the two men had very different views on science. Quine's thesis argues that one must make assumptions about a number of ideas to test a hypothesis. For example, one must assume things the laws of optics and planetary motion to test their hypothesis about the rings of Saturn. This means that no hypothesis, not even those of physics, can be done in isolation. Quine is also a realist who accepted the existence of scientific objects like atoms. Duhem, on the other hand, assumed that unobservable things like atoms were "useful fictions" used to make predictions.

While Pierre Duhem's legacy may today be partially (or largely) forgotten, he was a key figure in the history and philosophy of science. His work highly influenced a number of scholars in both history and philosophy, including the great Thomas Kuhn (1922-96).

Why you should about skeptical of "Ancient Aliens"

If you own a tv, you have probably seen the wild haired host of The History Channel's hit show, Ancient Aliens. This man is Giorgio Tsoukalos. Like Erick von Daniken before him, Mr. Tsoukalos argues that aliens helped mankind progress culturally and technologically in the past. For example, aliens could have helped ancient Egyptians in their construction of Stonehenge. Despite being laughed off by professional historians, anthropologists, Mr. Tsoukalos' "ancient astronaut hypothesis (from now on, the AAH)" is taken seriously by large hunks of the public.

To his credit, I think Mr. Tsoukalos' case is a lot more plausible than many other fringe beliefs like astrology and homeopathy. This is because the aliens he posits are entirely physical beings whose existence would not prove scientific naturalism is incorrect. Another reason why it cannot be ruled out a priori is because astrobiologists and the men and women at SETI believe that there is more than likely other intelligent life in the cosmos. This is something that other believers in odd (but natural) beings like bigfoot cannot claim.

Despite being more plausible than a lot of other bunk out there, the AAH still seems to be bunk. Like other fringe beliefs, the proponent of this idea are not formally trained in history, anthropology, or archaeology. Von Dankien was a motel operator. Mr. Tsoukalos has a degree in sports communication. Their theories have also been vehemently rejected by the community of scholars. While these signs do not prove that the AAH is bunk, it should cause us to raise our red flags. My concerns, however, are not historical (those criticisms are out there if you are interested in them). Instead they stem from two major pitfalls that all variation of the AAH I have seen share. 

The first pitfall is that it commits the "alien of the gaps" fallacy. Much like the god of the gaps fallacy, the AAH is nothing more than finding a gap in our understanding and plugging it with a super powerful being. Don't know how the pyramids were built? Aliens did it. Have no idea how the heads were moved at Easter Island? Aliens levitated them. Like all other arguments from ignorance, the alien of the gaps fallacy takes the form of "I don't know how x happened. Therefore, it was y."

Unfortunately for the alien proponent, not knowing how something happened is not evidence for any hypothesis. It is merely a statement of ignorance. To justify the leap to "aliens did it," Mr. Tsoukalos is going to need positive evidence. After he has this, he is going to have to show that the AAH adequately explains it. This demand is very similar to what many philosophers of science, like Gregory Dawes and Maarten Boudry, expect from intelligent design advocates. If the AAH is the best explanation, then it should possess the following traits (source) :

1. Testability: better explanations render specific predictions that can be falsified or corroborated.
2. Scope (aka “comprehensiveness” or “consilience”): better explanations explain more types of phenomena.
3. Precision: better explanations explain phenomena with greater precision.
4. Simplicity: better explanations make use of fewer claims, especially fewer as yet unsupported claims (“lack of ad-hoc-ness”).
5. Mechanism: better explanations provide more information about underlying mechanisms.
6. Unification: better explanations unify apparently disparate phenomena (also sometimes called “consilience”).
7. Predictive novelty: better explanations don’t just “retrodict” what we already know, but predict things we observe only after they are predicted.
8. Analogy (aka “fit with background knowledge”): better explanations generally fit with what we already know with some certainty.
9. Past explanatory success: better explanations fit within a tradition or trend with past explanatory success (e.g. astronomy, not astrology).

Since the AAH does not possess these traits at the present, we are more than justified in not accepting it. If you are interested in researching this topic more, philosopher of history C.B. McCullagh beautifully elucidates how explanations work in history in Justifying Historical Descriptions.

The second flaw in the hypothesis can be understood through a challenge. I submit to Mr. Tsoukalos that "there is an alien in my garage" and dare him to disprove this statement. If he were to walk to my garage and open the door, he would point of there is no alien. I would respond by saying that "the alien is invisible." Next he would try to feel it. I would allege that the alien is incorporeal. Finally, he would say "lets try to detect its body heat." I would state that the alien has on a shield that emits no heat.

Much like the alien in my garage, the AAH can always add ad hoc (auxiliary) assumptions to avoid being proved wrong. For example, a retired construction worker named Wally Wallington has single-handedly built a Stonehenge replica in his backyard (link here). What makes this interesting is that Mr. Wallington used nothing but very simple tools that would have been available at the time of the Celts. This shows that one can move and erect very heavy stones without the assistance of ancient aliens.

Do proponents of the AAH take this as evidence that their hypothesis is wrong? Of course not. Like my garage dwelling alien, the AAH can be insulated through tacking on auxiliary assumptions. The aliens proponent will respond to Mr. Wallington's Stonehenge by saying "OK, well how about this other giant thing?" or "well, the aliens helped them do the step before that." The problem with this strategy is that prevents the AAH from being testable in any meaningful way. Since this sensitivity to testing is one of the core characteristics of science, the AAH falls into the same pit of bunk as creationism and Freudian psychology.

The AAH proponent may respond to my charges by saying "that does not conclusively disprove that there was no ancient aliens. It is still possible." I agree with this statement. Despite being a bad explanation and that suffers from being untestable, it is still possible that there were ancient aliens. This response, however, misses the point. Science does not seek to know that is merely possible. This is because everything that is not logically impossible is possible. This includes the possibility that hyper-dimensional beings are living inside your butt and that there is an actual, undetectable alien living in my garage.

Instead, science wants to know what ideas and explanations are the most probable. This is how science came to embrace its most important ideas, like evolution, the periodic table, and thermodynamics, and reject things like astrology and Tarot cards. It is also how any cogent form of inductive reasoning works and how we judge events at our college and jobs. If the AAH wants to be taken seriously, it must conform to these standards because they are the most successful ones we have.

If you would like to know more about the AAH and many other ideas, I highly recommend Guy P Harrison's 50 Popular Believes that People Think are True. This book is very fun to read and contains lots of recommendations about further resources.

What do skeptics believe in?

When my fellow skeptics or I interact with believers, we are almost always asked the question: “Well if you do not believe in x, what do you value or believe in?” For some reason, people assume our answer will be: “Nothing. I do not appreciate anything or believe that there is anything interesting left to say about life.”  Since this stereotype is as popular as it is inaccurate, I decided to outline my own response in this post.  If you are a skeptic and also have a blog, I recommend you take the time out of your day to sketch out your own response.

I believe in the negative value of philosophy.

While philosophy may not give us knowledge, it provides plenty of wisdom.  This wisdom helps us realize how worthless many popular fetishes and activities really are.  This realization comes about through philosophy’s insistence that we need to think deeply about things like God, free-will, and right and wrong.  Since contemporary culture consists almost entirely of quick and shallow answers, philosophy’s contrary way of thinking helps us see through its vanities quite easily.

After fetishes like reality TV shows, celebrity gossip, chain restaurants, and New Age self-help nonsense are all cleared away, we can prioritize those things that are left.  Since I started doing this, I have accomplished things ranging from learning how to cook better to studying abroad in Russia for a semester.  I have also read a book a week (on average) for over ten years.  You would be surprised what you can do in the extra time you have from not watching so much television.

The “negative” value of philosophy will become even more important in the United States (and the world for that matter) as its population becomes increasingly nonreligious.  Philosopher Richard Taylor outlined this need in his book, Metaphysics.

When religion can make no headway, in the mind of the skeptic, ideology came sometimes offer some sort of satisfaction to much the same need.  Thus many persons spend their lives in a sandcastle, a daydream, in which every answer to every metaphysical question decorates its many mansions.  The whole thing is the creation of their brains, or even worse, of their needs—it is an empty dream, for nothing has been created except illusions (Taylor, 5).  

These beliefs, such as New Age philosophies and reality TV shows, are just as shallow as the traditional beliefs systems they are replacing. Like Richard Taylor, I believe this becomes apparent when we study philosophy.  

Since Socrates, philosophy has been about tearing down destructive aspects of Western culture.

I believe that the cosmos is wonderful without making stuff up about it.

Since I was a child, stars and planets have filled my imagination. I had posters of the planets all over my walls and read encyclopedias to learn everything I could about space. The beauty and size of the cosmos blew my young mind and induced a feeling of great awe. Since this time, I have never had these feelings replicated by anything else.

Despite what many New Age'rs and creationists think, understanding the science which underlies the workings of the universe does not undermine my cosmic awe. On the contrary! Science lead me to the profound truth that we are all connected “to each other, biologically. To the earth, chemically. To the rest of the universe atomically.”

This shows that one does not need to turn to astrology or our tarot cards to feel the majesty of the universe. In fact, celestial courts are quite tame in comparison to the true wonders of space. The beauty and power of pulsars and quasars is wilder than anything dreamed up by an ancient soothsayer.  Like other space geeks, I’m rocked to my very core by the images and data retrieved by the Hubble telescope. Its images put any man made piece of art to shame. 

I believe if this sort of information was available in the past, almost all great works of art would be popularizations of science. Can you imagine a universe where Leonardo Da Vinci would have seen these pictures? I think he would have given up his other works and spent the rest of his days working on telescopes, painting palace ceilings with black holes and galaxies, and running the first ever Florence Astronomical Society.

I believe that critical thinking can be learned

When I was a teenager, I believed in all sorts of weird things. This stemmed from me never going past surface level depth in traditional religion. Unlike many Americans, I was never taught the Bible or theology, but a moot Christianity. In 8th grade, I began exploring the marketplace of ideas. For a while, I was what could have been described as a New Age'r. I routinely visited pagan chat rooms and read material on occult.

As I grew older, my education began to get in the way of my belief in weird things. In particularly, reading Michael Shermer. By 2008, I could no longer separate the way I thought in oceanography and symbolic logic from my everyday thinking.  Critical thinking had infected my mental faculties, which induced my first real intellectual crisis.  This soon changed as I started to explore skepticism through the internet.  I came to love the works of James Randi and other skeptics.

The way they used logic and scientific thinking to explain psychics, UFO’s, and big foot struck me as a potent way of viewing the world.  By applying these logical and scientific rules of thumb, I started to notice the nonsense on tv almost immediately. Things like political and pseudo-scientific scams became transparent and I no longer fell under their sway.  I officially began to forsake comforting fantasy for clear thinking and reality.

Despite the alarming beliefs of most Americans, I believe that critical thinking can be taught. I and the countless other members of the skeptic movement are proof.  Our demand for belief has greatly enhanced our lives. Clear thinking gave me and other skeptics a greater appreciation of reality. As Carl Sagan once said, “it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.”

Concluding thoughts:

In conclusion, I and many other skeptics believe a lot of things, such as the value of philosophy, the beauty of the cosmos, and that critical thinking can be learned.  If you want to know what else I believe, I recommend you read through the other posts on this blog or read through Carl Sagan’s classic, Demon Haunted World.

Excellent skeptical documentary

The Enemies of Reason is a 2007 skeptical documentary that was hosted by Richard Dawkins and produced by the BBC. It covers many anti-scientific and pseudoscientific beliefs like homeopathy, astrology, spiritualism, dowsing, and postmodernism. If you are looking for a way to get your friends into skepticism, this documentary is fun to watch and highly informative.

How pervasive is belief in weird things?

If there is one thing that skeptics are obsessed with, it is investigating weird things (by weird things, we mean the paranormal, urban legends, conspiracy theories, etc…).  Many of us spend a good bit of time going to conventions, listening to podcasts, and reading up on everything from big foot to perpetual motion machines.

To non-skeptics, our fascination with weird things way seem a bit odd. After all, we generally don’t believe this sort of stuff, so why would we spend so much time thinking about aliens and astrology? The reason is simple. For a very long time, belief in weird things has pervaded our culture. When we go to check out at the grocery store, we see our monthly horoscopes.  When we go over to our friend's house, they try to convince us that alternative medicine cured their cold.  When we turn on the television, we see a show with “experts” talking about how aliens built the pyramids. To the reality obsessed skeptic, this cultural stranglehold is unacceptable.

You may object to our disgust and write these beliefs off as just a few people having some harmless fun. Unfortunately, this type of sentiment could not be more wrong. Not only are these beliefs harming people (which will be the subject of another post), but they are incredibly common. For example, a 2001 Gallup poll shows that many Americans believe in the paranormal and the occult. Some of these numbers include:

• 52% astrology
• 46% extrasensory perception
• 19% witches
• 35% ghosts
• 22% aliens have landed on Earth
• 67% actually had a psychic experience.
• 42% communication with the dead. 

Upon seeing these numbers, you may wish to dismiss them.  “That poll was conducted over twenty years ago.  There is no way that many people still believe in such nonsense.”  It should be noted however that a more recent 2005 Gallup poll shows that 3 out of 4 Americans believe in the paranormal. This includes: 

• 41% ESP
• 37% haunted houses
• 32% ghosts 
• 31% telepathy
• 25% astrology
• 21% witches

If this has not scared you by now, it gets even worse.  The aforementioned numbers and anecdotes do not even scratch the surface when it comes to weird things. Some other prevalent beliefs that I have yet to mention include: dowsing, the Bermuda triangle, homeopathy, auras, reiki, fung shui, tarot cards, Nostradamus, Bigfoot, the Loch Ness monster, creationism, intelligent design, planet Nibiru, JFK assassination conspiracy theories, global warming denial, holocaust denial, emotions in plants, perpetual motion machines, astral projection, ghost hunting, and anti-vaccination hysteria.

For example, a newer (but more narrow) poll by Fairleigh Dickinson University shows that "36 percent who think that President Obama is hiding information about his background and early life, 25 percent who think that the government knew about 9/11 in advance, and 19 percent who think the 2012 Presidential election was stolen (link)." Wow.

With all of these beliefs everywhere, you may be wondering, how do I talk to people about these beliefs without sounding like a dick? For the answer to this question, you will have to wait for another blog post. In the meantime, I recommend reading two books that will help you answer some of the most pervasive weird beliefs that people have.  These are Richard Wiseman’s Paranormality and Michael Shermer’s Why People Believe Weird Things. Both works cover the arguments used by proponents of weird things and the psychological faculties that make them possible in the first place.

A very brief primer on skepticism

Skepticism is nothing new. In ancient Greece, Pyrrho of Elis (360-270 BC) questioned everything and withheld assenting to all beliefs. The Roman Sextus Empericus (160-210 AD), who idolized Pyrrho, took skepticism one step further and developed a very sophisticated methodology for questioning the foundations of all types of knowledge. This school of skepticism, known as Pyhrronism, sought to free minds from the disturbance of unfounded beliefs. Much later, one of the greatest modern philosophers, David Hume (1711-1776 AD), drank from the same fountain as these ancients. Although he had positive philosophical beliefs and contributed to fields like economics, history, and proto-psychology, Hume laid siege to many sacred cows like causation, foundationalism, the design argument, traditional ethics, and miracles.

These Pyrrhonian skeptics, despite their brilliance, did not get too far when it came to attaining positive knowledge about the world around us. This is because their skepticism was predominantly focused on tearing down or undermining knowledge. Not constructing it. Scientific skepticism differs from this philosophical skepticism because it is not satisfied with merely questioning beliefs. It also wants to find out the how the world actually works and which methods are best for exploring it. To succeed at this task, the skeptics of our age have embraced, as Michael Shermer put it, "the most powerful tool ever devised for understanding how the world works." This tool is science. 

What impresses skeptics about science is its long track record of successful prediction and potent application in fields like computing, medicine, and engineering. In the short time since the Scientific Revolution, science has explained the origin of species and shown us that our Milky Way galaxy is one among billions and billions. Most notably, it has eradicated diseases like Polio, made instantaneous communication around the world possible, and put men on the moon. The skeptic is equally as impressed by science's methodology. Unlike traditional ways of looking at the world, science is built on probability rather than certainty. This means that all knowledge in science is fallible and can be revised if new information becomes available. This track record and its openness to new ideas is why skeptics are confident that science is the way to go.

Science has many valuable lessons to teach us. It stresses the importance of admitting when we do not know something, it uses Ockham's Razor to shave off auxiliary assumptions, it requires that we know how to tell the difference between legitimate and illegitimate resources, and makes us demand extraordinary evidence for extraordinary claims. When we put these virtues, along with knowledge of cognitive biases, logical fallacies, and the history and philosophy of science, into a toolkit, we get a non-domain specific form of reasoning called "scientific skepticism." This toolkit helps us inspect a vast array of weird things like the laws of thermodynamics, haunted houses, homeopathy, and the idea that humans are distantly related to corn. It places them on a truth continuum which ranges from almost certainly false to almost certainly true.

It is true that all of this knowledge is not certain and may be revised, but it would be mistaken to think that this allows us to not take any of these ideas seriously or that we can believe whatever we want. There is so much evidence and corroboration for the ideas on the "almost certainly true" part of the spectrum (evolution and thermodynamics) that it would be perverse not to accept them. Likewise, the evidence points very strongly against ideas on the "almost certainly false" part of the spectrum (haunted houses and homeopathy). Our tendency to place all sacred cows on this continuum according to their supporting evidence has led to my fellow skeptics and I to be called "rude," "cynical," or even"close-minded."

While it may not be polite, we skeptics value the truth above all else. As Carl Sagan once said, "it is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring." If we do not, as Carl Sagan asks us, seek the truth, then we are susceptible to being taken advantage of by others. Every year, thousands of dollars are thrown away calling psychics and reading horoscopes. Think of all of the people this money could have fed or how many people it could have put through college. In some cases, people die from using faith-healing (no, I am not kidding). If only these people would have been more skeptical, their lives could have been saved.

If this view of the world sounds interesting to you, then I highly recommend reading Carl Sagan's essay The Burden of Skepticism. This essay beautifully written and is full of lots of great information. You can also check out Brian Dunning's Here Be Dragons. This 40'ish minute video fleshes out a lot of the points made in this article (it is also classroom friendly).