The Case for Scientific Skepticism

The reason scientific skepticism developed is that the world is complicated. It’s subtle.

Everybody’s first idea isn’t necessary right. Also, people are capable of self-deception. Scientists make mistakes, theologians make mistakes, everybody makes mistakes. It’s part of being human.

So the way to avoid mistakes, or at least reduce the chance you’ll make one, is to be skeptical. You test the ideas. You check them out by rigorous standards of evidence.  

I don't think there is such a thing as a received truth. But when you let the different opinions debate, when any skeptic can perform his or her own experiment to check some contention out, the truth tends to emerge. That’s the experience of the whole history of science. 

It isn't a perfect approach, but it’s the only one that seems to work.

Except from Carl Sagan's Contact

A Brief History of Painting

In this post I try to decipher the seemingly inexplicable art of painting, by identifying the original ideas used by the artists. For the purposes of this discussion, by “painting” in this text I refer to western painting between 1200 and 1900 AD.

As an electrical engineer I know next to nothing about art history. I was never educated in art beyond high school classes, my own reading on the subject, and discussions with more knowledgeable friends.

  

For over 10 years I was visiting art museums, ever since I left Greece in 2003 for the US. In my travels I got to visit many major museums in the US and Europe. While I was admiring the aesthetics of what I was seeing, I never bothered to explain it in a scientific manner, i.e. attempting to establish rules and patterns that would explain the creative choices made by the artists. I had assumed it couldn't be done.

A couple of years ago I got to read Ernst Gombrich’s “The Story of Art”. It was a revelation for me, because suddenly all the art I had been witnessing in the past few years suddenly made sense. It turns out that aesthetics had not been the main worry of the painters at the time. Rather, they were problems solvers in a similar way that scientists today are problem solvers: They were faced with immense challenges and the artists tried for centuries to tackle them.

This post attempts to explain why painting evolved the way it did. How did we start from the religious paintings of the 12th and 13th century and how did we progress through the Renaissance and into the Impressionists?

I spent the last few months researching more books and finding the right paintings that exhibit the reasonable progression I was looking for. I did not find it. I believe this happened mostly for two reasons. First, as with any complex subject, the evolution of painting is nonlinear. Second, I have yet to come across an art history book that is written for an engineering audience (i.e. in a clear, objective manner). This is why I never found that the museum labels attempting to provide information next to paintings ever provided any useful insight to me.

Had I picked paintings from all around the world, it wouldn’t have be much help since most people (including myself) do not have access to multiple museums. However, there are a handful of museums around the world with collections so vast that they have almost every aspect of the history of painting I was looking for.

The 19 paintings I have picked to go through the story of painting can all be found in the National Gallery in London. Note that these are not necessarily the most famous works of art of the museum, just the ones that are most relevant to our story.

So, let’s begin our journey in time.

Forget every painting you’ve ever seen in your life.

Tabula rasa.

If you were an alien visiting earth around 1200 AD, this is typical of what you would see painted around Europe:

1. Virgin and Child enthroned by Margarito d’Arezzo (1262), Rm51

At the time the church was triumphant in people’s lives. They rule the social gatherings; they are one of the main activities in the everyday life. A church was usually the only stone building in the town. And renaissance hasn’t kicked in yet, so science is still in the dark ages. God is almighty and the Bible is a holy book by which everyone abides.

The paintings at the time reflect this reality. They are writing, in pictures. They are two-dimensional cartoon caricatures, transferring almost word-for-word the stories in the Bible. People are afraid to mess with God, and they try to convert to images as faithfully as possible whatever they read. Everything is carefully placed, telling the same biblical stories, and everything is 2D.

Things start changing for the first time with the appearance of Giotto:

2. Pentecost by Giotto di Bondone (1310), Rm51

Giotto was one of the first artists that attempted to infuse some realism into his work. While that painting looks mostly flat, notice the ceiling: Giotto is trying to include perspective in his work, resembling how a real ceiling would look like. Giotto tries to represent depth on a flat surface.

Artists are now striving to improve the sense of depth on paintings. While this three-dimensionality is something we are used to it today, back then it was not obvious at all how one could achieve that effect.

3. The Wilton Diptych (1395), Rm53

Around the year 1400 artists started being able to handle depth better. In order to achieve perspective, two main effects must be present: First, objects should get smaller the farther they are away from the observer. Second, for an object at a given distance, lengths along the line of sight should be shorter than the lengths perpendicular to the line of sight. This is called foreshortening, and it is displayed in the above painting beautifully in the sitting angels next to the Madonna. It provides a 3D feeling of the person, breaking away from the 2D images of the past.

This change did not happen by accident – it was led by a big technological advance of the era: optics. People started to master geometry, light rays and lenses. The first eyesight correction lenses appear in Europe around that time, and this is also evident in paintings such as the Wilton Diptych. We are getting closer to solving the problem of depth on a flat surface.

At the same time, artists realize that in order to break away from the tradition of the church, they need to find new themes. The painters, armed with the tools of perspective geometry, start to paint fragments of the real world. Painting is no longer just for bringing the Bible into life, but displaying life.

4. The Battle of San Romano by Paolo Ucello (1438), Rm54

Uccello was obsessed with perspective. In the above work (which consists of two more parts), depicting a battle between the Florentine and Sienese forces in 1432, he spent days to succeed in foreshortening the man on the ground on the bottom left. He occupies as much vertical space as horizontal, despite that he should appear twice as long from head to toes than along his arms. Also notice the dropped pieces of weapons on the ground, all pointing in the same vanishing point, as well as the smaller people and horses in the background. This one of the first paintings that depict perspective so strongly.

Now take a look at this next painting:

5. The Arnolfini Portrait by Jan Van Eyck (1434), Rm56

You should immediately observe a vast difference in the style, and a much more realistic depiction of people and environments compared to the previous paintings. This was caused by another technological advance: oil painting. Up until that point in time artists (mainly in the Italians) were using eggs as the main ingredient of their paint (Egg Tempera). They would mix eggs with colored pigments to create the different colors. The method, used by almost everybody up to that point, has two major drawbacks. First, Egg Tempera dries fast and there is no time to waste when painting. Second, it is thick and does not allow fine details on the canvas.

Van Eyck, coming from the Netherlands, discovered a method for using oil to paint on wood. This has dramatic effects in the types of paintings that are possible. In the Arnolfini Portrait, the slow drying oil allows Van Eyck plenty of time to meticulously paint every detail of the couple, capturing as much of reality as possible, In addition, the thin structure of oil allows him to painting minute details, particularly the hair of the dog in front of the couple. Van Eyck has also mastered the technique of perspective, creating a very realistic painting, a “hole in the wall”.  (If you zoom into the mirror in the wall behind the couple, you can even see Van Eyck’s reflection painting the couple).

By Van Eyck’s time, the mid-15^th century, the problem of depth was pretty much resolved. However, the challenge of depicting realistic people on a canvas remains unsolved. Looking at the Arnolfini Portrait, the people look detailed but not realistic. They are more like wooden statues rather than breathing and living people. Furthermore, there is the problem of harmony: how do you place people and objects in a canvas so that the overall impressive is aesthetically pleasing and doesn’t look awkward?

The next painting illustrates the challenging nature of these problems.

6. Martyrdom of Saint Sebastian by Piero del Pollaiolo,(1475), Rm57

This painting handles perspective well. But, there are significant issues with the realism of the people and their placement. The people (Pollaiolo probably used the same person painted in different positions) still look like wooden statues. While their bodies are more realistic than what we’ve seen until now, they feel fake. Also, Pollaiolo, like most of his contemporaries, is struggling to place them in the frame in a harmonious manner. He is trying to form a pyramid, and in order to provide some complexity he flips the orientation of the two corner-most archers (one is facing forward, the other backward). He does the same with the two archers in the front and middle, who reload their bows. However the final result is less than satisfying. Furthermore, the background feels disconnected with the foreground action.

The problem of the realistic human body and the problem of their harmonious placement were obsessing the artists of the time. Year after year, the artists would sit down and discuss with each other in their workshops, trying different things, struggling to find solutions to these issues that prevented painting from reaching perfection. Yet these problems would remain unsolvable for another 30 years.

In their attempts to reach perfection, the Italians wanted to break away of the old traditions of the church themes. They wanted to be more like the ancient Romans and Greeks, which achieved perfection in sculpture almost 2,000 years before.  “We should be as good as the ancients”. And so the themes start shifting away from the church try to gain inspiration from the ancients.

This is the renaissance, the rediscovery of the ancient perfection. The first famous proponent of this shift is Botticelli.

7. Venus and Mars by Sandro Botticelli (1485), Rm58

Botticelli was the first to solve the harmony problem, by carefully placing the people in the canvas, His most famous work that exhibits this effect is the Birth of Venus, but it is also evident in the painting above. The position of Mars and Venus along the canvas feels natural, filling the space without awkward spots.  Their arms feel naturally placed. Botticelli has also improved the anatomy of the bodies, bringing them closer to reality.

And yet, even Botticelli cannot solve the wooden statue problem. The people still don’t look real, even though Botticelli tries to tackle the problem by the exquisite details in the drapery of Venus’ dress and the curly hair in both lovers. He sacrifices some accuracy in favor of life-likeness, but despite his attention to detail, just like Van Eyck and Pollaiolo, he doesn’t succeed.

The solution to the realism problem though was just around the corner.

The 16^th century is considered by many to be the greatest period in the history of art. Driven by scientific advances (mastering geometry and the science of perspective, as well as the anatomy of the human body), for the first time humans succeeded in portraying other humans on a flat surface in a realistic manner.

The man who solved the problem was Leonardo da Vinci.

8. Virgin of the Rocks by Leonardo da Vinci (1508), Rm57

Leonardo barely completed 10 paintings in his lifetime. He painted the Virgin of the Rocks twice though: one painting can be found in the Louvre in Paris and the other in the National Gallery in London.

Hundreds of people attempted to solve the wooden statue problem for human figures. Van Eyck in his Arnolfini portrait spent huge amount of time attempting to replicate every little detail of the real world onto his canvas. Botticelli in his Venus and Mars work tried to make more anatomically accurate bodies, and by adding wavy hair in his subjects and draperies in their clothing. But none of these ideas worked. The more they attempted to mimic reality, the more they failed.

And here lies Leonardo’s genius: he realized that in order for a human body to appear more realistic, you must paint it less accurately. You have to leave something for the imagination. If you add too many details, it feels more fake.

The most critical elements in a human face are the eyes and the mouth. Leonardo introduced his sfumato technique, whereby he didn't draw these elements with clear lines, but with a foggy style, introducing shadows around the edges. This is very apparent in the Mona Lisa, but also in the Virgin of the Rocks:

Unlike Botticelli and van Eyck, Leonardo painted the eyes and mouth of the Madonna with foggy edges instead of clear outlines. This lets our mind add a sense of realism and motion: it is just enough detail our brains to make it real.

The Virgin of the Rocks is a prime example of solving all the major problems that plagued painters for centuries: it has a harmonic placement of bodies; it adds a natural third dimension via mastering the laws of perspective; and it includes realistic human bodies that look and feel like real people.

(It is interesting that the ancient Greeks utilized similar logic when building the Parthenon, the so-called optical refinements. They realized that for a building to appear perfect, it has to be slightly imperfect. That’s why the Parthenon has subtle curves, such as the columns being thicker in their middle and the floor being concave in the center of the building. As with Leonardo, to achieve perfection, one has to take into consideration the physiological effects of human brain perception).

Once Leonardo’s method appeared, it gained immediate acceptance and was copied successfully by numerous artists.

9. The Garvagh Madonna by Raphael (1510), Rm8

Raphael arrived in Florence when the titans Leonardo and Michelangelo reigned supreme, and yet he developed his own style and produced works on par with theirs. He perfected the placement of bodies, the harmony in a painting, and he put together the most astonishing compilations. His Madonna paintings defined her face for the ages to come (much like Michelangelo’s Creation of Adam defined the face of God as an old bearded man). He also dared to break away from the tradition of static, strict religious paintings and arranged them in playful and more complicated ways, something that was unimaginable until a few years before.

10. Ariadne and Bacchus by Titian (1520), Rm12

This is another example of the perfected painting techniques that appeared in the first half of the 16^th century. It depicts the scene when Ariadne, being abandoned by Theseus on the island after helping him getting through the Minotaur’s maze (his ship is seen in the left edge sailing away), wakes up to find Bacchus (the God Dionysus) jumping off his chariot, having fallen in love with her. The painting is divided in two parts, the top left triangle with the sky and the sea, and the bottom right that shows Bacchus’ company. The painting is alive, natural, harmonious, and pleasing.

11. Adoration of the Kings by Jan Gossaert (1515), Rm14

This is again a Northern painter, as indicated by the cleaner lines compared to the Italian artists. However this painting is a true “hole in the wall”, with incredible 3D perspective and vibrant colors. Harmony is again achieved in the placement of the people, angels and animals, creating a spectacular arrangement.

By the year 1520 people thought that painting had peaked. It had solved all the major problems, mastering perspective, harmony, and realism. People thought that art was finished. How could one surpass the achievements of Leonardo, Michelangelo, Raphael and the other masters?

Now artists were faced with a new problem. Is there anything that they could differently to create the next generation of paintings?

Here are a few ideas that people attempted.

12. St. George and the Dragon by Tintoretto (1555), Rm9

Tintoretto took the much-painted story of St. George killing the dragon, and twisted it by having the dragon fight in the background and the fleeing princess dominant in the foreground, also adding a spectacular apocalyptic sky.

13. Virgin and Child with Saints by Parmigianino (1540), Rm2

Parmigianino decided to take further liberty (almost heretical) with the concept of the Madonna and Jesus. He painted a strange Madonna, with elongated neck and arms, while Christ and St. John are playing and disrespectfully ignoring her. These decisions would have been unthinkable in the pre-Leonardo era.

14. The Ambassadors by Hans Holbein the Younger (1533), Rm4

This is one of my favorite paintings. Holbein decided to create photorealistic portraits, and his original idea was to infuse them with personality, providing information to the beholder. He also chose non-religious themes and unconventional placement of his subjects. In the Ambassadors he added numerous clues, including scientific instruments, a globe of the earth and another globe of the skies, books and notes, and a cross to signify the people’s mortal nature hidden in the top left corner. Most impressive of all is the anamorphic skull in the bottom part that only looks correct when the painting is viewed from a bottom right location.

15. A Windmill by the River by Jan van Goyen (1642), Rm16

Van Goyen tried something even more radical: he completely removed human subjects from his paintings, depicting landscapes and the complex Dutch skies. This is one of the first paintings that does not include any people.

16. Self portrait at the age of 63 by Rembrant (1640), Rm23

Here we have Rembrandt, who, armed with Leonardo’s fuzziness idea, took it to the next level by sacrificing even more accuracy for life-likeness. His portraits are by no means photorealistic, and yet they are warm and natural, creating the impression that we know these people very well.

17. A Young Woman Seated by Johannes Vermeer (1670), Rm26

Vermeer chose yet another path: instead of painting religious topics or impressive scenes, he opted to paint everyday life moments. In this work it’s just a young lady playing her piano. Almost all of his paintings show the same two rooms and the same people.

18. The Experiment with the bird in the air pump (1768), Rm34

As I've mentioned before, this is my favorite painting in the museum. Notice that the year is 1768, well into an era that science and technology started entering normal people’s lives. This is the middle of the 18th century. Newton, the founder of modern science, had lived the century before. Galileo, too. This is the era that marks the beginnings of science, which will lead to the industrial revolution and then onto the modern world.

The painting depicts a scientific experiment. These air pump devices were common in the 18th century. Scientists would use them to demonstrate that a candle's fire goes off after the air is removed, or that it is impossible to hear a ringing bell in vacuum. Joseph Wright chooses here a much more powerful experiment: a bird is placed in the chamber, and as the air is removed the bird starts suffocating, flapping around. The operator is looking at us, as if he needs our opinion: "Should I go ahead and remove all the air and see the air dying, or should I put the air back?"

This is an era where the physicists are still called natural philosophers, because physics is just starting to form as a science. It is the first time that science starts affecting people's lives, pulling them out of the middle ages.

How to communicate science though? Most people are still illiterate, and they can barely read. Communication media are extremely limited. Thus, Joseph Wright chooses to prepare a painting about science.

This painting is one of the earliest depictions of modern science in art.

These last few examples demonstrate that for the next 300 years after the “peak” of the early 1500s, artists were afraid to break from the tradition of the masters. This period lasted way too long, and it posed a new problem: was there another new way to paint, or should the artists be satisfied with minor tweaks upon the perfection that was achieved earlier?

The movement that finally broke the tradition was impressionism.

19. Sunflowers by Vincent van Gogh (1888), Rm45

Impressionists painted not an actual, realistic image of the real world, but rather its impression, i.e. how it feels to the beholder. The shapes depicted resemble real world objects more loosely than ever before. The artists paint the idea of an object, rather than the object itself.

Today we are used to the existence of the impressionist paintings. However back in the 19^th century impressionists were considered crazy and were disrespected because they dared to break away from the traditional rules of painting set in the renaissance.  Van Gogh, famously enough, never managed to sell a single painting in his lifetime.

Today, however, impressionism is regarded as one of the finest moments in human art history, exactly because it is the culmination of multiple unconventional ideas about painting. No one before the impressionists dared to paint something that deviated from reality, as the purpose of painting was to replicate the realism of the world around us.

This, of course, begs the question: why did impressionism arise all the sudden in the 19^th century? Why that particular period in time? What triggered its explosion?

The answer is, once again, a technological one:

Photography.

Photography was invented and developed in the first half of the 19^th century. Suddenly, painting was in a huge crisis: photographs captured the real world in perfect detail and with great ease. There seemed no reason to paint anymore. If the purpose of painting was to capture the real world, photography could do that much better.

Only after photography replaced painting as the recording medium of the visual world did the artists finally break free from the traditional rules and purposes of painting. There was no pressure anymore to try to paint a realistic vision of the world. And thus, impressionism naturally sprung as a new direction of painting, driven by the idea that an artist no longer had to be realistic.

Our journey concludes with this fine example on how technology affects art.

Epilogue.

Painting continued well into the 20^th century, entering the modern era. However I cannot make sense of modern art. It is much more random, driven by impulses rather than from reason. I have not found a coherent explanation yet.

The history of painting is a tremendously complex endeavor. All I have done in this story is to illustrate a pattern that permeates some major works of art. It is nowhere near being a complete explanation of the history of all painting around the world, something that is probably impossible. Painting (or any expression of human intellect, for that matter) is as complex as the human nature itself.

 All images retrieved from Wikipedia,

An Experiment on a Bird in the Air Pump

The are two reasons why I love the above painting by Joseph Wright of Derby from 1768.

First, the painting depicts a scientific experiment. These air pump devices were common in the 18th century. Scientists would use them to demonstrate that a candle's fire goes off after the air is removed, or that it is impossible to hear a ringing bell in vacuum. Joseph Wright chooses here a much more powerful experiment: a bird is placed in the chamber, and as the air is removed the bird starts suffocating, flapping around. The operator is looking at us, as if he needs our opinion: "Should I go ahead and remove all the air and see the air dying, or should I put the air back?"

The attendees' expressions are very interesting. The two girls can barely keep their eyes on the suffering bird, while the rest watch very carefully. With the exception of the two lovers on the left who completely ignore the situation.

Second, it is very interesting to know why the painting depicts the scientific experiment.

This is the middle of the 18th century. Newton, the founder of modern science, had lived the century before. Galileo, too. This is the era that marks the beginnings of science, which will lead to the industrial revolution and then onto the modern world.

This is the first time in history that people start becoming aware of science. It is an era where the physicists are still called natural philosophers, because physics is just starting to form as a science. It is the first time that science starts affecting people's lives, pulling them out of the middle ages.

How to communicate science though? Most people are still illiterate, they can barely read. Communication media are extremely limited. Thus, Joseph Wright chooses to prepare a painting about science.

This painting is one of the earliest depictions of modern science in art.

This painting is an effective method to communicate a scientific idea to society.

For all intents and purposes, this painting is the 18th century version of a PowerPoint presentation.


You can admire the painting in London's National Gallery.

Science is not a democracy

In my last post I argued that believing in an anthropomorphic God is not a choice, where the two options are of equal value. This is because there is no reliable evidence yet on the presence of an earthly supernatural being.

Robin Ince recently wrote along similar lines:

There is a gaggle that seems to consider that expertise is an unfair advantage, that all opinions are equal; an idea that people who are experts in climate change, drugs or engineering are given unfair preference just because they spend much of their life studying these things. I do not think it is fascism that heart surgeons seem to have the monopoly of placing hands in a chest cavity and fiddling with an aorta.
We should not trust people just because they are experts, but if we are not prepared to put the time and effort in to understand something, [...] then we are placed in a position where we must defer and try and make the best decision we can as to who we should defer to.

Science is not a democracy; it's an evidence-based meritocracy. It's closer to fascism than a democracy, with the major difference that the expert/fascist earns his status through the scientific method, and not because of circumstances or strength (physical, political, or otherwise).

In science we do not vote or make decisions based on popular choice. There is no choice. At some points in time most people believed that the earth was in the center of the solar system, that matter cannot cross walls, that the universe was eternal and static. But it didn't matter. What matters is what's right and what's wrong.

Apology to theists

I am an atheist.

I used to think that believing in God or not was a choice. I admired people that didn't, and didn't care about people that did.

Not anymore. I have come to think that believing in God should have a definite answer, in the same way that whether the earth is flat has a definite answer. Sure, you can choose to believe that the earth is flat, but that's wrong. It's not a choice.

No one is born an atheist. We have no reason not to believe in God, and atheism is a state that needs effort to be reached.

I, and millions other people, have reached that state through education, scientific reasoning, logical deductions, and by just plainly looking at the data. It boils down to a lack of evidence for the existence of a God.

(God, in this piece, is the supernatural anthropomorphic know-it-all old man sitting in the sky and watching us all. There are other forms of God which can be fine.)

Now here's the thing: In today's world, I don't think this is a choice anymore. Any person who is educated, can reason scientifically and deduct logically, should reach that same conclusion. There is no excuse anymore in our hyper-connected western world with ultra-fast communication systems and access to all of human knowledge. 

So when I see someone that believes in God, I see a person that hasn't gone through the the process of education, scientific reasoning and logical deducting. I have a problem with them. I can never admire such a person fully, because it signifies lack of coherent thinking. My perfect person has to be an atheist.

I don't have a problem with religion per se. Many aspects of religious teachings are great. But when the supernatural part comes in, and I am asked to believe something without any proof, then I cannot stand it. It's not a matter of choice, it's just wrong. I think of such people in the same way I think of people who believe in astrology, homeopathy, or faster-than-light-travel: they are unaware of the truth and thus choose to believe in something false.

It's exactly the feeling I have towards kids that believe in Santa.

It was the church, stupid

I always wondered why modern astronomy didn't flourish in the sunny, warm climates of the Mediterranean during the renaissance and beyond.

The birth of modern astronomy was dominated by Northern Europeans: Copernicus was Polish, Brahe was Danish, Kepler, Herschel and Bessel were Germans. (Galileo in Italy is the only major exception). In addition, the prime meridian was established in Greenwich, England from all places. All these countries are notorious for the bad weather and the cloudy skies. How come it was them and not their sunnier southern counterparts?

One might argue it was because they were more advanced societies. That might explain the lack of innovation coming from Greece or Turkey, but not from Italy which was leading the renaissance at the time.

Another argument might be that only superpowers with trading activity over sea had motivation to push astronomy forward in order to ensure their dominance in the sea through accurate journeys. That might explain the case for England, but doesn't explain the German dominance, or why Portugal and Spain never developed great astronomers.

And then it dawned on me: it was the church!

The dominance of the catholic church in Rome, and the overwhelming spread of Christianity over the Mediterranean prevented people from innovating in the matters of the skies, as that was supposed to be an untouchable subject determined by God. Innovation did happen in \Italy and Spain but it focused in other, more earthly subject like engineering and mathematics. But for explaining the skies, introducing the heliocentric system, observing the motions of the stars, the church dogma didn't leave much room for thought. Just look at what happened to Galileo, the only one who dared to go against the church.

And that's how the playing field became empty for the Northern Europeans.

Τι γιορτάζω τα Νευτούγεννα

Τις γιορτές αυτές, όπως και κάθε χρόνο, ο περισσότερος χρόνος γιορτάζει τη γέννηση μιας πλασματικής θεότητας (όπου η ημερομηνία γέννησης μεταφέρθηκε τεχνητά από την Άνοιξη στις 25 Δεκεμβρίου για να συμπίπτει με τις Ρωμαϊκές γιορτές του φωτός που παραδοσιακά γινόντουσαν γύρω από το χειμερινό ηλιοστάσιο).

Εγώ προτιμώ να γιορτάζω τη γέννηση του Νεύτωνα, ακριβώς στις 25 Δεκεμβρίου 1642. Θα αναφερθώ σε ένα απλό παράδειγμα, όταν συνειδητοποίησε ότι ο νόμος της παγκόσμιας έλξης ισχύει όχι μόνο για τα ουράνια σώματα αλλά και τα αντικείμενα στη γη (όπως ένα μήλο).

[photo credit: Wikipedia]

Είμαστε στην εποχή όπου ο Νεύτωνας ήξερε τους νόμους του Κέπλερ οι οποίοι περιγράφουν την κίνηση των πλανητών γύρω από τον ήλιο. Είχε μάλιστα υπολογίσει τι είδους δύναμη χρειάζεται ώστε οι πλανήτες να ακολουθούν τις τροχιές που είχε ορίσει ο Κέπλερ: έπρεπε να είναι μια δύναμη αντιστρόφως ανάλογη με το τετράγωνο της απόστασης, δηλαδή κάθε φορά που διπλασιάζεται η απόσταση R μεταξύ δύο σωμάτων, η δύναμη F πέφτει στο 1/4, δηλαδή ισχυέι F~1/R^2.

Αυτό που επίσης ήξερε ο Νεύτωνας ήταν ότι το φεγγάρι συνεχώς "πέφτει" (έλκεται) προς τη Γη. Αν δεν υπήρχε η Γη, το φεγγάρι θα κινούταν σε ευθεία γραμμή. Λόγω της έλξης της όμως, η Γη το τραβάει προς το μέρος της κάθε δευτερόλεπτο που περνάει, αναγκάζοντάς το να κινείται κυκλικά γύρω από αυτή.

[photo credit: Microsoft Research]

Πόσο "πέφτει" το φεγγάρι προς τη Γη κάθε δευτερόλεπτο που περνάει? Αυτό υπολογίζεται εύκολα και ήταν γνωστό στο Νεύτωνα, διότι ξέρανε πολύ καλά τότε πως η περίοδος του φεγγαριού είναι περίπου 28 μέρες (2.419.200sec), και ότι βρίσκεται σε απόσταση 384.000km από τη Γη, διαγράφοντας ένα κύκλο περιμέτρου 2*π*384.000 = 2.413.000km. Άρα κάθε δευτερόλεπτο που περνάει το φεγγάρι κινείται περίπου 1 χιλιόμετρο (= 2.413.000km/2.419.200sec ) πάνω σε αυτό τον κύκλο. Σε σχέση με την ευθεία γραμμή που θα ακολουθούσε το φεγγάρι αν δεν υπήρχε η Γη, σε ένα δευτερόλεπτο το φεγγάρι είναι περίπου 1.27 χιλιοστά πιο κοντά προς τη Γη (αυτό προκύπτει από απλή γεωμετρία).

Ο Νεύτωνας το γνώριζε αυτό το νούμερο για τα 1.27 χιλιοστά σε ένα δευτερόλεπτο. Γνώριζε επίσης ότι το προκαλεί η Γη.

Και τότε του ήρθε η σκέψη: μήπως τα αντικείμενα στη Γη πέφτουν προς αυτή για τον ίδιο λόγο? Μήπως η Γη τα έλκει όπως έλκει τα ουράνια σώματα? Μήπως ο νόμος της παγκόσμιας έλξης, οτι F~1/R^2, ισχύει και για τα μήλα?

Και τότε έκανε τον εξής υπολογισμό: αφού η επιφάνεια της Γης (η οποία έχει ακτίνα περίπου 6.400km) είναι περίπου 60 φορές πιο κοντά στο κέντρο της Γης από ότι τι φεγγάρι, πρέπει η δύναμη σε ένα μήλο που πέφτει να είναι 60^2 = 3600 φορές πιο ισχυρή. Άρα, το μήλο πρέπει να πέφτει 3.600 φορές πιο γρήγορα σε σχέση με το φεγγάρι. Και αφού σε ένα δευτερόλεπτο το φεγγάρι "πέφτει" 1.27 χιλιοστά, το μήλο θα πρέπει μέσα στο ίδιο δευτερόλεπτο να πέφτει περίπου 1.27*3600 = 4.57 μέτρα.

Και εδώ ήτανε το eureka moment του Νεύτωνα,  αφού από τα πειράματα του Γαλιλαίου ο οποίος έριχνε αντικείμενα από τον πύργο της Πίζας, ήξερε ότι όντως τόσο γρήγορα πέφτουν τα μήλα στο έδαφος (και όλα τα αντικείμενα μάλιστα ανεξαρτήτως μάζας). Είναι ο απλός τύπος x=1/2*g*t^2, και ένα πείραμα που μπορεί ο καθένας μας να το επαληθεύσει.

Αυτό ήτανε το πρώτο κομβικό σημείο στην ιστορία της μοντέρνας επιστήμης, καθώς με αυτόν τον απλό υπολογισμό ξαφνικά ενοποιήθηκε η θεωρία που εξηγούσε την κίνηση των ουρανίων σωμάτων με τη θεωρία που εξηγούσε την κίνηση των επίγειων σωμάτων. Ήταν η στιγμή όπου ο Νεύτωνας κατάλαβε ότι η θεωρία του της παγκόσμιας έλξης, μάλλον ήταν σωστή.

Αυτό ήταν ένα από τα πιο εντυπωσιακά αποτελέσματα της ιστορίας της επιστήμης, γιατί φαινόταν πραγματικά παράλογο οι ίδιοι νόμοι που διέπουν την κίνηση των πλανητών να διέπουν και την κίνηση των αντικειμένων εδώ στη Γη - όταν φαινομενικά πρόκειται για τόσο διαφορετικούς κόσμους. Και όμως, με αυτόν τον απλό υπολογισμό, φανερώθηκε η αλήθεια.

Καλά Νευτούγεννα!

Nature vs. Nurture

I returned to Greece after a 7-year absence a little under a year ago. Since then, a question has been stuck into my head: what determines us as persons? Is it the genes, the environment, or both? Do we have some choice into what we choose to do in our lives?

The question popped into my head, having lived and worked in three different countries by now (Greece, United States, United Kingdom). Each of these 3 lives has felt independent from the other ones – different people, different jobs, and different environment. In each country I had different hobbies, each time discovering something new about myself.

In Greece (between 1998-2003) I discovered that I liked math and science, that I liked going to the movies, and that I needed love in my life. In the US (between 2003-2008) I discovered that I liked custom-build PCs, Richard Feynman, ethnic restaurants, travel, convertible cars, steakhouses and photography. In the UK (between 2008-2010) I further discovered that I liked spending time browsing in huge bookstores, having friends in the neighborhood to hang out with, and so on. Each time, with each new discovery, I was wondering whether these characteristics of my personality where innate or where imposed to me by the environment.

Then I joined the army in Greece for my 9-month obligatory military service. I started getting to know a large number of people from all walks of life, from 19 year old “kids” who haven’t even finished high school, to academics and people that have been working many years in the industry. At the same time, there were still in my mind the hundreds of people I have met abroad, observing how people from similar background behave in different environments. I kept wondering then: what is it, after all, that determines their personalities?

To look for the answers I decided to read Matt Ridley’s “Nature via Nurture”, where he examines exactly this question using modern science. It’s an amazing book, which summarizes beautifully the whole story, and helped me a lot in my quest.

The rest of the article provides some answers to the questions of Nature vs. Nurture. If you want a short answer (not recommending it), here it is: both the environment as well as our genes determine our personality, not in a deterministic way bur rather in a circular manner, strengthening each other rather than competing with each other. Within a certain society, genes matter most; between societies, the environment does.

The rest of the essay is longer than this simple answer, because not only do I need to explain the details of how the system works, but also to focus on the all-important question: which choices determine our lives most?

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Nature and Nurture. Genes and the environment. I first need to quickly go over the basics.

Genes are the genetic information we carry inside our cells from earlier generations, in the form of the DNA molecule. Environment is any outside influence, such as family, friends, climate, society, country status, etc.

Then there is the notion of instincts. There are actions that we do independent of our environment, such as the need for water, the search for food, or sexual desires. What makes us human and distinguishes us from animals are the things we do beyond our instincts. Culture could very well be the opposite of instincts, encompassing notions such as art, music, cooking, civilization, language, etc.

My quest began from two simple observations about the Greeks. First, Greeks eat a lot of meat (2^nd in the EU after Germany). I’ve never met a single vegetarian Greek living in Greece. Second, although I’ve met many atheists, in their vast majority Greeks are of Christian Orthodox religion. I wondered why.

The answer seems obvious here. It’s the environment! These properties (religion, food preferences) are determined via nurture and not via nature. Greeks just happen to grow up in an environment that already encourages eating lots of meat and where most people are already Christians. Had they been born in, say, an Islamic country, they would probably not eat as much meat (definitely not pork, which is the main ingredient in our souvlaki), and would also probably be Muslims. This is confirmed by Greeks that I know, who have been raised outside Greece – their food and religious preferences match each country’s own accepted norm. I myself started eating less meat and fully became an atheist as soon as I moved out of Greece.

As a second example, think of Chinese born in China versus Americans born Chinese. They all have similar genes, yet the result is completely different body types, food habits and cultural interests.

Thus I conclude that these people have not freely chosen these habits, they’ve rather just copied their environment. This is also why I have utmost respect for people who convert to being vegetarians and atheists, since they have willingly chosen their way of life by breaking free from the norms of western societies. These are the truly free. (Not that none of the rest are free – you just have to go through a process of consciously choosing your own preference rather than simply accept it).

These are just a couple of examples where nurture affects our choices. For the Greeks, there are a number of other items which, although they seem like conscious choices, are imposed from the environment: e.g. owing a small or midsize car (streets are narrow and salaries low), working as a state employee (better benefits compared to most private companies), or living in apartments (cities are too cramped to build houses). These are all pseudo-choices because they are imposed from the environment, sometimes due to being almost the only feasible options available.

What, then, is the role of genes in our life choices?

Richard Dawkins offers a great example for the role of genes. He says that genes are like recipe instructions, which, after baking, can make a great cake (that’s us). But looking at the final product (the cake), we cannot trace a specific section of the cake back to a specific word in the recipe. And the oven we bake the cake in is the effect of the environment. Similarly, our human genes are just instructions, and it’s rarely possible to trace a specific part of our body (or personality) back to a single gene.

Following this line of arguments we can also explain why we are so different from chimps although we share 98% of the same genes. Ridley suggests it’s like comparing two books; say Dan Brown’s “Angels & Demons” and Michael Herzfeld’s “Evicted from Eternity”. Both books talk about Rome, and they probably use like 90% of the same English words in them. Yet the outcome couldn’t be more different, the former book being a fictional novel and the latter a factual piece of writing. It’s the order and structure of the words that makes all the difference, not the words themselves. Same goes for genes: it’s their order and what they do that make the differences between people and species, not their explicit content.

As we shall see in a minute, these genes can be switched on and off by other genes or by the environment. This is how new properties, new personalities, and new habits can be accomplished via a fixed number of genes – not by introducing new genes, but by manipulating existing genes. And all this doesn’t need to be encoded in the genes only: the genes can be actively manipulated by nurture.

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The following sentence is the most important in the whole essay:

Nature prevails over nurture in defining personality differences within the same society.

Let me explain. This means that within the same society (i.e. having more or less a constant environment), any differences between people can be attributed to the differences in their genes.

This is backed up by evidence acquired by studying twins (which have almost identical genes) in western societies. As you probably know, identical twins originate from the same egg (thus sharing almost the same genes), while fraternal twins originate from two different eggs in the womb (this is just like normal brothers, only born at the same time). The studies show that identical twins raised apart are much more similar to each other than fraternal twins raised apart. This is true both for personality as well as for more easily measured things like body weight.

Focusing on body weight, within the same family (i.e. keeping nurture constant) identical twins have 80% correlation in weight, while fraternal twins only have 43% correlation; the genes make all the difference. When the identical twins are raised apart (i.e. varying their nurture slightly), their correlation drops just to 73% from 80%, remaining essentially unchanged. Thus genes seem to matter more than family!

This correlation holds true as long as the environment does not dramatically change. If you are an orphan in Sudan, or a worker in the slums of India, it doesn’t matter what your genetic predisposition is – it is very likely that your body weight will be low, since the access to food might be scarce. In the identical twin studies, where twins are raised apart but in more or less the same society with same access to food, the remaining differences are bound to be genetic.

In a sense, family (via nurture) is then like vitamin C – lack of it makes you ill, but above a certain level it doesn’t cause any notable differences. For the parents that they want to shape their children’s personalities, the news is then mixed. Being a parent still matters, because you have to provide a certain level of quality of life to your kids, satisfying their basic needs (food, play, education, etc.). But after these needs are met, genes matter more: nature takes over from nurture.

Another great example for the effect of family comes from examining families with criminal parents. The fact is that criminal parents give birth to children that have statistically more chances to grow up and also become criminals. Is this because of specific genes? No! It’s just that some types of personalities are more likely to get in trouble, and these personalities are heritable. Supporting this argument, studies show that adopted children in criminal families do not become criminals at the same rate as biological children.

Let’s now examine schools. For a number of reasons, kids that attend a certain school are usually of similar financial background, same race, and same location. They also receive the same education. Hence, in most schools any differences in student scores can easily be attributed to their genes. Once again, the environment determines your average status, while the genes highlight the differences between individuals.

The more meritocratic a society is the more genes matter. In an ideal meritocracy, the people with the “best” genes would attend the top schools and would therefore land the top positions, since we do not allow any random influences from the environment. Inevitably, the stupid ones would be left behind. Would you then be willing to live in a society knowing that if you are born stupid (which you can’t control really), then you are doomed to fail because you won’t be given any chances?

What about intelligence? Intelligence has also been measured in various studies, through IQ tests in various socio-economic groups. It turns out that nurture can actively affect your IQ: people that have grown up in poor families, where the parents make e.g. $4K a year, have lower IQ scores than people from families where the parents make $40K a year. Interestingly, the latter score does not increase when comparing people from families that parents make $400K a year. Once again, nurture sets the average, and once a certain average is met, any further differences are due to nature.

But all is not over once nature takes over. Nature needs nurture to express itself. Say a boy has a natural talent, such as being good at football. He needs to be provided with the corresponding environment where he can enhance his skills through practice. Having sporty genes will make you seek athletic activities, which in turn will amplify your genetic predisposition towards football. On the contrary, another boy with more “intellectual” genes will tend to read more books, enhancing his intellectual skills and maybe suppressing his sporting skills. By the time the two boys reach adulthood, one will become a footballer and the other one a writer. But their destinies were defined by nurture acting on nature – a combination.

(Sometimes I like to compare nature and nurture with a Gaussian function, defined through its mean and standard deviation. Nurture sets the mean, while nature sets the standard deviation.)

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Another example of the correlation between nature and nurture is homosexuality, which is usually regarded as a genetic predisposition. However, a “gay” gene has never been found. Why is that?

Studies on people that have older brothers show that for each extra older brother a person has, his probability of being gay rises by 1/3. Thus it’s more likely to be gay if you are not the first to occupy your mother’s womb. At the same time, the younger siblings who have older gay brothers weigh on average 170gr less at birth. It seems like the mother is having a certain reaction after the shock of the first birth, which results in subsequent babies to weigh less at birth. Based on this argument, your chances of becoming gay are increasing not genetically but totally through nurture – the environment you are grow up inside the womb. Thus we cannot pinpoint an isolated root cause of being gay to neither nature nor nurture.

(As a side note, Ridley in his book also suggests an interesting reason on why natural selection would favor gay descendants: because childless uncles would help their brothers raise their babies.)

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We’ll now focus in one of the most interesting experiments in the history of the nature vs. nurture debate – Mineka’s monkeys and the fear of snakes from the 1980’s.

Mineka observed that monkeys are afraid of snakes, and believed that this fear is acquired by young monkeys when they are observing their parents’ reactions to them. Mineka threw snakes next to a baby monkey’s food, and allowed the baby monkey (which had never seen a snake before) to approach the food and see its reaction to the snakes. When the mother of the baby monkey was present in the scene, she quickly reacted violently to the presence of the snakes, by shouting, moving around quickly, and jumping, doing everything she could to warn her child. Indeed, the baby monkey quickly acquired the same reactions, and whenever the baby monkey saw snakes it was afraid to approach. The same results repeated even when it wasn’t the baby monkey’s parent but a stranger monkey to provide the warning instead.

However, when another monkey wasn’t present in the scene, the baby monkeys went straight to the food despite the snakes around. This showed that the fear of snakes wasn’t genetic per se, but learned via nurture, after observing someone else’s behavior.

The best part comes next. Mineka subsequently decided to see if she could induce a fear for another object, such as a flower, to the baby monkeys. She had already found that a real monkey wasn’t even necessary to provide the reactions of fear for snakes – the baby monkeys would acquire the fear of snakes even after watching a monkey reaction on a TV. So, she placed flowers next to the food, while the baby monkeys were shown reactions of fear on the TV – as if the other monkeys were warning them about the “dangerous” flowers. Surprisingly, the baby monkeys never acquired any fear of flowers though!

The latter experiment indicates that there is after all a genetic role in the fear of snakes, which is turned on via nurture – by acquiring the fear from the peers. This shows that there exist features in someone’s personality that can’t be attributed to neither nature nor nurture alone – it’s only their combination that has an effect.

In fact, it is interesting to notice that we as humans also have innate fears that we have been passed down in our genes from earlier generations. We are afraid of snakes, spiders, darkness, heights, deep waters, and thunder. These are all things that could kill you in the Stone Age, so it makes sense that any of our ancestors that survived them would have developed a fear about them – which would be passed on via their genes to protect the future generations. In contrast, we are not innately afraid today of many things that can kill us, such as cars, guns or electric sockets: these phobias are modern and we haven’t had enough time to incorporate them into our genes.

Thus an interesting way to view our genes is that they contain extracted information from the environments of our ancestors. We have experiences from our present environment every day as humans, and genes provide us with information about past environments via the genetic code, transforming our bodies and our personalities, in order to be better prepared to survive in our world.

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So where does this leave us in the nature vs. nurture debate?

Well, there is no simple answer. First, the idea that single genes are responsible for single features of one’s personality is rarely true. It’s not the genes per se, but their order and combinations which matter most. And they can be affected either by nature and/or by nurture.

Second, nurture sets the stage upon which nature can play. Nurture matters most up until the basic human needs are met. But within a settled society, where the environment is more or less the same between people, the differences that arise originate mostly from nature.

Thus it seems to me that the only way we can have some serious control over our personality is by drastically changing the environment we live in. Trying to do the same things over and over within the same society won’t have any appreciable effect most of the time, because our genes would do most of the talking. People need to dramatically change environments, either by switching lifestyles, switching jobs (but totally different jobs), switching cities, or switching countries. And the more different those environments are, the more one would develop his or her personality: the nurture differences would result in affecting nature, turning on and off new genes, developing new characteristics.