A long time ago in a college biology lab far, far away…a fellow student and I performed an experiment to assess how different foodstuffs were handled by the intestine. We were not studying anything new, we were just repeating a classic experiment to examine the effect of the composition of food on the speed of digestion. So we took a few groups of rats and fed them a high-carbohydrate diet or a high-fat diet. We determined how much food the rats had consumed, and we euthanized the rats at different times after ingesting the meal and measured the weight of the contents of the stomach and intestine. We found that the food mostly made up of carbohydrate emptied quickly from the stomach, and there was a small amount of it present in the intestine. However, the food made up of mostly fat emptied slowly from the stomach, but there was more of it in the intestine; so far so good.
One of our conclusions was obvious from the results, the fatty food emptied more slowly from the stomach. But in our report on the experiment we went beyond that, and also concluded that the food made up of carbohydrate was absorbed faster into the body compared to the food made up of fat. Later we were furious to find out that our experiment report received the equivalent of a “C”! When we confronted (literally) our professor, he explained that we could not make that conclusion because we had not performed an experiment specifically designed to evaluate the absorption of the food into the body. We were incredulous at this reply. “Where else could it have gone?” we enquired. The professor explained that no matter how obvious, we could not make this claim without presenting evidence. He said that, for example, we could have measured the level of certain fats and carbohydrates in the blood vessels draining the intestines and correlated that with the amount of such nutrients inside the intestine. But absent that evidence, we had made an unwarranted conclusion.
Needless to say, we were not too happy with our grade. We had worked really hard to conduct the experiment staying late in the lab preparing the diets and making all the measurements. We grudgingly accepted the professor’s argument, but still we could not shake off the idea that, at heart, the whole notion was just a stupid formalism. After all, ingested food doesn’t just disappear; it has to go somewhere. If it is not in the intestine, where else could it have possibly gone but inside the body? At the time we did not appreciate that the requirement for evidence that the professor was imposing on us, despite repeating a well-known scientific experiment and working with a well-known animal model, was meant to alert us to be cautious when performing experiments for the first time with less known systems. In fact, if we had paid attention during high school, we would have remembered a famous example of one such experiment that reached an erroneous conclusion for not following the cautious approach required by our professor.
In 1662 the chemist Jan Baptist van Helmont conducted what is considered the first quantitative experiment in biology. He took a pot and filled it with 200 pounds of soil, which he had weighed after drying it in a furnace, and planted a willow tree sapling weighing 5 pounds in the pot. For 5 years he watered the tree, and at the end of this time period the tree weighed 169 pounds. Yet when he reweighed the soil after drying it as described above, he only found a 2 ounce difference. This indicated that the entire 164 pounds of the mass of the tree could not have possibly come from the soil. Helmont concluded that the 164 pounds of wood, bark, and roots arose from water.
This conclusion at the time (1662) must have made sense. After all, from where else could all that extra mass have possibly originated? The only thing the tree seemingly received was water, thus the difference in weight could only have come from the water, right? Notice that van Helmont did not produce any evidence to support this conclusion. Much in the same way that we concluded (without evidence) that the food was absorbed because it could not have gone anywhere else, van Helmont concluded that the extra tree mass came from the water presumably because it could not come from anywhere else.
It would be 100 more years before the work of several scientists including Joseph Priestley, Jan Ingenhousz, Jean Senebier, and Nicolas-Theodore de Saussure would establish that plants take up CO2 from the atmosphere and produce oxygen under the influence of sunlight, and that the gain in weight as a plant grows is not just due to accumulation of water or its conversion into tree material, but to the fixation of CO2 into chemical compounds which make up the solid constituents of the wood, bark, and roots. Ironically, van Helmont was the first to identify a gas produced from burning plants which he called “sylvestre”, and which we now know to be CO2, but he never made the connection that plants may take up this substance from the air.
So yes, my dear old professor, you were right. Even the obvious must be supported by evidence!
Image of the van Helmont experiment by Lars Ebbersmeyer used here under an Attribution-Share Alike 4.0 International (CC BY-SA 4.0) license.
The image below is a picture of the tallest mountain in the world. Do you know which is it?
If you answered Mount Everest you are correct. This mountain is over 29,029 feet high above sea level and has a lot of name recognition. But let me ask the above question in a different way. When measured from the center of the Earth, which is the tallest mountain in the world? Or alternatively, the summit of which mountain is closest to outer space? Surprisingly the answer is not “Everest” but rather the mountain in the picture below. Do you know its name?
This is a volcano in Ecuador called Chimborazo and it is 20, 564 feet tall when measured from sea level; an altitude way below that of Everest. However, when measured from the center of the Earth, Chimborazo is 1-2 miles taller than Everest and therefore its summit is also closer to outer space. In fact, when the height of a mountain is measured in this manner, Everest is not even in the list of the 20 highest mountains!
How can this be?
We need to remember that our experience can fool us. What can be more natural than to measure the height of a mountain from sea level to its summit? And the summit of the mountain thus found to be the highest must also be the closest point in the world to outer space, right?
If we were living in a flat Earth or on a planet that does not rotate, that would indeed be the case, but the Earth is not a perfect sphere. Due to the Earth’s rotation, the land and the sea around the equator bulge outward. Someone standing at sea level on the Earth’s poles is about 13 miles closer to the center of the Earth than someone standing at sea level on the equator. Because Chimborazo is located 1 degree south of the equator, it sits on top of this bulge, whereas Everest which is 28 degrees north of the equator is closer to the Earth’s center.
Considering this, one interesting question is: what about the death zone?
The death zone is found in high mountains above an elevation of 26,000 feet above sea level. At this altitude the abundance of oxygen is only 1/3 of that found at sea level, and the bodies of most people are incapable of adapting effectively. The death zone is one of the reasons Everest is so hard to climb, and also why the route to the top in this area of the mountain is littered with the bodies of dead climbers. One would expect that if the summit of Chimborazo is closer to outer space than the summit of Everest, then it should also have a death zone. As it turns out this is not the case because the Earth’s atmosphere also bulges at the equator. As a result of this, the summit of Chimborazo is safely below the death zone and, unlike what happens in Everest, the bodies of most people can function in the thin atmosphere of the summit if allowed the time for adaptation to high altitudes.
The foregoing illustrates the effect that small differences can have on some seemingly conventional measurements when these differences are taken into account over planetary scales. In terms of distance, the 13 miles that our planet bulges around the equator represents but a tiny fraction of the 3,959 miles comprising the Earth’s radius, and yet, this is enough to make the summit of Chimborazo the highest point on our planet!
Everest from base camp
Photo credit: Rupert Taylor-Price / Foter.com / CC BY
Photo credit: apgwhite / Foter.com / CC BY-NC-ND
In the excellent 1987 docudrama, Life Story, also known as The Race for the Double Helix, which dramatizes the discovery of DNA, Dr. Rosalind Franklin played by actress Juliet Stevenson complains to her colleague Dr.Vittorio Luzzati about leaving Paris to go to London to continue her work. “Why am I leaving Paris? She asks. Vittorio replies, “My dear Rosalind, you must turn your back on thoughts of pleasure. We are the monks of science.” To which Dr. Franklin adds, “And the nuns.” Vittorio’s comment was intended as a joke, but it did frame very well the attitude that scientists have had towards scientific work. Indeed at times the all-consuming devotion of scientists for their work has been reminiscent of a monastic class of individuals who make vows to eschew Earthly delights in favor of a chance to make scientific discoveries. This devotion and its associated work ethic were transmitted from one generation of scientists to another through teaching and example.
I had a friend who, while pursuing his studies in medicine, had been accepted to carry out basic research once a week in the lab of a professor of certain renown. The first day he went to the lab he was pretty excited, and was thrilled that the professor stayed with him performing experiments until late at night. At the end of the workday the professor asked him, “At what time are you coming tomorrow?” Somewhat puzzled, my friend tried to explain that he could only come to the lab once a week. However, the professor would have none of it and insisted he come again next day. So my friend returned to the lab next day and he stayed until late again performing experiments with the professor after which the professor again asked him, “At what time are you coming tomorrow?” This went on for a week, and my friend was pretty wiped out, so he made it a point of explaining to the professor that this could not continue. He told him that not only did he have classes and patients to attend, but he also had a family. The professor was not impressed and replied, “When I was your age, I had a family, and I was in medical school too. I had to attend patients, I had to take classes; and I also had to pay my professors for teaching me”. Then he added, “I am not charging you anything. At what time are you coming tomorrow?”
These stories of sacrifice and devotion to scientific work were once very commonplace. I have known of scientists who worked so hard that they started sleeping in their labs because it made no sense to go back home at the end of the workday. I knew a scientist who one day arrived home just to find his infant daughter was speaking. He quizzed his spouse as to when this had happened, and she just replied, “While you were away in the lab.” He had missed her first words. I knew of a scientist who one day in the fall began a period of intense work and concentration in his research. He worked for months eating at his research institute’s cafeteria, and sleeping in the student lounge. After he achieved what he had set out to do, he decided to step out of the building for a change, and realized that it was spring. He had worked through winter! There were research institutes where working weekends and holidays was something that was (unofficially) “expected from you”. In these places, it was virtually impossible to have a chance at succeeding without devoting the extra time. As recently as 3 years ago, I was endorsing the application of a student to a research position, and as one of the plusses I said that if necessary he would come to work on weekends. There was a long silence on the other side of the phone, and then the person with whom I was speaking said in a sarcastic tone, “If necessary?”
The sacrifice and devotion were not restricted merely to the amount of work that you would put into it, but also to the monetary compensation you received. I had a professor who often remarked how happy he was to be doing science, and how astonished he was that he was actually getting paid to do it. This attitude was very common in the older generations of scientists. Some of these scientists were scandalized when new generations of students started arguing that they had a right to be funded. When they were students, most of these older professors had been content just to have the honor to work alongside great scientists; salary was merely an afterthought. This mentality was so prevalent that it transcended into the broader society. I know of a colleague who once received a phone call from a human resources person to provide him information regarding a position to which he had been accepted at a company. However, he considered that the pay he was offered was too low and he tried to negotiate a higher salary. The human resources person was confused by this request and quizzically asked, “Why do you want a higher pay, aren’t you a scientist?”
The above are some of the myriads of stories out there of a culture that stressed scientific work above everything. The stereotype of scientists, according to this culture, are the individuals that work 80 hours a week and are happy to be doing what they like, regardless of the amount of salary they are receiving. I once even read an advice to young scientists stating that they should not get married too early in their careers because that would destroy their creativity! However, this culture is fading, and I think this is due to the confluence of several factors.
1) Nowadays there is an excess of scientists contending for an ever dwindling set of academic positions and resources. Competition for funding is fierce, and mere hard work and devotion to science is no guarantee of having your own lab and a successful career.
2) Many sources of employment outside academia have opened up for scientists, and it has become acceptable to have non-academic careers in science. At the turn of this century for a scientist to accept a job in industry was still referred to in some venues as “selling out”. This is not true anymore. Many scientists have flocked to occupations in industry, government, and other areas where they are able to earn decent wages and have a life.
3) Science used to be a male-dominated profession. It is easy for a man to “devote his life to science” if his wife can stay home and take care of the kids. In today’s world where both spouses work, this model is not feasible anymore.
4) Finally, I think that society has grown more cynical and selfish, and this is not necessarily all bad. If young individuals are contemplating devoting the best years of their lives to a given enterprise, they are asking more and more the question: what’s in it for me?
The hallowed halls of science nowadays have fewer monks and nuns!
The image is in the public domain
In his excellent 1994 book, The Astonishing Hypothesis, the late Nobel Prize winning scientist, Francis Crick (co-discovered of the structure of DNA with James Watson), put forward a hypothesis that boggles the mind. He wrote:
“You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules.”
He claimed that this hypothesis is astonishing because it is alien to the ideas of most people. This is presumably because, when it comes to our mind, we believe that there is something special about it. Clearly the mind is more than the product of the activity of billions of cells, no? Exalted emotions such as love and compassion and empathy or belief in the divinity or free will cannot just be a byproduct of chemical reactions and electrical impulses, right? But why would that be the case? Consider an organ like the intestine. It’s made up of billions of cells that cooperate to produce digestion. Most people will agree with the notion that the intestine produces digestion. So, if we can accept that the cells that make up the intestine produce digestion, why can’t we accept that the cells that make up the brain produce the mind?
Let’s just touch on something simple, but that nevertheless goes to the very core of our notions of free will and consciousness. Consider an action such as performing the spontaneous motor task of moving a finger to push a button. In our minds we would expect that this and other such actions entail the following sequence of events in the order specified below:
1) We become aware (conscious) that we want to perform the action.
2) We perform the action.
But what goes on in our brains even before we become aware that we want to perform the action? Many people would guess: nothing. Whatever brain activity occurs associated with the action must logically occur after we become aware that we are going to perform the action. After all, how could there possibly be nerve activity associated with an action that we are not even yet aware that we want to perform?
Warning! Warning! - Insert blaring alarms and rotating red lights here - Fasten your existential seat belts because this ride is about to get bumpy!
In 1983 a team of researchers led by Dr. Benjamin Libet carried out a now famous experiment to evaluate this question. The researchers recorded the electrical activity in the brains of test subjects which were asked to perform a motor task in a spontaneous fashion, and they also asked the subjects to record the time at which they became aware that they wanted to perform the task. The surprising result of the experiment was that, while the awareness of wanting to perform the task preceded the actual task as expected, the electrical cerebral activity associated with the motor task performed by the subjects preceded by several hundred milliseconds the reported awareness of wanting to perform the task! This amazing experimental result has been replicated by other researchers employing different methodologies.
One study employing magnetic resonance to image brain activity stablished not only that the brain activity associated with the task is detected in some brain centers up to 7 seconds before the subject becomes aware of wanting to perform the action, but also that decisions based on choosing between 2 tasks could be predicted from the brain imaging information with an accuracy significantly above chance (60%). Delving even deeper into the brain, another group of researchers recorded electrical activity from hundreds of single neurons in the brains of several subjects performing tasks and found that these neurons changed their firing rate and were recruited to participate in generating actions more than one second before the subjects reported deciding to perform the action. The researchers could predict with 80% accuracy the impending decision to perform a task, and they concluded that volition emerges only after the firing rate of the assembly of neurons crosses a threshold.
The interpretations of these types of experimental results have triggered a debate that is still ongoing. The most unsettling interpretation is that there is no free will (i.e. your brain decides what you are going to do before you even become aware you want to do it). However, there are many critics that claim that there are technical flaws in the experiments, that the data is being overinterpreted, that the electrical activity detected is merely preparative with no significant information about the task, or that it is a stretch to extrapolate from a simple motor task to other decisions we make that are orders of magnitude more complex. In any case the question of whether free will exists is in my opinion irrelevant because our society cannot function under the premise that it doesn’t. What interests me from the point of view of the astounding hypothesis, is the possibility that the awareness of wanting to perform an action before we perform it is merely an illusion created by the brain.
This notion is not farfetched. As I explained in an earlier post, the brain creates internal illusions for us that we employ to interact with reality. Colors are not “real”, what is real is the wavelength of the light that hits our eyes. What we perceive as “color” is merely an internal representation of an outside reality (wavelength). The same goes for the rest of our senses. As long as there is a correspondence between reality and what is perceived, what is perceived does not have to be a true (veridical) representation of said reality. Consider your computer screen. It allows you to create files, edit them, move them around, save them or delete them. However, the true physical (veridical) representation of what goes on in the computer hard drive when you work with files is nowhere near what you see on your screen. This is so much so, that some IT professionals refer to the computer screen as the “user illusion”.
So, much in the same way that the brain creates useful illusions like colors that allow us to interact with the reality that light has wavelengths, or the computer geeks create user illusions (file icons) that allow us to interact with the hard drive, could it be that the awareness of wanting to perform actions, in other words, becoming conscious of wanting to do something, is just merely an illusion that the brain creates for the mind to operate efficiently?
We are still in the infancy of attempts to answer these questions, but what is undeniable is that the evidence indicates that there is substantial brain activity taking place before we perform actions that we are not even yet aware we wish to perform, and that this brain activity contains a certain degree of information regarding the nature of these actions. As our brain imaging technology and our capacity to analyze the data gets better, will we be able to predict with certainty what decision a person will make just by examining their brain activity before they become aware they want to make the decision?
It’s too early to tell, but from my vantage point it seems that so far Crick’s astonishing hypothesis is looking more and more plausible.
The image of the cover of the book The Astonishing Hypothesis is copyrighted and used here under the legal doctrine of Fair Use. The Free Will image by Nick Youngson is used here under an Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) license.