When people say or write things like “nothing is impossible”, they normally mean this as a motivational slogan intended to overcome life’s difficulties. They don’t literally believe that nothing is impossible, but rather that talent, focus, hard work, and dedication can overcome seemingly insurmountable obstacles to achieve success. And you know what? I’m fine with that. It may not be accurate, but I understand that people may need a little oomph in their lives. If some accuracy needs to be sacrificed to help people succeed, I am willing to look the other way, so to speak. However, some people actually believe that the maxim “nothing is impossible” is true, and not only in the realm of personal achievements, but also in the field of science. I have had a few discussions with these mystics that left me wishing that I had applied Alder’s Razor. I have tried to explain that our world functions based on a set of rules that clearly delineate what is and what isn’t possible, and that science is in the business of finding what these rules are. In response to this, I normally get a list of things that scientist thought to be impossible that were later demonstrated to be possible, along with comments like “scientific theories have been proven false again and again” and some interspersed subtle and not so subtle hints that my mind is not sufficiently open.
To these criticisms, I answer that science sometimes moves forward by trial and error, and, like these critics point out, scientists have made mistakes or have underestimated the complexity of the phenomena they were studying. But, as more knowledge was generated and explanations were refined, sufficiently developed scientific theories were established that allowed accurate discrimination of the possible from the impossible. Additionally, I have already pointed out not only that the vast majority of scientific theories have not been proven false, but that there are dangers in keeping your mind too open.
Nevertheless, the more important point, that seems to be ignored by the “nothing is impossible” crowd, is that our very lives depend on knowing what is possible and impossible in the world around us. Think about it. When we walk on a cement surface, we know that it will not suddenly turn into quicksand and swallow us up. When we approach a tree, we know it will not suddenly uproot itself and attack us. When a cloud passes over us, we know it will not suddenly turn to lead, fall, and crush us. We have a very clear understanding of how cement surfaces, trees, clouds, and myriads of other things work, and we know with absolute certainty what they can and cannot do. We know what can and cannot happen. We know what is possible and what is impossible. If this understanding of how our world works were false, our lives would be in peril. But our capacity to gain this understanding is nothing new or even limited to the human species.
In nature we observe that animals also gain an understanding of how their surroundings work through individual experience and from observing other animals. They develop an understanding of what is edible and what isn’t, of what prey is safe to attack and what prey is dangerous, of what places are safe to be in and which are not, and so on. There is a rhyme and reason to this understanding that animals gain. They grasp that certain things are possible and other not, and they exploit this knowledge to negotiate the complexity of their environments and survive.
The animal ancestors of humans acquired this information like other animals through their individual experience and from observing others. However, as ancient humans developed the capacity to think and communicate to an extent that was orders of magnitude higher than that of their animal kin, the knowledge they derived from experience became insufficient. There were many scary things happening in the world that they did not understand and could not control like earthquakes, storms, volcanoes, droughts, pests, and disease that could dramatically affect their lives. And there were also other things like eclipses, comets, shooting stars, or the moon acquiring a red hue that were mysterious. Ancient humans were able to formulate questions. Why did these things happen? Was there something or someone making them happen? How can I prevent bad things from happening? How can I be spared? Ignorance and fear begat superstition and the belief in the supernatural in order to allow humans to make sense of their surroundings and gain a measure of control over their existence.
But then some humans started investigating how the world around them worked. They observed. They experimented. They found regularities and patterns. They asked and answered questions and made predictions based on the answers, which they then refined from experience. Science was born. And science was able to deliver explanations regarding the nature and inner workings of those scary things and those mysterious things allowing us to understand them, and in many cases control them, or at least reduce their detrimental effects on our lives. Viewed from this vantage point, science is just merely a more effective way of obtaining the information that we once obtained through experience.
Knowledge of what is possible and not possible is key to our survival, and science has been the most successful way in which we gave gained this information. To those who say “nothing is impossible” I just have one word: balderdash!
Image from Pixabay is free for commercial use (Creative Commons CC0)
The scientific consensus has been getting a bad rap lately. Some people argue that whether science is right or not about an issue is not decided by majority vote. Rather, it is claimed, it only takes one scientist to be right to decide whether the science regarding an issue is true or not. Those that make this argument then go on to provide a list of scientists that went against the consensus and prevailed. The people making these argument then proudly proclaim that in science there is no such thing as consensus, that science does not require a consensus, and if there is a consensus, then it isn’t science!
Let’s try to understand a few things about the scientific consensus.
A scientific consensus is not reached when scientists get together and “vote”. A scientific consensus, unlike the use of this word in other fields such as politics, does not involve a compromise. Also the word consensus is sometimes used to denote the current state of a field as in “the current consensus”. In a new field of study the term “scientific consensus” really means “the current opinion” and it is understood that such opinion is very likely to be overturned in the future. This is not the meaning of consensus that better serves science in the public sphere when dealing with topics like climate change or evolution. The meaning of scientific consensus that we should seek is that consensus attained in a field of science that is backed by a fully developed scientific theory. A field of science that has not generated a fully developed scientific theory is incapable of generating a true scientific consensus. The reason this is the case is because a fully developed scientific theory has grasped important aspects of reality in its formulation and is likely to have a high degree of completeness.
How is such a theory developed?
When a field of study is in its early stages, scientists from several countries, ethnic backgrounds, beliefs, political persuasions, etc. begin tackling a problem. All these scientists bring their intellect and life experience to bear on answering the questions being investigated. Initially there is a multiplicity of possible answers, there are uncertainties, deficiencies and limitations in the methodologies, and there is confusion. Many scientists go down blind alleys only to find they have wasted their time on a wrong approach and have to turn back. Some explanations emerge that seem to be better than others. Methodologies are improved. Hypotheses are refined. Exceptions are explained. Scientists from other areas enter the field and bring new tools and ideas (a very important development). The research performed in these other fields is found to be complementary to the research in the emerging field. Eventually as the field matures scientists from different laboratories using different methodologies begin obtaining the same results and elaborate models that they use to make predictions (another very important development). Some predictions are not fulfilled and the models that generated them fall by the wayside and are replaced by new models that are more accurate at explaining the data and making new predictions. Eventually the field coalesces around a theory. The theory is used to generate practical applications and to explain observations in other areas of science.
A theory developed through the process described above is not an ephemeral construct that can be overturned at any time. The very technology that we use in our everyday lives depends on hundreds of solid scientific theories that have never been disproven. Many people who do not understand the nature of scientific truth confuse the overturning of a scientific theory with its refinement. This is because there is the erroneous notion that scientific theories should explain everything, and this is not the case. A scientific theory only has to answer the most important questions raised by scientists.
Thus, when a fully developed scientific theory is produced in a field of study this means that scientists have stopped arguing with each other about the salient points addressed by the theory. In other words, they have reached a consensus. This is the true meaning of a scientific consensus. Of course, the fact that there is a consensus doesn’t mean that everything has been settled. Scientists that agree with evolution are still debating how evolution happens. Scientists that agree with climate change are still debating its extent and mechanisms. Nevertheless, a consensus does mean that the major overreaching question in the field has been answered to the satisfaction of the vast majority of the scientists involved in the research.
The consensus can, in principle, be modified if the underlying theory that backs the consensus is found to be incomplete, but this is only true if the refinements to the theory in the form of new observations, new data, or new interpretations of old data or old observations, significantly modify those parts of the theory that are vital for the consensus. In the case of a fully developed scientific theory this is no easy task, and the burden of proof is on those who seek to modify the theory. Some people claim that this promotes a herd mentality that leads to dissenting scientists being penalized and those that are compliant being rewarded resulting in the discouragement of innovation. However, what has to be understood is that science is a very conservative enterprise that sets a very high bar for those seeking to challenge what is considered established knowledge. If you are going against the prevailing theory, you’d better have very good evidence. This is not the product of a herd mentality or a way to discourage innovation: it is a way of protecting established science against error.
In the public debate, when you hear that a consensus has been reached in a particular field of science, you need to ask about the nature of the underlying theory that backs it. If the theory fulfils the requirements of a fully developed scientific theory, then the consensus is good. A consensus is only as good as the theory that supports it. However, suggesting that there is no such thing as a scientific consensus or that it is irrelevant is nothing more than a strategy to delegitimize science. It has been used in the past by entities such as the cigarette lobby, and it is being used today by creationists, climate change deniers, and other groups that seek to further their anti-science agendas.
Image by Nick Youngson used here under an Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) license.
Some scientific theories that are in the way of religious, political, and corporate interests have been getting a bad rap. These theories are claimed to be false by their foes. So for example, creationist claim that evolution is false, climate change deniers claim that global warming is false, and so on. In fact, many people seem to imply that theories are ephemeral, and to buttress their claim they offer a list of theories that have been proven “false”. Why should we rely on a scientific theory to affect public policy today if it can be shown to be false tomorrow?
In addressing this issue there are several things we have to consider.
Before we begin, we need to make the clarification that the word “theory” in the popular parlance can be a synonym for a guess or a very preliminary explanation. In science, a theory is a vastly more stable form of knowledge. In fact, if the theory is sufficiently developed, it in itself can become a fact. So what are the characteristics of a sufficiently developed theory? They are:
1) It explains the existing observations and experimental results.
2) It has generated predictions that have been found to be true.
3) It has generated practical applications that work.
4) Results from other scientific disciplines corroborate the theory and the theory corroborates results in other scientific disciplines.
Please read the list above again carefully. Don’t you think that when a theory fulfils these characteristics we can say with confidence that it has clearly grasped important aspects of the realities it’s trying to explain? But, you may ask, what if a genius like an Einstein comes along and thinks up a new interpretation for everything the theory explains and predicts, and expands it into a different theory to explain new things? Can’t we say then the theory was proven false?
Well, let’s consider what Einstein did. He reinterpreted Newton’s laws of gravitation and motion, and came up with explanations for phenomena the Newtonian interpretations could not explain. Einstein thus relegated Newton’s laws to particular cases where velocities are much lower than that of the speed of light or when very strong gravitational fields are not involved. But here is the thing: the speeds at which planets, rockets, space probes, and objects in everyday life move, and their behavior in the gravitational fields that they encounter most of the time, can be described with a satisfactory level of accuracy by Newton’s laws. The existence of a planet (Neptune) and the return of a comet (Halley’s Comet) were predicted using Newton’s laws. The life of astronauts and the integrity of multimillion dollar space probes depend on the veracity of the calculations employing Newton’s Laws. Is it fair to say that Einstein proved Newton’s theories were false?
Of course not! Einstein showed Newton’s theories were incomplete, and this is what the public has to understand when discussing scientific theories. Sufficiently developed scientific theories cannot be false, they can only be incomplete. When assessing scientific theories, it is counterproductive to talk in terms of true or false. What has to be discussed is whether a theory has been formulated at a high enough level of detail, in other words, whether the theory is complete enough. We don’t need theories to be 100% true. They can’t be (nothing can), and they don’t have to be. We only need the theory to be complete enough to be useful for society.
Finally, it must be pointed out that the vast majority of scientific theories are not “big name” theories such as the theory of evolution or global warming. There are hundreds of scientific fields and subfields that have given rise to thousands of theories most of which are boring, highly technical, and devoid of importance to the “culture wars”. Therefore they do not make the news, and non-scientists are not even aware of them. Most of these theories have never been overturned, and in fact form the basis of modern science leading to tens of thousands of practical applications and policies. If these theories were not sufficiently complete representations of reality, modern life would not be possible!
So next time you are pondering the worthiness of a scientific theory, remember, it's all in the completeness.
The figure is a collage of a copy of a painting of Isaac Newton by Sir Godfrey Kneller (1689), which is in the public domain, and a photograph of Albert Einstein by Orren Jack Turner obtained from the Library of Congress, which is also in the public domain because it was published in the United States between 1923 and 1963 and the copyright was not renewed.