The best antidote for pseudoscience, I firmly believe, is science.
Carl Sagan, Broca’s Brain
Nullius in verba (Latin for “on the word of no one”) the motto of the Royal Society, is taken to mean ‘take nobody’s word for it’. It is an expression of the determination to withstand the domination of authority and to verify all statements by an appeal to facts.
One of the most influential voices in the antivaccine movement is Andrew Wakefield, who together with other collaborators, in 1998, published a study in the prestigious medical journal The Lancet, claiming that the measles, mumps, and rubella (MMR) vaccine predisposed children to neurological conditions, including autism. However, other researchers were unable to reproduce his findings. Most of Wakefield’s co-authors later withdrew their support for the study’s interpretations. Despite this, Wakefield has continued to defend his research and conclusions.
So, if a leading publication can publish information that is later debunked, how are we meant to sift through it? How can we tell what science is, and what pseudoscience is?
Pseudoscience is a complex, influential phenomenon in society, which can have negative, and even deadly consequences for the population. In principle, it should be easy to distinguish real science from crackpottery, such as injecting disinfectant to kill a virus, as then President Trump once recommended. But as we also saw in Idea 11, millions of people inhabit their own reality bubble. In other words, a big chunk of the population has been hijacked by misinformation.
The cases of Wakefield and many others show that even scientists have difficulty distinguishing science from pseudoscience. In fact, pseudoscience proliferates in academia, and it is not always easy to determine whether a discipline is scientific or not. It is crucial to adopt a critical attitude given what is at stake – but how exactly do we do that? As I argue below, it requires an understanding of the nature and limits of science, of logical fallacies, of the psychology of belief, and even of politics and sociology.
Science vs nonscience: How to tell the difference?
How can we tell then when something is scientific or not? This is known in the philosophy of science as the demarcation problem, an expression first used by the Austrian philosopher Karl Popper. He held that to demarcate science from pseudoscience it is necessary to determine whether a theory is falsifiable, that is refutable or testable. Thus, a theory is falsifiable only if it can be refuted by experience. Theories that cannot be refuted by counterexamples are untestable (or unfalsifiable, or irrefutable). Popper also considered that some theories are unfalsifiable by means of introducing new ad hoc reinterpretations or excuses to escape refutation.[1]
Popper considered that the Marxist theory of history and psychoanalysis are not refutable, therefore unscientific. The former is based on the view that history is governed by universal laws and that according to these laws, a society moves through a series of stages, with the transition between stages being driven by class struggle. The latter is a system of psychological theory and therapy, which aims to treat mental disorders by investigating the interaction of conscious and unconscious elements in the mind, and bringing repressed fears and conflicts into the conscious mind by techniques such as dream interpretation and free association.
Unquestionably, these theories have had historical and cultural relevance. The Marxist theory of history has had an enormous influence on historiography and is still influential within the area of social history. It provided the first sustained efforts at social history and most non-Marxist historians make use of tools developed within Marxist historiography, like dialectical analysis of social formations, class analysis, or the project of broadening the scope of history into social history. Similarly, psychoanalysis is part not only of the history of psychology, but also of the history of human culture. Freud’s ideas have been highly influential in psychology.[2]
However, according to Popper, the main problem with these theories is that they are too broad and too flexible with respect to observations to say anything interesting. In effect, with a little imagination, every historical event can be recast as an economic power struggle between classes, and every psychological observation can be interpreted as an unconscious or repressed obsession with sex. That is, by “explaining” everything the theories end up explaining nothing.
Box 12: Hypothesis and Proof in Science One of the reasons why philosophers admire science is because of the cautious, provisional, and even skeptical methods employed by the best scientists. Karl Popper went so far as to claim that the best a scientist can do is to refute or falsify a hypothesis (see main text). He elevated the process of attempted refutation – falsifiability – to the basis of all genuinely scientific methodology. It is now clear that there is no clean way of separating scientific from nonscientific claims just by applying “simple” principles like falsifiability. Science is too complicated for that as the examples discussed in the main text show. Still, a theory could accumulate enough evidence to make it almost impossible to reject its claims. For instance, the proposition that matter and energy are equivalent and linked by Einstein’s equation E=mc2 is no longer considered a theory but a fact. We have the atomic bomb and nuclear power to prove it. More recently, researchers using extremely sensitive instruments based on quantum effects have verified that E does indeed equal mc2 to better than 1 part in 2 million. There is also evidence that energy can be converted back into matter as has been shown routinely by the operation of large particle colliders. More advanced theories in the future may refine Einstein’s equations to a finer degree, in the same way that his theories are a refinement of Newton’s ideas on gravitation. While such a refinement may establish more subtle, second or third order relationships between matter and energy, the equivalence is well established. Consider also Darwinian evolution, which Popper claimed was unscientific. The accumulated, interlinked evidence in support of evolution is so vast that biologists consider it a fact and a theory at the same time. That is, biologists admit that there is uncertainty regarding the mechanisms and implications of evolution, not the fact that evolution has occurred in the species. Darwin himself emphasized the difference between his two greatest achievements: establishing the fact of evolution and proposing a theory – natural selection – to explain the mechanism of evolution. The fossil record and abundant other evidence in diverse areas such as anatomy, epidemiology and genetics testify that organisms have evolved through time. Although no one observed those transformations, the indirect evidence is clear, unambiguous, and compelling (see Idea 2). All sciences frequently rely on indirect evidence. Physicists cannot see subatomic particles directly, for instance, so they verify their existence by watching for telltale tracks that the particles leave in cloud chambers. The absence of direct observation does not make physicists’ conclusions less certain. Trying to undermine evolution is not unlike trying to undermine the atomic theory of matter (see Idea 1).
Popper also thought that that no amount of data can really prove a theory, but that even a single key data point can potentially falsify it. In this view, science makes progress not by proving its theories right, an impossibility according to Popper, but by eliminating an increasing number of wrong theories. Thus, pseudoscience cannot make progress because its theories are so flexible that they can accommodate any observation whatsoever.
Nowadays, most scientists consider the demarcation ideas of Popper, who died in 1994, as a good guideline, but which cannot be taken at face value and applied indiscriminately to every scientific paradigm or field. For instance, falsification is almost irrelevant to many chemists whose main activity is to synthesize molecules. As stated by one chemist, “What hypothesis are you falsifying, exactly, when you are making a new drug to treat cancer or a new polymer to sense toxic environmental chemicals? Now you could get very vague and general and claim that every scientific experiment is a falsification experiment since it's implicitly based on belief in some principle of science. But as they say, a theory that explains everything explains nothing, so such a catchall definition of falsification ceases to be useful.”[3]
In practice, a large amount of data does improve confidence in a theory (see Box 12). Scientists usually do not need to confirm a theory 100 percent to trust and use it; in most cases a theory only needs to be good enough. Most scientists do not discard a theory the moment there is an experiment which disagrees with its main conclusions. Maybe the apparatus is flawed, or maybe the statistics are not done or interpreted correctly. Most frequently, however, it is a simple tweaking of the theory that can save it.
Consider, for instance, a groundbreaking result that seemed to invalidate the whole field of particle physics. In 1964, an experiment by American physicists showed a violation of CP-symmetry, which states that the laws of physics should be the same if a particle is interchanged with its antiparticle (C-symmetry) while its spatial coordinates are inverted (P-symmetry). Stated in layman terms, it means that left and right and up and down are indistinguishable in the sense that an atomic nucleus emits decay products up as often as down and left as often as right.
However, the highly unexpected discovery of CP violation did not require physicists to abandon the theoretical framework of particle physics. Instead, they introduced some further principles that accounted for the anomalous phenomenon. Moreover, the violation of CP symmetry enabled physicists to make an absolute distinction between matter and antimatter, which may have profound implications for cosmology (see Idea 1).[4]
Another reason why falsification is considered too rigid a criterion to separate science from nonscience is because much of modern science is based on models rather than theories. Models are both simpler and less rigorous than theories and they apply to specific, complicated situations which cannot be resolved from first principles. As science becomes even more complex and model-driven, this failure of falsification to discriminate between competing models will become even more widespread.
Consider string theory, which I reviewed in Idea 3. The main virtue of string theory is its potential to unify general relativity with quantum mechanics since both theoretical frameworks are largely incompatible. The central assumption of string theory is that fundamental particles are not point-like particles but one-dimensional “strings,” which have the dimension of length. In this theoretical framework, strings are the basic constituents of matter. These strings can vibrate in different manners and the distinct modes of vibration produce distinct types of particles. As we saw, one of its byproducts is the idea of the multiverse, the existence of universes besides ours.
Undoubtedly, the proponents of string theory and the multiverse have greatly expanded our conception of reality and opened our minds to the possibility of other universes and dimensions. However, in the last years there has been an increasing number of skeptical remarks toward string theory. The theoretical physicist Peter Woit, for example, has deemed the theory too complex, and even “ugly” and “fake physics”.[5] The main problem, though, is that it has not produced even one testable prediction since its inception, about four decades ago. Moreover, its predictions require a huge set of assumptions that are unsupported by a lack of scientific evidence.
Still, there are many researchers who are drawn in by the mathematical allure of the theory and its promise to unify gravity and quantum theory. It continues to be an active area of research. But can string theory be called scientific? By being too flexible, the theory exhibits some of the characteristics of pseudoscience. The physicist turned philosopher Richard Dawid has proposed that string theory is redefining the way science should be understood. He argues that lack of empirical evidence should not invalidate a theory if there are three elements present: [6]
1. The trust in a theory is higher if its development is based on extending existing successful research programs.
2. The more time passes in which we fail to find a theory as successful as the one we have the more likely it is that the one theory we have found is unique and correct.
3. A finding is perceived more important if it wasn’t expected.
Dawid then argues basically that since a lot of physicists are de facto not relying on the scientific method any more maybe philosophers should face reality and come up with a better explanation that would alter the scientific method so that according to the new method the above arguments were scientific. He called this “non-empirical” science. However, this notion has been challenged by both philosophers and physicists. For instance, the astrophysicists Ellis and Silk claim, rightly I think, that non-empirical science is an oxymoron. [7]
Rethinking science: its essence and scope
In recent years there has been an effort to refine Popper’s demarcation ideas, mainly by philosophers of science. Most of them now agree that falsifiability or testability is a necessary but not a sufficient condition for a theory to be called scientific. Hypothesis and theories should also be supported by evidence at some point to achieve scientific status. Moreover, they should also be reproducible or replicable. Reproducibility is described as the capacity of different researchers to find the same (or similar) results when repeating an experiment or test.[8] Wakefield’s hypothesis that the MMR vaccine causes autism is falsifiable in principle. However, it is unsupported by evidence and researchers have been unable to reproduce the results.
The reproducibility of experiments is a crucial feature of scientific research. In 1989, the chemists Stanley Pons and Martin Fleischman announced to the press that they could achieve nuclear fusion well below the temperature required for thermonuclear reactions. This would have solved the energy problems of the world, as nuclear fusion can liberate huge amounts of energy. Unfortunately, scientists could not reproduce their experiments. This is precisely why in science, one study or claim means little, but replication provides us with a basis for greater certainty.
Yet, as we have seen, there remains quite a bit of disagreement regarding the exact criteria that demarcates or separates science from pseudoscience. One point of contention in our society is the role that religion can play in scientific inquiry. One such example is Intelligent Design, or ID. According to the proponents of ID, some organisms are too complex to be explained by evolution alone, pointing to the possibility of supernatural influences. The advocates of ID claim that it represents a scientific alternative to evolution and thus it belongs in the classrooms.
Some consider ID a full-fledged paradigm shift. “We are in the very initial stages of scientific revolution,” declared in 2005 Stephen Meyer, director of the Center for Science and Culture at the Discovery Institute, a Christian, conservative think tank. “We want to have,” he writes, “an effect on the dominant view of our culture.”[9]
The purported revolution never materialized. ID presents two main arguments against evolutionary explanations: irreducible complexity and specified complexity, asserting that certain biological and informational features of living things are too complex to be the result of natural selection. There are several problems with this claim. For starters, detailed scientific examination has rebutted several examples for which evolutionary explanations are claimed to be impossible.[10]
Furthermore, evidence against evolution does not by itself constitute evidence for design; this is what is called a false dichotomy fallacy. It could be that there is a yet unknown natural mechanism that can explain the observed changes. This also applies to claims such as miraculous curations for which supposedly there are no known medical explanations.
For all its claims of being “rigorous and evidence-based”, the proponents of ID have yet to produce a scientific theory (see discussion below). Despite this shortcoming, the intelligent design movement, supported by the Discovery Institute, advocated inclusion of ID in public school biology curricula. This led to the 2005 Kitzmiller v. Dover Area School District trial, which found that ID was not science, that it “cannot uncouple itself from its creationist, and thus religious, antecedents,” and that its promotion on public schools is unconstitutional.[11]
Despite its rejection by the scientific establishment and legal system, ID and other pseudo-sciences like homeopathy and astrology remain highly influential in our culture and society. In the absence of a consensus on clear demarcation criteria between science and pseudoscience, the philosophers of science have tried to reassess the meaning of science and reduce it to its “essence”, one that most experts in the field would agree on. The philosopher Massimo Pigliucci, a critic of pseudoscience and creationism, proposes three fundamental elements that all scientific inquiry has in common: naturalism, theory, and empiricism.[12] I review them briefly below.
Naturalism
Naturalism is simply the idea that the world works according to natural laws and processes. In other words, science deals only with natural phenomena and processes, and thus it has no business getting into supernaturalism. This does not mean that the supernatural does not exist, it only acknowledges the fact that science, our main guide to the real world, is limited to the study of natural phenomena. The philosophers refer to this as “methodological naturalism,” which differs from “philosophical naturalism,” the belief that there really is no supernatural at all. This approach allows scientists to pursue their work independently of their private religious beliefs. In fact, Georges Lemaître, one of the early conceivers of the Big Bang theory, was a Jesuit priest.
In practice, most of us are methodological naturalists. Suppose you arrive one morning at the office and find that your computer is not turning on. Most likely your first thought is not that a supernatural agent is preventing you from starting your workday. Instead, you will verify that there is not a power outage, and that the computer is connected to an outlet. If that checks out, you will proceed to ensure that there are no loose or missing cables. In other words, you are assuming – without any evidence – that there is a natural explanation for why your computer is not working. If nothing seems to work and you are desperate because you need to get started on a big project you probably will not call a priest, imam, or rabbi, but a computer expert.
Should we then keep an open mind with respect to the supernatural? In principle, yes, but, as the late physicist and science advocate par excellence Carl Sagan famously stated, extraordinary claims require extraordinary evidence. This is the case if we claim that a given phenomenon or event has supernatural causes, which presents an extremely high bar to clear. As we saw, the “evidence” presented by the advocates of ID does not really amount to a scientific theory. Likewise, proving that there is no such thing as the supernatural – God or gods, ghosts, spirits, etc. – is beyond the scope of science.
Theory
The notion of theory used by the public in general is different from its meaning in a scientific context, which can cause confusion when scientists talk about their work. In common parlance, theory is often used to refer to something that is rather speculative (think conspiracy theory). Because of this, it sometimes takes on a negative tone (for example, when creationists refer to evolution as “just a theory”). This meaning strongly contrasts with the meaning of theory as it is used in science. Consider, for example, this definition taken from the 2008 book Science, Evolution and Creationism, published by the National Academy of Sciences (p11):
The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspects of nature that is supported by a vast body of evidence. Many scientific theories are so well established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the Sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics). One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed. For example, the theory of gravitation predicted the behavior of objects on the Moon and other planets long before the activities of spacecraft and astronauts confirmed them. The evolutionary biologists who discovered Tiktaalik [(see Idea 2)] predicted that they would find fossils intermediate between fish and limbed terrestrial animals in sediments that were about 375 million years old. Their discovery confirmed the prediction made on the basis of evolutionary theory. In turn, confirmation of a prediction increases confidence in that theory.
A scientific theory is thus a carefully thought-out explanation for observations of the natural world that brings together many facts and hypotheses that can be used to make predictions. Predictions from these hypotheses are tested by experiment and further ideas or hypothesis developed. Any hypothesis cogent enough to make predictions can then be tested in this way. Thus, if by calling evolution “just a theory” creationists believe they are damaging its reputation they are barking at the wrong tree. Evolution is “just a theory” in the same way that relativity, plate tectonics, and quantum mechanics are. However, scientific development does not always follow a straight path, from observation to theory. Sometimes it takes place with a theory first being developed, and then gaining support, based on its logic and principles. The theory of general relativity, for instance, was invented, gained supporters, and only later confirmed by experiment.
Empiricism
Empiricism means that real knowledge is based on sensorial experience, not on theories and hypothesis. In other words, it is fundamental that all hypotheses and theories be tested against observations of the natural world rather than resting solely on a priori reasoning, intuition, or revelation. The way that empiricism is used by scientists means that “knowledge is based on experience” and that “knowledge is tentative and probabilistic, subject to continued revision and falsification.”[13] As we saw, empirical evidence is necessary before a theory or hypothesis is accepted by the scientific community. When we reviewed string theory, we saw that the lack of empirical evidence has convinced many scientists that, despite its potential promise to unite gravity and quantum mechanics and its mathematical sophistication, it qualifies as pseudoscience.
As Piglucci specifies, “empirical evidence … does not necessarily mean experiment, but more broadly refers to any combination of experimentation and systematic observation that produces not just fact, but data.” (p304). Therefore, evidence means not only direct observation of experimental resources, but also presenting the results in specialized journals, seminaries, and conferences, and subjecting them to the scrutiny of the scientific community; scrutiny being the key word here. It is important that experimental results are replicated by other scientists. The fact that scientists were unable to replicate results is the main reason the hypothesis that fusion can be achieved at room temperature was rejected.
Applying these three elements to a purported theory can help us determine if it meets the criteria to be called scientific. ID does not meet the first criteria of naturalism. Homeopathy is one of the most used forms of alternative medicines and it has a large global market. What makes it pseudoscience is that there is no empirical evidence to support it. Homeopathic treatments may indeed ease symptoms and have other therapeutic effects, but they are not attributable to homeopathic remedies. Effectiveness stems from the placebo effect and from human interactions between patient and therapist.[14]
It is a similar situation with astrology, which claims to discern information about human affairs and terrestrial events by studying the movements and relative positions of celestial objects. Throughout most of its history, which can be traced to at least the 2nd millennium BCE, astrology was considered a scholarly tradition and was common in academic circles. However, no scientific evidence has been found to support any of the premises or purported effects outlined in astrological traditions, and researchers have shown it to have no scientific validity or explanatory power.[15]
We also need to consider the cultural, social, and political factors that influence what qualifies as good science. In his classic book The Structure of Scientific Revolutions, Thomas Kuhn describes the process of “paradigm shift” through which new ideas and new ways of thinking replace the old. Kuhn argues that scientific advancement is not evolutionary but rather is a “series of peaceful interludes punctuated by intellectually violent revolutions,” and in those revolutions, “one conceptual world view is replaced by another.”[16] A paradigm shift changes how we view the world, including the sorts of questions that scientists consider worth asking, and even how we do science. The discovery of DNA, for instance, marked one such shift, the theory of plate tectonics another. As Kuhn describes it, paradigm shift is a process influenced as much by scientific as by social, moral, and psychological factors, including the egos of the actors involved.
To conclude: The scientific method is not perfect, but it is an effective tool when applied correctly
What we may conclude then, is that there is no clear demarcation between science and pseudoscience. There is no litmus test for whether something is “good” science or not; it depends on a variety of factors, and the role of these factors may change over time. Something that was considered fringe discipline becomes part of the scientific mainstream and, conversely, a formerly respectable field may acquire the characteristic of a pseudoscience.
Will the search for new scientific paradigms ever end in a final theory? Some scholars believe that the most fundamental truth about nature is simply beyond the human intellect, the way that quantum mechanics is beyond the intellect of a monkey. Thomas Kuhn himself was against the idea of scientific progress, in the sense that science brings us closer to an accurate description of the world. He thought that in science, truth is an optional and gratuitous concept. On his part, Karl Popper believed that there is no end to the succession of deeper and deeper theories.
Wherever the truth lies, no one can question the tremendous success of science in explaining the world, including its origin, evolution, and possible future demise. Now we know the structure of atoms, how we inherit and pass on traits, how a cell grows into an organism and how to convert matter into energy. The fact that we can send unmanned spacecraft to Mars and other planets with great precision shows that science gives us an accurate picture of the reality out there. Although science is getting ever more complex, there seems to be no barrier that will prevent us from gaining further knowledge about the world, the universe and ourselves. Perhaps we will hit a ceiling at some point, but we have not reached it, not yet.
All this scientific knowledge has been built on the foundations left by earlier scientists. As we have seen, this process is messy, and it does not always follow a straight path. As we have also seen, scientists and philosophers have developed several tools and “best practice” methods, subsumed under the term “scientific method”, that can help differentiate between science and pseudoscience. While not infallible, these can be enormously effective. How we respond to global challenges such as climate change and global warming will depend on our collective scientific literacy, which is why learning about what science is all about may be a matter of life or death. In this case, ignorance is not bliss.
[1]Popper, K. R. (1962). Conjectures and refutations: The growth of scientific knowledge. New York: Basic Books [2]See, e.g., Stunkel, K. (2012). Fifty Key Works of History and Historiography. Routledge. Felman, S. (1987). Jacques Lacan and the adventure of insight: Psychoanalysis in contemporary culture. Harvard University Press. [3]Jogalekar, A. (2014). Falsification and its discontents. Scientific American. Jan 24, 2014. [4]See e.g., Sozzi, M. (2008) Discrete Symmetries and CP Violation: From Experiment to Theory, Oxford University Press. [5]Horgan, J. (2017). Why String Theory Is Still Not Even Wrong, Scientific American, Apr 27, 2017. [6]Dawid, Richard (2013). String theory and the scientific method. Cambridge University Press. [7]Ellis, G., & Silk, J. (2014). Scientific method: Defend the integrity of physics. Nature, 516, 321–323 [8]Resnik, D. B., & Shamoo, A. D. (2016). Reproducibility and research integrity. Accountability in Research, 24, 116–123. [9]“Politicized scholars put evolution on the defensive,” by Jodi Wilgoren, The New York Times, August 21, 2005. [10]See, e.g., Wikipedia, https://en.wikipedia.org/wiki/Intelligent_design. [11] Kitzmiller v. Dover Area School District, 04 cv 2688 (December 20, 2005). Whether ID Is Science, p. 69 and Curriculum, Conclusion, p. 136. [12]Pigliucci, M. (2018). Nonsense on Stilts: How to Tell Science from Bunk (2nd edition). University of Chicago Press. [13]Shelley, M. (2006). Empiricism. In F. English (Ed.), Encyclopedia of educational leadership and administration. (pp. 338–39). Thousand Oaks, CA: Sage Publications. [14]Shelton, J. W. (2004). Homeopathy: How it really works. Amherst, New York: Prometheus Books. See also Collins, N. (April 18, 2013). “Homeopathy is nonsense, says new chief scientist.” The Daily Telegraph. Retrieved September 9, 2013. [15]Hansson, S. O. & Zalta E. N. “Science and Pseudo-Science". Stanford Encyclopedia of Philosophy. Retrieved 6 July 2012. [16]Kuhn, T. S. (1996). The structure of scientific revolutions, University of Chicago Press, p122.
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