On Science Skeptics and Deniers

Do all climate change skeptics also question the theory of evolution? Do anti-vaccinationists also believe that GMO foods are unsafe? As we’ll see in this post, scientific skepticism and “science denial” are much more nuanced than most people think.

To begin with, scientific skeptics on hot-button issues such as climate change, vaccination and GMOs (genetically modified organisms) are often linked together as anti-science deniers. But the simplistic notion that skeptics and deniers are one and the same – the stance taken by the mainstream media – is mistaken. And the evidence shows that skeptics or deniers in one area of science aren’t necessarily so in other areas.

The split between outright deniers of the science and skeptics who merely question some of it varies markedly, surveys show, from approximately twice as many deniers as skeptics on evolution to about half as many deniers compared to skeptics on climate change.

In evolution, approximately 32% of the American public are creationists who deny Darwin’s theory of evolution entirely, while another 14% are skeptical of the theory. In climate change, the numbers are reversed with about 19% denying any human role in global warming, and a much larger 35% (averaged from here and here) accepting a human contribution but being skeptical about its magnitude. In GMOs, on the other hand, the percentages of skeptics and deniers are about the same.

The surveys also reveal that anti-science skepticism or denial don’t carry over from one issue to another. For example, only about 65% of evolutionary skeptics or deniers are also climate change skeptics or deniers: the remaining 35% who doubt or reject evolution believe in the climate change narrative of largely human-caused warming. So the two groups of skeptics or deniers don’t consist of the same individuals, although there is some overlap.

In the case of GMO foods, approximately equal percentages of the public reject the consensus among scientists that GMOs are safe to eat, and are skeptical about climate change. Once more, however, the two groups don’t consist of the same people. And, even though most U.S. farmers accept the consensus on the safety of GMO crops but are climate change skeptics, there are environmentalists who are GMO deniers or skeptics but accept the prevailing belief on climate change. Prince Charles is a well-known example of the latter.

Social scientists who study such surveys have identified two main influences on scientific skepticism and denial: religion and politics. As we might expect, opinions about evolution are strongly tied to religious identity, practice and belief. And, while Evangelicals are much more likely to be skeptical about climate change than those with no religious affiliation, climate skepticism overall seems to be driven more by politics – specifically, political conservatism – than by religion.

In the political sphere, U.S. Democrats are more inclined than Republicans to believe that human actions are the cause of global warming, that the theory of evolution is valid, and that GMO foods are safe to eat. However, other factors influence the perception of GMO food safety, such as corporate control of food production and any government intervention. Variables like demographics and education come into the picture too, in determining skeptical attitudes on all issues.

Lastly, a striking aspect of skepticism and denial in contemporary science is the gap in opinion between scientists and the general public. Although skepticism is an important element of the scientific method, a far larger percentage of the population in general question the prevailing wisdom on scientific issues than do scientists, with the possible exception of climate change. The precise reasons for this gap are complex according to a recent study, and include religious and political influences as well as differences in cognitive functioning and in education. While scientists may possess more knowledge of science, the public may exhibit more common sense.

Next week: Use and Misuse of the Law in Science

Why Creation Science Isn’t Science

According to so-called creation science – the widely held religious belief that the world and all its living creatures were created by God in just six days – the earth is only 6,000 to 10,000 years old. The faith-based belief rejects Darwin’s scientific theory of evolution, which holds that life forms evolved over a long period of time through the process of natural selection. In resorting to fictitious claims to justify its creed, creation science only masquerades as science.    

Creation science has its roots in a literal interpretation of the Bible. To establish a biblical chronology, various scholars have estimated the lifespans of prominent figures and the intervals between significant historical events described in the Bible. The most detailed chronology was drawn up in the 1650s by an Irish Archbishop, who calculated that exactly 4,004 years elapsed between the creation and the birth of Jesus. It’s this dubious calculation that underlies the 6,000-year lower limit for the age of the earth. 

Scientific evidence, however, tells us that the earth’s actual age is 4.5 to 4.6 billion years. Even when Darwin proposed his theory, the available evidence at the time indicated an age of at least a few hundred thousand years. Darwin himself believed that the true number was more like several hundred million years, based on his forays into geology. 

By the early 1900s, the newly developed method of radiometric dating dramatically boosted estimates of Earth’s age into the billion year range – a far cry from the several thousand years that young-Earth creationists allow, derived from their literal reading of the Bible. Radiometric dating relies on the radioactive decay of certain chemical elements such as uranium, carbon or potassium, for which the decay rates are accurately known.

To overcome the vast discrepancy between the scientifically determined age of the earth and the biblical estimate, young-Earth creationists – who, surprisingly, include hundreds of scientists with an advanced degree in science or medicine – twist science in a futile effort to discredit radiometric dating. Absurdly, they object that the method can’t be trusted because of a handful of instances when radiometric dating has been incorrect. But such an argument in no way proves a young earth, and in any case fails to invalidate a technique that has yielded correct results, as established independently by other methods, tens of thousands of times.

Another, equally ridiculous claim is that somehow the rate of radioactive decay underpinning the dating method was billions of times higher in the past, which would considerably shorten radiometrically measured ages. Some creationists even maintain that radioactive decay sped up more than once. What they don’t realize is that any significant change in decay rates would imply that fundamental physical constants (such as the speed of light) had also changed. If that were so, we’d be living in a completely different type of universe. 

Among other wild assertions that creationists use as evidence that the planet is no more than 10,000 years old are rapid exponential decay of the earth’s magnetic field, which is a spurious claim, and the low level of helium in the atmosphere, which merely reflects how easily the gas escapes from the earth and has nothing to do with its age.

Apart from such futile attempts to shorten the earth’s longevity, young-Earth creationists also rely on the concept of flood geology to prop up their religious beliefs. Flood geology, which I’ve discussed in detail elsewhere, maintains that the planet was reshaped by a massive worldwide flood as described in the biblical story of Noah’s ark. It’s as preposterously unscientific as creationist efforts to uphold the idea of a young earth.

The depth of the attack on modern science can be seen in polls showing that a sizable 38% of the U.S. adult public, and a similar percentage globally, believe that God created humans in their present form within the last 10,000 years. The percentage may be higher yet for those who identify with certain religions, and perhaps a further 10% believe in intelligent design, the form of creationism discussed in last week’s post. The breadth of disbelief in the theory of evolution is astounding, especially considering that it’s almost universally accepted by mainstream Churches and the overwhelming majority of the world’s scientists.

Next week: On Science Skeptics and Deniers

What Intelligent Design Fails to Understand about Evolution

One of the threats to modern science is the persistence of faith-based beliefs about the origin of life on Earth, such as the concept of intelligent design which holds that the natural world was created by an intelligent designer – who may or may not be God or another deity. Intelligent design, like other forms of creationism, is incompatible with the theory of evolution formulated by English naturalist Charles Darwin in the 19th century. But, in asserting that complex biological systems defy any scientific explanation, believers in intelligent design fail to understand the basic features of evolution.

The driving force in biological evolution, or descent from a common ancestor through cumulative change over time, is the process of natural selection. The essence of natural selection is that, as in human society, nature produces more offspring than can survive, and that variation in a species means some offspring have a slightly greater chance of survival than the others.  These offspring have a better chance of reproducing and passing the survival trait on to the next generation than those who lack the trait.

A common misconception about natural selection is that it is an entirely random process. But this is not so. Genetic variation within a species, which distinguishes individuals from one another and usually results from mutation, is indeed random. However, the selection aspect isn’t random but rather a snowballing process, in which each evolutionary step that selects the variation best suited to reproduction builds on the previous step.

Intelligent design proponents often argue that the “astonishing complexity” of living cells and biological complexes such as the bacterial flagellum – a whip-like appendage on a bacterial cell that rotates like a propeller – precludes their evolution via the step-by-step mechanism of natural selection. Such complex systems, they insist, can only be created as an integrated whole and must therefore have been designed by an intelligent entity.

There are several sound scientific reasons why this claim is fallacious: for example, natural selection can work on modular units already assembled for another purpose. But the most telling argument is simply that evolution is incremental and can take millions or even hundreds of millions of years – a length of time that is incomprehensible, meaningless to us as himans, to whom even a few thousand years seems an eternity. The laborious, trial-and-error, one-step-at-a-time assembly of complex biological entities may indeed not be possible in a few thousand years, but is easily accomplished in a time span that’s beyond our imagination.     

However, evolution aside, intelligent design can’t lay any claim to being science. Most intelligent design advocates do accept the antiquity of life on earth, unlike adherents to the deceptively misnamed creation science, the topic for next week’s post. But neither intelligent design nor creation science offers any scientific alternative to Darwin’s mechanism of natural selection. And they both distort or ignore the vast body of empirical evidence for evolution, which includes the fossil record and biodiversity as well as a host of modern-day observations from fields such as molecular biology and embryology.

That intelligent design and creation science aren’t science at all is apparent from the almost total lack of peer-reviewed papers published in the scientific literature. Apart from a few articles (such as this one) in educational journals on the different forms of creationism, the only known paper on creationism itself – an article, based on intelligent design, about the epoch known as the Cambrian explosion – was published in an obscure biological journal in 2004. But one month later, the journal’s publishing society reprimanded the editor for not handling peer review properly and repudiated the article. In its formal explanation, the society emphasized that no scientific evidence exists to support intelligent design.

A valid scientific theory must, at least in principle, be capable of being invalidated or disproved by observation or experiment. Along with other brands of creationism, intelligent design is a pseudoscience that can’t be falsified because it depends not on scientific evidence, but on a religious belief based on faith in a supernatural creator. There’s nothing wrong with faith, but it’s the very antithesis of science. Science requires evidence and a skeptical evaluation of claims, while faith demands unquestioning belief, without evidence.

Next week: Why Creation Science Isn’t Science

When No Evidence Is Evidence: GMO Food Safety

The twin hallmarks of genuine science are empirical evidence and logic. But in the case of foods containing GMOs (genetically modified organisms), it’s the absence of evidence to the contrary that provides the most convincing testament to the safety of GMO foods. Although almost 40% of the public in the U.S. and UK remain skeptical, there simply isn’t any evidence to date that GMOs are deadly or even unhealthy for humans.

Absence of evidence doesn’t prove that GMO foods are safe beyond all possible doubt, of course. Such proof is impossible in practice, as harmful effects from some as-yet unknown GMO plant can’t be categorically ruled out. But a committee of the U.S. NAS (National Academy of Sciences, Engineering and Medicine) undertook a study in 2016 to examine any negative effects as well as potential benefits of both currently commercialized and future GMO crops.

The study authors found no substantial evidence that the risk to human health was any different for current GMO crops on the market than for their traditionally crossbred counterparts. Crossbreeding or artificial hybridization refers to the conventional form of plant breeding, first developed in the 18th century and continually refined since then, which revolutionized agriculture before genetic engineering came on the scene in the 1970s. The evidence evaluated in the study included presentations by 80 people with diverse expertise on GMO crops; hundreds of comments and documents from individuals and organizations; and an extensive survey by the committee of published scientific papers.

The committee reexamined the results of several types of testing conducted in the past to evaluate genetically engineered crops and the foods derived from them. Although they found that many animal-feeding studies weren’t optimal, the large number of such experimental studies provided “reasonable evidence” that eating GMO foods didn’t harm animals (typically rodents). This conclusion was reinforced by long-term data on livestock health before and after GMO feed crops were introduced.

Two other informative tests involved analyzing the composition of GMO plants and testing for allergens. The NAS study found that while there were differences in the nutrient and chemical compositions of GMO plants compared to similar non-GMO varieties, the differences fell within the range of natural variation for non-GMO crops. 

In the case of specific health problems such as allergies or cancer possibly caused by eating genetically modified foods, the committee relied on epidemiological studies, since long-term randomized controlled trials have never been carried out. The results showed no difference between studies conducted in the U.S. and Canada, where the population has consumed GMO foods since the late 1990s, and similar studies in the UK and Europe, where very few GMO foods are eaten. The committee acknowledged, however, that biases may exist in the epidemiological data available on certain health problems.

The NAS report also recommended a tiered approach to future safety testing of GMOs. The recommendation was to use newly available DNA analysis technologies to evaluate the risks to human health or to the environment of a plant –  grown by either conventional hybridization or genetic engineering – and then to do safety testing only on those plant varieties that show signs of potential hazards.

While there is documentation that the NAS committee listened to both sides of the GMO debate and made an honest attempt to evaluate the available evidence fairly, this hasn’t always been so in other NAS studies. Just as politics have interfered in the debate over Roundup and cancer, as discussed in last week’s post, the NAS has been accused of substituting politics for science. Further accusations include insufficient attention to conflicts of interest among committee and panel members, and even turning a blind eye to scientific misconduct (including falsification of data). Misconduct is an issue I’ll return to in future posts.

Next week: What Intelligent Design Fails to Understand About Evolution