Ginkgo biloba: How psuedoscience becomes science

Ginkgo biloba is a species of plant that has been used in traditional Eastern medicine for thousands of years for memory enhancement and to treat dementia. Until recently, it has been largely ignored by modern medicine as one of hundreds of herbal medicines that have no real, verifiable benefit. It was largely considered to a pseudo-medicinal plant that was used by the "natural medicine" crowd that largely reject science-based medicine. That is not entirely the case any more, thanks to the careful work of a group of researchers that decided to test its effects while maintaining the rigorous standards set forth in the medical and scientific community.

Pierre Le Bars and his colleagues wanted to test if Ginkgo biloba could be used to safely treat symptoms of dementia in patients with Alzheimer's, so they set forth on creating a rather standard, time-tested experimental design -- a placebo-controlled, double-blind, randomized trial with a fairly large sample size (309). Great care was taken to control extraneous variables and prevent bias, which is exactly what makes this such a good study.

Since Le Bars and company only wanted to test for the effects of Ginkgo biloba on patients' symptoms of dementia, they only selected patients with no other serious medical problems. This is an important control that helped the scientists make sure that no other condition was either negatively or positively affecting the patients' symptoms. Le Bars and his colleagues also controlled for the placebo effect, which is a phenomenon that causes some people to have either perceived or real improvement in a medical condition even though the treatment has no real pharmacological effect. They did this by giving part of the sample a placebo (a sham medicine containing no active ingredients) whilst telling the patients they are receiving Ginkgo biloba. This group is known as the control group, while the group that actually receives the Ginkgo biloba is known as the experimental group. This allows the researchers to compare the two groups. Ginkgo biloba could only be said to have a real benefit to these patients if it performs significantly better than the placebo. If it works equally well, than taking Ginkgo biloba could be said to be no better for dementia than taking sugar pills.

Le Bars and the other researchers were also aware that they had to be careful not to allow bias to slip into the study and skew the results. To do this, they implied a tried-and-true technique: they double-blinded the study. Blinding a study simply means that you keep which group is getting the placebo and which is getting the real thing a secret to the patients. This prevents the patients who are getting the placebo from knowing, therefore allowing the placebo effect to work. Double-blinding a study means that both the patients and those administering the treatment don't know which is placebo and which is not. This prevents the researchers from either consciously or subconsciously giving away any hints to the patients, and is further protection from bias. Le Bars, et al. also prevented bias by utilizing standardized tests for dementia that were applied in a consistently-controlled manner. So, this study was set up in a fashion that made it all-but-impossible to influence one way or the other, as neither the researchers nor the patients had a clue who was getting the real thing and measurements were taken in the exact same manner every single time.

The fact that 309 subjects were used in this study also adds to its validity, because one cannot perform meaningful statistical analysis on a small sampling of subjects. With a small sample size there is more of a chance that outliers will skew the results, there is less certainty that the selected individuals represent the general population, and there is more of a chance that extraneous variables enter into play in a significant role.

So, what did Le Bars and his crew find? Astonishingly, what was at the time most often dismissed as a bogus remedy actually was found to have a significant effect on patients already suffering from dementia. By the end of the 52-week study, the experimental group fared much better than the control group. In fact, the control group continued to decline while the experimental group's symptoms actually improved over the year. What was once pseudoscience is actually being taken seriously in the scientific community now because of this evidence. That doesn't mean it's all over, though. Other scientists are still having a bit of trouble replicating the study, and studies that investigated Ginkgo biloba's effects on preventing the onset of dementia have come up empty handed. Clearly, more work needs to be done, but the important part of the story is that this natural remedy is being taken seriously by the scientific community because people playing by the rules of science found something very interesting. This is predominantly because the scientific community, as well as the mind of the individual scientist, is primed to change its views when new, credible evidence is presented.

The Study:

Le Bars, P.L., M.M. Katz, N. Berman, T.M. Itil, A.M. Freedman, and A.F. Schatzberg. 1997. A placebo-controlled, double-blind, randomized trial of an extract of Ginkgo biloba for dementia. North American EGb Study Group. The Journal of the American Medical Association 278(16):1327-1332. (PDF)

Inductive Reasoning vs. Faith

Many religious people tend to argue that non-religious, skeptical individuals have as much faith in their beliefs as they do theirs. This, I think, is a misunderstanding around the means that a skeptic incorporates certain beliefs into their belief system. Most of a skeptic's knowledge is accumulated through inductive reasoning. Inductive reasoning is the process of deriving general principles from specific instances or observations. It is uncertain, and only deals in probability as opposed to certainty, but it is nonetheless a powerful tool in acquiring useful, meaningful knowledge. And, to people unfamiliar with it, it appears a bit like faith instead of an application of critical thought.

The key difference between inductive reasoning and faith is that inductive reasoning is based upon statistical probabilities when having "faith in something" implies that there is no real reason other than an emotional or 'spiritual' apprehension to believe in it. Take, for instance, the inductive principle "lead sinks in water at STP (standard temperature and pressure)." What this is really saying is, "based upon an extensive amount of past data being consistent and unchanging in confirming the general principle 'lead sinks in water at STP,' it is probable to the highest degree that new observations will continue to confirm this as a generally applicable principle." Since that's quite a mouthful, the short hand version is a bit easier to use in regular conversation. But, as we can see, the long-hand version takes absolutely no faith, just a rather basic understanding of statistical probabilities. Predicting that a specific instance will result in lead floating in water at STP is simply as silly as betting on number 39 when playing roulette (the wheel only goes to 38). The odds are so stacked against it that it is entirely unreasonable to believe it, and thus entirely reasonable to believe the contrary -- that lead will sink, and that the roulette wheel will land on a number ranging from 0-38 (or 00). No faith required.

Skepticism - “Extraordinary Claims Require Extraordinary Evidence”

Many people who are not familiar with skepticism are introduced to it through the rather vague remark that "extraordinary claims require extraordinary evidence." What many of these individuals do not realize is that the idea of something being "extraordinary" to a skeptic has a bit more meaning than it does to the general public. Although this may seem obvious to any diligent student of skepticism, I doubt that much of the general public has read David Hume, or even Carl Sagan for that matter. So, here I will try to give a brief introduction on what a skeptic means when he uses these terms. 

First and foremost, almost anyone you run into that happens to call themselves a skeptic will likely be what's known as a empirical (or scientific) skeptic, that is they question the validity of claims that lack empirical evidence. As far as I know, this line of thinking has much of its roots in the writings of David Hume, and is spelled out explicitly in his empiricist tome An Enquiry Concerning Human Understanding. Empirical skeptics accept the epistemological view that contingent claims (claims dealing with the way things are in fact) cannot be verified through deduction alone, but can only be instead verified by experience. For example, an empirical skeptic would say that for us to conclude that lead sinks in water is not a product of logical necessity, but instead it is our experience of that fact that leads us to the conclusion that it in fact sinks. 

This, however, illuminates a problem, known as the problem of induction. According to Hume, we develop a sense of how things are in fact through induction (deriving principles from specific instances) as opposed to deduction (deriving specific instances from principles), but induction is inherently imperfect as a means of acquiring knowledge. Where a conclusion necessarily follows from its premises in deductive reasoning, that is not the case with induction. This leaves us with an inherent uncertainty in the validity of all contingent claims. Going back to our example, we must conclude that just because our experience is that lead sinks in water does not necessarily mean that that is always the case. The descriptive principle, "lead sinks in water," is tentative and by no means certainly true. In the empiricist's view, however, the more a principle is confirmed by experience, the more certain we can become of its validity. We can reasonably expect that lead will sink in water because it has always done so in the past.

So, in this context, an "extraordinary claim," as opposed to being a mere claim to the unusual, is the complete opposite of this sort of empirically supported claim. It is a claim that isn't confirmed by experience, and may even be contradicted by it. The claim, "lead floats in water," is an extraordinary claim. That is not a matter of subjective opinion, but a statement that our cumulative experience, mainly our extensive understanding of physics, contradicts this claim. Disregarding trickery or other extraneous variables, lead sinks in water every time anyone tries to test it.

So, when a skeptic says that Jesus rising from dead is an extraordinary claim, we are actually pointing to the body of evidence produced by the study of human physiology, as well as our cumulative experience that people stay dead after being dead for three days. 

The next step is to establish what an empirical skeptic means by “extraordinary evidence.” Extraordinary evidence is empirical evidence that meets the rigors of the scientific method. There are a few basic criteria for this type of evidence: it must be testable, falsifiable, and robust. The first two are so intertwined that they are hard to separate from one another in an explanation.

The concept that ideas need to be tested in order to be justified is the foundation of the scientific method. For, if you can not test an idea, you simply cannot determine if it is true or false. To believe in something without putting it to a proper test is to simply take it on the claimant's say-so. 

A proper test requires that we are able to distinguish between a world where a claim is true and a world where the claim is false. Thus, the principle of falsifiability comes into play. If a claim is falsifiable, that means that there is a possible test for which, if certain conditions are met, that the claim can be discredited. For example, the claim that "all men are immortal," is easily falsified through the observation of a single dead man. If, however, a claim is unfalsifiable, then it cannot be tested. For, a world in which an unfalsifiable claim is true is completely indistinguishable from a world in which it is false. Thus, such claims are entirely worthless, and warrant extreme skepticism.

For example, in A Demon Haunted World, Carl Sagan proposed to his readers that a dragon lived in his garage. When you went to look in his garage, however, he told you that it was an invisible dragon. When you tried to spread flour on the floor to see its footprints, Mr. Sagan explained that the dragon floated. When you tried to detect the heat of the fire that it spewed from its mouth with infrared sensors, he was so kind to explain to you that the fire it breaths is heatless. And, when you finally decided to spray paint the dragon, he told you that it was an incorporeal dragon. In other words, this dragon is completely beyond our detection. Carl Sagan's claim to its existence is not subject to falsification, and to say that such a dragon exists is rather meaningless, because a universe where such a dragon exists is entirely indistinguishable from one that does not. 

The last factor in considering evidence is its robustness. When claim is robust, that means it is supported by an entire body of evidence, and contradicted by little or no evidence. This is important because one specific piece of evidence tends to never point to a single conclusion, but instead is readily open to interpretation and could easily fit with several or even dozens of different hypotheses. It requires not just one single piece of evidence to support a claim, but an entire body, so that all are pointing towards the validity of that claim without mutually supporting any others. An example of a lack of robustness would be alien abduction claims. It's certainly an interesting phenomenon, given the consistency of the experiences between different individuals and the powerful (and quite real) emotional responses to them. However, in them we have a complete lack of robustness, because there are other (more terrestrial) explanations that explain the phenomenon just fine. A combination of sleep paralysis (of which I'm a rather frequent sufferer), hypnagogic hallucinations, aliens in popular culture, and perhaps even effects of magnetic fields on the brain, all explain the phenomenon as well if not better than the idea that aliens are actually visiting Earth and taking human specimens in their sleep. The evidence doesn't only point to the extraordinary claim, and thus less the extraordinary claims are much more likely. 

What we’ve learned is that the principle "Extraordinary claims require extraordinary evidence" can be, more formally, written as "Claims that are not confirmed by experience, or contradicted by it, require testable, falsifiable, robust empirical evidence in order to justify them." This is the bread-and-butter of skeptical thought, and once you understand and accept this, you are well on your way to becoming a skeptic.

'The Fine Art of Baloney Detection'

Now that I have presented the difference between skepticism and denialism, I want to clear up what exactly skepticism is. Since he is perhaps one of the greatest champion of skeptical thought and is great at demonstrating ideas in a way that is easily understood, I will be borrowing much from Carl Sagan (specifically his chapter in The Demon-Haunted World of the same title as this post).


Sagan described skepticism as a Baloney Detection Kit, which contains the tools "to construct, and to understand, a reasoned argument and -- especially important -- to recognize a fallacious or fraudulent argument."


So, what's in the tool kit? There is a list of do’s and a list of don’ts.


DO
• Independently confirm the "facts" wherever possible.
• Encourage substantive debate on the evidence by knowledgeable proponents of all points of view.
• Spin more than one hypothesis. If there's something to be explained, think of all the different ways in which it could be explained. Then think of tests by which you might systematically disprove each of the alternatives. What survives, the hypothesis that resists disproof has a much better chance of being the right answer than if you had simply run with the first idea that caught your fancy.
• Quantify. If whatever it is you're explaining has some measure, some numerical quantity attached to it, you'll be much better able to discriminate among competing hypotheses.
• Make sure arguments follow. If there's a chain of argument, every link in the chain must work (including the premise) -- not just most of them.
• Use Occam's Razor. This convenient rule-of-thumb urges us when faced with two hypotheses that explain the data equally well to choose the simpler.
• Ask whether the hypothesis can be, at least in principle, falsified. Propositions that are untestable, unfalsifiable are not worth much.
• Perform controlled experiments wherever possible.


DO NOT
• Use arguments from authority, as they carry little weight -- "authorities" have made mistakes in the past. They will do so again in the future. Perhaps a better way to say it is that in science there are no authorities; at most, there are experts.
• Get overly attached to a hypothesis just because it's yours. It's only a way station in the pursuit of knowledge. Ask yourself why you like the idea. Compare it fairly with the alternatives. See if you can find reasons for rejecting it. If you don't, others will.
• Use logical fallacies.


So that's the basic gist of skeptical thinking right there. As someone who is rather innately gullible, I find these tools to be extremely useful.


In fact, everyone tends to find use of skeptical thinking in some aspects of their life. For instance, I am currently looking to buy a car. Most people apply skepticism to such an endeavor. For instance, when I go look at a car tomorrow, I'm going to bring my father (who worked as a mechanic for some time) with me because I really don't know a lot about cars, and I know he can ask the right questions and spot anything obviously wrong. This is what skeptics do, but they apply it to more things than just car purchases. They hopefully apply it to religion, economics, politics, and general claims about how our world works.


I can say with reasonable certainty that skepticism works. Science wouldn't be what it is without skepticism (they are really the same thing), and the world simply wouldn't be the same without science. It is that skepticism that breeds valid claims, and rejects invalid ones. Skepticism allows for a meaningful progression of knowledge; knowledge that we can apply to improve not only our understanding of the world around us, but our mastery of it. But, please, don’t take my word for it — try it for yourself.

Skepticism vs. Denialism

From my experience, quite a few people confuse skepticism with what I (and others) call denialism. Denialism is, quite simply, selective incredulity. For one reason or another, a denialist will, either consciously or subconsciously, choose to dismiss the evidence for a well supported proposition. We see this with fundamentalist Christians with evolution, Moon landing conspiracy theorists with the moon landing (obviously), Global warming "skeptics" with anthropogenic global warming, and "antivaxxers" with innoculation, among many others. These groups are not skeptics. They are arbitrarily incredulous to a specific theory, most of the time due to preconceptions and beliefs that they hold to be true and have an invested interest in maintaining. Skepticism is quite the opposite.


Carl Sagan described skepticism as "the means to construct, and to understand, a reasoned argument and—especially important—to recognize a fallacious or fraudulent argument" (The Demon-Haunted World). Unlike the denialists, skeptics tentatively accept conclusions because there is verifiable evidence to support it and the logic of the claim follows; and they do not accept those arguments that are not supported by the evidence and/or the logic is fallacious. Skeptics do not believe in things because they want them to be true, or because they fit within a preconceived notion of reality. They do not pick and choose from the evidence to fit with their beliefs, but instead acquire their beliefs from the entire body of evidence. Skeptics always prefer to believe in an inconvenient truth than a comforting falsehood. This is quite a contrast compared to denialists.