September 6, 2010 1 Comment
What makes scientific ideas (we call them hypotheses) special is that they are testable. We can devise a test (we call them experiments) that will potentially falsify the idea. In other words, we can show that it might be wrong. If we can’t do that after our best experimental efforts, it just might be right. However, there is another reason that scientific ideas are special: they are reasonable. They are based upon what we already know about how the world works. There are good reasons to dream up the idea in the first place. Examining the underlying explanatory model behind any claim is a good first step in determining its validity.
Explanatory models are underlying frameworks that people use to explain the world. Broadly speaking, the explanatory model of the scientific method is materialism. That is to say, the universe and everything in it is the result of material interactions. Simply put, there is nothing beyond the material (natural) world, and magic (supernatural) isn’t real. You may call this a philosophy or a belief, and you might be right, but at least there is evidence for this perspective, and it serves us well when we are trying to figure out how the world works.
We can get more specific than this. Specific disciplines have specific explanatory models. For instance, one explanatory model of illness in real medicine is the germ theory of disease. The theory of gravity underpins much of what we understand in physics and astronomy. In pharmacology, dose responses and ligand-receptor interactions explain the action of many drugs, both clinical and elicit. These explanatory models are based upon how the world really works and are backed up by truckloads of data derived from experimental investigation. There are good reasons for physicians to suspect that some disease processes are the result of infectious pathogens.
What drives me over the deep end is when scientific sounding ideas are advanced in a public forum that have no basis in reality. Pseudoscience does this all the time. Their explanatory models are rubbish, and this is one very easy way to detect them.
Here’s an example, and forgive me for shooting fish in a barrel for the sake of an argument. Homeopathy subscribes to an explanatory model that is in complete contrast to what we know about chemistry and pharmacology. In short, they claim that if you (1) take a substance that when administered, causes symptoms similar to those experienced by a patient complaining of some ailment and (2) administer a minute dose (one that has been serially diluted and shaken) of this substance by mouth, the patient suffering the ailment will be cured. This idea is suspect for two reasons. Firstly, the substance chosen seems completely arbitrary, only that some reference book tells them that it will elicit symptoms similar to the patient complaint, but has nothing whatsoever to do with the ailment. Secondly, and more problematic, the substance is diluted with water to such a degree that there is likely not a single molecule of this substance left in the preparation. It’s water. This is ridiculous because it is the exact opposite to the well-accepted notion in pharmacology that the higher the dose of an active substance, the larger the biological response.
There are good reasons for the S-shape of the above dose-response curve, which are beyond the discussion here. But what is clear from the figure is that the higher the dose administered (horizontal axis), the larger the resulting response (vertical axis). Simple. You know this is true. You perform a dose-response experiment every morning with your coffee. The more sugar you put in your coffee, the sweeter it tastes.
This is all bad enough for the homeopath. But it gets worse, and here is where homeopathy’s explanatory model comes in. Their explanatory model is this: the water has memory. As the substance is serially diluted and shaken, it remembers the original substance and somehow (they don’t say how), this water preparation cures the ailment. But it gets worse yet. When you buy a homeopathic remedy in a magic shop, it’s often in the form of a pill. The pill must be made of something solid. This is, of course, sugar. So, in order for their explanatory model to be correct, not only must the diluted and shaken water preparation remember, it must transfer its memory to the sugar. Magic.
It’s not my place to speculate why someone would come up with an idea like this in the first place; we all have silly ideas from time to time. However, most of us have the good sense to recognize them for what they are the next morning after running it by our friends in the pub. This idea, however, made it out of the pub and persisted. Today, there are so called “complementary and alternative medicine” (CAM) practitioners who prescribe these remedies to their clients. They, and the companies who produce, market and sell these remedies, are making good money from this. Furthermore, there is no good evidence that the reported effects of these remedies are anything other than the placebo effect. We should have dropped this idea like a bad hangover the day after it was initially proposed by German physician Samuel Hahnemann in 1796 after his 12th pint of hefeweizen in the biergarten.
But here is my point. There is no good reason that we should have expected that this would have worked in the first place. The explanatory model is vacuous. You either believe in magic or you don’t. Pick door number two, especially when we are talking about our health.
To me, this is a good test of any scientific or medical claim. If the explanatory model is not in accord with what we already know about reality, then it doesn’t deserve the ink used to write its name. I should be a little more charitable toward Dr. Hahnemann, as he and his contemporaries in the pub that night didn’t know what we now know about the world. It was a different time, and besides, who doesn’t talk a little trash after a few pints? My quarrel isn’t with him, it is with those who continue to live in his time when it comes to selling sugar pills to the unsuspecting, vulnerable and uninformed, who are just looking for a solution to what ails them. Despite the fact that this idea made no sense in the first place and in the face of good experimental evidence against it (as if we needed to bother), they have the hubris to advance this idea on the vunerable for money.
Now, people are free to believe what they want and spend their hard earned money on whatever they fancy. But the reason this makes me so mad is that there are real treatments available for most of what ails us, many of which are provided and paid for by our nice socialist health care system. Unfortunately, some people will take a pass on real treatments for real ailments because they are persuaded by CAM practitioners’ magical explanations and their persistent arguments that real medicine is evil. If pseudoscience wins the hearts and minds of the public, people will seek out things like chelation therapy over conventional cancer treatment, as an example. If people choose treatments that are useless against serious illnesses, then at best they are no more likely to recover than if they had stayed home and, at worst, in some cases could have additional harm caused by the “treatment”.
If an explanatory model is fantasy, then the best we can hope for is that the placebo effect will exert its power (which, by the way, is not magic). If someone feels better after a “treatment” with something useless, it’s either the placebo effect at work, or they feel better because they would have felt better the next day anyway. So, the best pseudoscience can do is help accidentally because the mechanisms they ascribe to their “treatment” are wrong. In the case of real medicine, the explanatory models happen to be correct: pathogens cause disease; cancerous cells divide too fast and hog nutrients from healthy tissues; blocked blood flow to brains and hearts cause tissue death; holes in blood vessels cause blood loss and shock; etc. Sure, medical treatments may not work all the time, because not everything is treatable and medicine isn’t perfect. Sometimes medical treatments also cause damage (it’s called iatrogenesis, and we should be critical of that too). But at least we have a shot based upon reality and something more than wishful thinking.
So, we can easily look under the hood of any claim to see if it will run. You don’t even need to know the details. Just find out what the explanatory model is, and then you’ll have a nice little shortcut to see if you should bother paying attention.