For some people the definition of science is closely linked to the application of what they call “the scientific method”*; a number of them even fail to notice that the scientific method cannot supplant scientific thinking.
“He [Friedrich Weismann] got a colony of mice, and cut off their tails. Then he waited to see whether their children would be born without tails. They were not, as Butler could have told him beforehand. He then cut off the children’s tails, and waited to see whether the grandchildren would be born with at least rather short tails. They were not, as I could have told him beforehand. So with the patience and industry on which men of science pride themselves, he cut off the grandchildren’s tails too, and waited, full of hope, for the birth of curtailed great-grandchildren. But their tails were quite up to the mark, as any fool could have told him beforehand.” George Bernard Shaw (1)
My attention was drawn recently to an article (2) boldly proclaiming “Our data demonstrate that flies raised on organic food extracts by and large performed better on the majority of health tests”, and even more boldly proclaiming: “Our data suggest that organic foods provide improved health outcomes”. The authors used Drosophila melanogaster (fruit flies) as a model to study the alleged health effects of “organic” food. My opinion was that the experiments described in the paper were carried out rigorously, and I had no reason to mistrust their statistical methods or results. Did I then run to my local “organic-food” shop to stock up? Hardly.
Even if the results were reliable their conclusions were clearly flawed, as anyone knowing that flies are insects, could have told them before hand.
In the discussion of the paper the authors attribute their results (longer lifespan, more descendents, etc.) to the beneficial health effects of “organic” foods; the mechanisms of action -they admit- are yet to be determined. The authors never discuss the deleterious effect that insecticides have on insects or that, what they call “conventional” food is grown with, and probably contains at least traces of, insecticides.
It is worth noticing that the evils of insecticides are brought up several times in the introduction of the paper; their allegedly harmful effects, in humans, are expensively listed there. We are even reminded that metabolites of insecticides can be found in infants**. One may think that insecticides are nastier to humans than to flies. The authors never state that the “conventional” food they have used may contain traces of insecticide. They never measured the levels of insecticide that could be negatively affecting the flies. More importantly: they did not included a control where the same amount of insecticide was added to “organic” food in order to test that, under equal conditions, “organic” foods provide health benefits as compared with “conventional” foods. The authors just assumed that “organic” food improved flies’ health because is more nutritious, not because it does not contain insecticides.
After complaining that long-term meta-studies in humans have always failed to show positive health effects of organic foods (3), the authors finally conclude:
“The use of the Drosophila model will be invaluable not only in investigating potential health effects of a variety of food sources, but furthermore in dissecting the molecular pathways underlying the health effects of organic foods”
I would have concluded differently: using insects to compare foods grown with or without insecticide provides the means to test how good insecticides are in accomplishing their goal: killing pests. For anyone wanting to show that “organic” foods are more nutritious and healthier than “conventional” food, using a mammalian model is advised.
To have a pre-conceived much-fancied idea and to invent an inconsistent system to justify it has been the prerogative of many philosophers; it should not be the vice of scientists. We can fancy many things that are not science, and that’s perfectly fine. I like real ale; I like it because I believe it tastes better, it offers more variety and, I must confess, because of the snobbish pleasure of knowing that something has been specially crafted, taking up considerable time and effort. I will not try to promote it by using scare mongering. I will not say that it is better for human health than mass-produced pasteurized generic lagers neither. I will promote it by using the subjective reasons exposed above or just saying: I believe it tastes better and I can afford to pay the extra money it costs.
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* TheOxforddictionary defines scientific method as a procedure consisting of systematic observation, measurement, and experiment.
** The fact that modern mass-spectrometers can detect almost negligible levels of whatever someone wants to find is never mentioned.
(1) Back to Methuselah (1921)
(2) Plos One (2013) Vol 8 e52988 (Click here to see the article)
(3) Am J Clin Nutr (2010) vol 92 p 203-210 (Click here to see the article)