Developing your scientific skepticism: The Middle Ground Fallacy

Poor reasoning is common, even among those with scientific backgrounds. But you too can become a scientific skeptic. The other night on Twitter, pharmacy student and self-proclaimed skeptic Ciara Ní Chionnaith asked the following question:

Skeptics – was there a particular turning point after which you became skeptical? After an experience, a book, meeting/hearing someone etc?

For me, there were two turning points. The first was discovering the Respectful Insolence blog – the only place I could initially find science-based thinking on pharmacy-sold products like homeopathy. Shortly after I started following the blog, I read Carl Sagan’s The Demon Haunted World – Science as a Candle in the Dark, which I’ve reviewed before. There was no turning back, then. This book was eye-opening, to say the least. Not only did it force me to question assumptions I’d held for most of my life, it completely changed my mindset and philosophy about the importance of science and the scientific process. Sagan’s book is a truly essential read for anyone that is interested in finding out more about scientific skepticism. I can’t recommend it enough.

There were a number of other excellent responses to Ciara’s post, which I’ve Storified for your reading interest.

After reflecting on Ciara’s post a bit more, I thought it might be interesting and helpful to readers to do some short posts highlighting common logical fallacies that are routinely seen in health and medicine. As you become a scientific skeptic, spotting logical fallacies is easy. But it takes time to learn them, and to spot them when they’re in use. I’ve noted many in prior posts, but today’s article in the BMJ from Edzard Ernst is a good place to start. I’m a big fan of Dr. Ernst – his book, Trick or Treatment, written with Simon Singh is another essential read, particularly for pharmacists.  His post today was on the “Middle Ground Fallacy” which is also called the “False Balance” fallacy:

When we are confronted with two opposing views, we tend to look for the comfort of the middle ground hoping the truth might lie somewhere between the two extremes. For instance, if someone describes a play, a book, or a restaurant as brilliant and another person thinks it is awful, we might feel that, in fact, it probably is of moderate quality.

But, in many areas, this simplistic logic does not apply. If someone says the earth is flat and another person insists that it is a sphere, we cannot very well conclude the truth lies somewhere in the middle. Facts are facts and disagreements about facts cannot be settled by half-truths or semi-facts.

Middle ground reasoning is endemic in media coverage of many alternative health practices, whether it’s homeopathy, useless laboratory tests, or diet products. Arguments that there is a “middle ground” between homeopathy not working and working are fallacious, given the overwhelming scientific evidence that homeopathy is inert and has no meaningful biologic effects. In the same way, proponents for IgG food intolerance claim that testing is “evolving” or that anecdotes are relevant when there is no published evidence to demonstrate it is useful, and there is good scientific evidence to demonstrate it is useless. Yet when these topics are discussed in the media, often unscientific perspectives are given equal consideration, even though one may be completely unsupported by scientific facts. Creating a middle ground with false balance is a way of creating a debate, when in fact there is no scientific debate at all. Homeopaths will argue that homeopathy is effective, but from a scientific perspective, there is no uncertainty at all about it, or its lack of effects.

These type of arguments remind me of this classic Dara O’Briain clip (the key point starts at 1:00):

One of the few areas in science and medicine where the middle ground is less frequently observed is in discussions of vaccine safety. Over the past few years there has been a significant increase in general awareness that antivaccine positions are not based in credible science – and antivaccine advocates don’t argue in good faith. Consequently, less consideration is now given to antivaccine viewpoints – which, from a scientific evidence perspective, is the right approach.

The key point for the developing skeptic to keep in mind is that the “middle” (however defined) is not always the wrong answer. In areas of legitimate scientific debate, a moderate position may be correct. But a middle position, just like any position, must be supported by good evidence. So when the science is clear, and the facts are on your side – don’t equivocate, and don’t yield to a middle ground.

More reading:

Edzard Ernst: The “middle ground” fallacy
Fallacy: Middle Ground
Your logical fallacy is: middle ground

Photo from flickr user miheco under a CC licence.