5X5 Episode 54

5X5 Episode 54
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January 21st 2009
5X5 53	5X5 55
Skeptical Rogues
S: Steven Novella
R: Rebecca Watson
B: Bob Novella
J: Jay Novella
E: Evan Bernstein
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Skepticism 101 - False Dichotomy

You're listening to the Skeptics' Guide 5x5, five minutes with five skeptics, with Steve, Jay, Rebecca, Bob and Evan.

S: This is the SGU 5X5, and this week's topic is the logical fallacy known as the false dichotomy. Now, a false dichotomy is essentially splitting up a continuum or multiple choices into two extremes; it's either black or it's white, there is no gray in the middle.

E: For example, you might have heard someone say that evolution science is in disarray, so creation science must be correct. Well, no, that's ... not correct at all.

S: Yeah, basically it creates an 'either or' choice, you can call it the 'forced choice': It's either A or B, it's not B, so it must be A. The forcing of the choice between A and B is the logical fallacy. Because it's not necessarily true that there is only A or B, maybe there's C, D, E, F and G as well. So until you establish that, it's the assumption that there's only these two things. So, as I alluded to, there's many forms of this, there's limiting choices from many to two artificially, excluding other possible choices. Or sometimes there is a smooth continuum, you could take many attributes, like height, for example, the world doesn't divide into 'short' and 'tall' people, that would be a false dichotomy. There's a continuum of height from the smallest to the tallest human being. Here's an example we came across recently, this one I think is a good example of the false dichotomy as the excluded middle, denying the middle between two extremes. We recently covered the topic on the SGU of global warming, and one of our listeners commented that if you believe in man-made global warming, then we should be doing everything we possibly can to limit it, and if you don't believe in it, then you don't have to do anything. That was the false dichotomy that he was generating. My position was quite in the middle of those two, and I think it's not that we have to panic, and dismantle our civilization so that we stop emitting carbon dioxide, or we do nothing and we pretend that it doesn't exist. How about saying it may exist, so let's do reasonable things that are more of a win-win situation, let's take some prudent steps to limit our CO2 production without completely dismantling our economy, because global warming seems like it's probably true, and even with the uncertainty, we can take the middle-ground and that's perfectly reasonable.

B: So it's very important to examine all these other options and alternatives that might be available, but remember, don't go to extremes with it. You don't have to consider hypotheses that are unfalsifiable claims. Like, it wouldn't do any good to say to somebody "hey, you haven't eliminated the possibility of a psychic big-foot from a parallel dimension stealing your car". Just use Occam's razor to shave those away, those aren't really necessary.

J: and for the most part, you just need to guard yourself against this tactic or lack of logic, because this is a very common mistake people will make in their logic when they're trying to convince people of things.

S: This is one that we encounter almost on a daily basis. What's also interesting is that there's a flip-side to this called the false continuum, where people might deny the existence of extremes because they aren't discrete choices. So, for example, we can talk about the difference between science and pseudoscience, it is true that claims are not 100% pseudoscience or 100% science, there is a continuum all the way through, so you want to avoid the false dichotomy. But that doesn't mean we can't talk about science versus pseudoscience. It doesn't mean that at the extreme ends there aren't things that are mostly psudoscientific, and claims that are mostly legitimate science. So using the false dichotomy [read continuum], or over-using it in order to deny that we can meaningfully think about and talk about extremes. Some people are really tall, even though height is a continuum, and there is not some objective demarcation line between short and tall.

S: SGU 5x5 is a companion podcast to the Skeptics' Guide to the Universe, a weekly science podcast brought to you by the New England Skeptical Society in association with skepchick.org. For more information on this and other episodes, visit our website at www.theskepticsguide.org. Music is provided by Jake Wilson.