July 01, 2010

False dichotomy fallacy

APOLOGIABy Hendrik van der Breggen
(The Carillon, July 1, 2010)

False dichotomy fallacy

A fallacy is a mistake in reasoning. Some fallacies are so common that logicians have given them names. Today we will look at the false dichotomy fallacy.

Logician Trudy Govier defines a false dichotomy as follows: “An either/or split that omits alternatives.” Govier adds: “to think that everything is either black or white would be to believe in a false dichotomy.” Of course, the truth of the matter is that there are shades of grey as well as shades of red, orange, yellow, green, and so on.

The false dichotomy fallacy is sometimes also called the false alternatives fallacy. Why? Because, as logician Edward Damer explains, “[t]his fallacy consists in assuming too few alternatives and, at the same time, assuming [mistakenly] that one of the suggested alternatives must be true.”

Some examples may be helpful.

Let’s say that I tell you it must be either hot or cold outside today. This is a false dichotomy because there are other alternatives that are omitted. It could simply be warm.

Or consider this. Years ago I heard a shrewd if not somewhat unscrupulous businessman speculate on how Orange Julius could improve its business. (Orange Julius sells delicious frothy fruit drinks which, in the 1980s, could be made even frothier and more delicious—and more expensive—by adding a raw egg into the blender.)

To boost revenue, the businessman (who, for the record, was not an OJ employee) suggested that Orange Julius staff should ask each customer: “Would you like one egg or two?” The hope was that customers would spend more money because of their failure to realize that there is a third (less expensive) option: No eggs.

The false dichotomy fallacy can be much more problematic morally.

In presentations of what to do with terminally ill patients we are often presented with only two options: physician-assisted suicide, or a lonely agonizing death. Sadly, often missing is a third alternative—i.e., palliative or hospice care—wherein a dying patient is given genuine comfort and pain is minimized.

Also, in discussions of stem cell research (which promises the almost miraculous healing of Parkinson’s Disease, Alzheimer’s, diabetes, etc.) we are sometimes presented with only two options: harvest stem cells from human embryos (which are human beings at their tiniest), or stop the research. Missing from such discussions is the realization that there are various other alternatives, such as using adult stem cells from human blood, bone-marrow, umbilical cords, and even fat—alternatives that are proving to be successful plus don’t involve killing human beings at their first stage of life.

(So not all stem cell research must be embryonic stem cell research. We can favour adult stem cell research, wherein no human being dies, yet be opposed to the morally-problematic embryonic stem cell research, wherein human beings are deliberately destroyed.)

In a conversation over what to do with frozen human embryos left over from In Vitro Fertilizations (which help infertile couples get pregnant) a scientist once presented me with two options: dump the frozen human embryos into the garbage, or do research with them.

My scientist friend was willing to do experiments on the human embryos—human beings—because, she argued, putting them into the garbage would be such a waste. We’re going to destroy them one way or the other, after all, so let’s do it in such a way that increases our stock of knowledge. Significantly, however, she neglected considering a third, more ethical alternative: i.e., making the frozen embryos available for adoption.

It turns out that such adoptions actually occur. Next time you’re online, check out the webpage for Snowflakes Frozen Embryo Adoption Program, which is a part of Nightlight Christian Adoptions.

The false dichotomy fallacy – it really only takes some imagination and creativity not to be fooled by it.

(Hendrik van der Breggen, PhD, teaches ethics and critical thinking at Providence College, Otterburne, Manitoba, CanadaThe views in this column do not always reflect the views of Providence.)


Scott said...

A good post, well written. Particularly necessary to be aware of this fallacy when it is so often used, as you point out, to make the other party look the idiot/fool/evil in certain moral situations.

Keep up the good work. God bless.

Hendrik van der Breggen said...

Thanks Scott. It's nice to receive positive feedback.

P.S. Your website looks really interesting. I'll be investigating further as time permits.

Jordan said...

Hi Dr. V, did you know that your post on the false dichotomy fallacy is featured on Apologetics315's weekly bonus links?


Hendrik van der Breggen said...

Thanks Jordan. I didn't know that my post was listed on Apologetics315's weekly bonus links. I think very highly of Apologetics315, so I take their acknowledgement of my post as additional positive feedback! Positive feedback is truly an encouragement. (G.E.D. Thanks, too, to Brian at Apologetics315.)

Kane Augustus said...

The Law of Non-Contradiction (LNC) and the fallacy of False Dichotomy (FD) were out walking one day.

Turning his syllogism to regard FD, LNC quipped, "I've been thinking about you lately, and it occurs to me that you're either a false dichotomy, or you're not."

Slowing from a brisk modus pollens to a casual modus tollens, FD regarded LNC. Smirking FD returned with, "According to our mutual friend, the Law of Identity, it would be contradictory to state that I'm anything other than what I am. I am only that that I am, nothing else."

LNC, cooly calculating his next thought, spoke up, "Of course. Come on! We're going to be late meeting with Begging the Question, and you know how she gets when she spends too much time with Ad Hoc. Anything could happen!"

Picking up their cumulative case, the pair sped along their path to Deduction-ville.

The end.

Hendrik van der Breggen said...


Do Marijuana plants get burned in the forest fires in the Canadian North? Is it smoky in your neck of the woods? I’m pretty sure that logic + pot does not equal philosophical clarity!

Speaking of clarity, it may be helpful for Apologia readers to understand the false dichotomy fallacy (a.k.a. false alternatives fallacy) in terms of contradiction and contrary. Here are some comments from philosopher T. Edward Damer (from page 56 of his fine book Attacking Faulty Reasoning, 2nd edition):

“A common form of the fallacy of false alternatives derives from the failure to differentiate properly between contradictories (negatives) and contraries (opposites). Contradictories exclude any gradations between their extremes; there is no middle ground between a term and its negative, for example, between hot and not hot. Contraries, on the other hand, allow a number of gradations between their extremes; there is plenty of middle ground between a term and its opposite, for example, between hot and cold. The problem is that contraries are often treated as if they were contradictories. In the case of contradictories (a term and its negative), one of the two extremes must be true and the other false: It is either hot or it is not hot. In the case of contraries (a term and its opposite), it is possible for both extremes to be false: It could be neither hot nor cold. To assume that it must be either hot or cold would be to treat contraries as if they were contradictories and thereby commit the fallacy of false alternatives.”

Also, it may be helpful to keep in mind that the principle (law) of non-contradiction (PNC) states the following: Nothing can both be and not-be, at the same time and in the same sense. PNC involves a dichotomy, but not a false dichotomy. PNC is a logical truth, which is to say that it’s necessarily true.

PNC = [not (A and not-A)]. If A is true, then not-A is false; if A is false, then not-A is true; either way, (A and not-A) is false, which is to say that PNC—the denial of (A and not-A)—must be true.

Contraries, on the other hand, are not necessarily true. Where A and B are opposites, Contrary = A or B, such that if A is true, then B is false; and if B is true, then A is false; but if B is false, A could be false too, because of C; or if A is false, B could be false too, because of C. (Substitute A = hot, B = cold, C = warm.)

Deduction-ville? Is that the place we send our tax returns?

Best regards,

Kane Augustus said...

The story's actually pretty clever, Dr. V. Read it again. It's full of irony.

And, yes, marijuana does get burned in the forest fires up here. Though I haven't been privileged enough to catch the draft of any of those fires.