Logical Fallacies: No True Scotsman

Before plunging into the logical nitty-gritties of “no true Scotsman” fallacies, let me tell you about a monkey who could never win at badminton.

The story, which I originally heard on a radio show I loved as a kid, takes place in a jungle full of animals who mostly loved to play badminton. One particular monkey, however, perpetually failed to score any points—until he decided that the easiest way to “win” a game is to change the rules. If he missed hitting the birdie, he claimed a point. If the wind changed direction, he claimed a point. Eventually, though, the monkey learned the hard way that society can’t function without absolutes—and that rules which can mean anything mean nothing at all.

Like a monkey trying to win a game by changing the rules, “no true Scotsman” fallacies happen when someone tries to win an argument by changing the definitions of relevant keywords.

The Monkey and the Scotsman

So, what does a badminton-playing monkey have to do with the faulty form of logic dubbed the “no true Scotsman” fallacy? Like a monkey trying to win a game by changing the rules, “no true Scotsman” fallacies happen when someone tries to win an argument by changing the definitions of relevant keywords. The classic example goes like this:

Arguer: No Scotsman would put sugar in his porridge.

Respondent: My uncle is a Scotsman, and he puts sugar in his porridge.

Arguer: But no true Scotsman would put sugar in his porridge.

What just happened there? The arguer began by making a sweeping generalization which the respondent refuted with a counterexample. The fallacy occurred when the arguer then went back and changed the definition of Scotsman to work around the counterexample.

You can catch this fallacy by applying Check #4 of the Seven Checks of Critical Thinking, “check the definitions.” In this case, you could check whether the definition of being a Scotsman has anything to do with putting sugar in porridge. If not, you’ve detected a “no true Scotsman” fallacy.

The Scientist and the Scotsman

Where do “no true Scotsman” fallacies pop up in worldview contexts? One common example is the claim that no “true scientist” rejects the idea of evolutionary origins. My critical thinking textbook, for instance, stated, “On every count [creationism] shows itself to be inferior. Scientists are then justified in rejecting creationism in favour of evolution—and this is exactly what they do.”1

That quote leaves no room for exceptions. Neither does a quote in the draft report of a resolution titled The Dangers of Creationism in Education, which the Parliamentary Assembly of the Council of Europe passed in 2007.2 The report stated, “At present, scientists from all nations, races and religions agree on the existence of evolution and accordingly no longer try to find out whether it has actually taken place but “how” this has happened.”3

Is that true? Let’s think about it. First, what’s the definition of scientist?4 To answer, we need to define science. As other articles explain in detail, this requires distinguishing between two types of science: observational science, which uses the scientific method to describe and investigate facts in the present, and historical science, which draws conclusions about the past using assumptions based on facts in the present.5

Different scientists have access to the same observational facts but interpret those facts differently through their different worldviews. Because observational facts are the same for everyone, it makes sense to define scientists as people who professionally study or document these facts. In other words, the definition of scientist is based on the definition of observational science, not on scientists’ individual beliefs about the past.

As other resources document, many scientists do interpret observational science through the lens of the Bible.6 A few historic and modern examples include Carl Linnaeus, who pioneered modern taxonomy; Louis Pasteur, whose microbiological discoveries have preserved countless lives; Richard Owen, who coined the word dinosaur;7 Dr. Russell Humphreys, whose model accurately predicts planetary magnetic fields; and Dr. Raymond Damadian, who developed the MRI. Ultimately, implying that no “true scientist” believes creation requires manipulating the definition of scientist—and is therefore a classic “no true Scotsman” fallacy.

The Bible and the Scotsman

Do creationists use “no true Scotsman” fallacies too?8 I’ve read a paper from the journal Evolution: Outreach and Education which said so.9 According to the article, creationists use the No True Scotsman fallacy if they claim that professing Christians who were involved with atrocities in the past, like Nazism, were not “true Christians.”

To answer, we can first ask, “What’s the definition of a Christian?” Biblically, we could respond that a Christian is someone who wholeheartedly believes on Jesus for salvation, like Romans 10:9 says. And while only God knows everyone’s heart, Scripture indicates that consistent Christ-followers will—by definition—follow Jesus’ teachings, for He said, “If you love me, you will keep my commandments.”10

In this sense, no consistent Christian would willfully commit atrocities. This observation does not contain a “no true Scotsman” fallacy because it does not require manipulating the definition of Christian. Besides, the creationist whom the journal article quoted didn’t actually say that “no true Christian” would ever act inconsistently with Jesus’ teachings. Rather, the quote pointed out that Nazi atrocities were inconsistent with Jesus’ teachings but consistent with evolutionary teachings.

“No true Scotsman” arguments are fallacies when they require redefining a term. But they’re not fallacies if they’re consistent with a pre-existing definition, like what it means to follow Christ.

Summing Up

To summarize, “no true Scotsman” arguments are fallacies when they require redefining a term, like scientist. But they’re not fallacies if they’re consistent with a pre-existing definition, like what it means to follow Christ. The key to recognizing and responding to “no true Scotsman” arguments, therefore, is to check the definition of whatever the arguer is generalizing, whether Scotsmen, scientists, Christians, or anything else. Then, we can respond in gentleness and respect (1 Peter 3:15) if we find that arguers have been “monkeying” with definitions.