Understanding the 'No True Scotsman' Fallacy

Fallacies of Ambiguity

Proud Scotsman
Proud Scotsman. tirc83/Vetta/Getty

Have you ever heard the argument "no true Scotsman"? It's a common statement used in debating or concluding a particular point that attempts to compare the actions, words, or beliefs of one person -- the Scotsman -- to all Scotsmen. This is a common logical fallacy that is inherently false due to its generalization and vagueness.

Of course, the word 'Scotsman' can be replaced with any other word to describe a person or group.

It can refer to any number of things as well. Yet, it is a perfect example of a fallacy of ambiguity as well as a fallacy of presumption.

Explanation of the "No True Scotsman" Fallacy

This is actually a combination of several fallacies. Since it rests ultimately on shifting the meaning of terms — a form of equivocation — and begging the question, it receives special attention.

The name "No True Scotsman" comes from an odd example involving Scotsmen:

Suppose I assert that no Scotsman puts sugar on his porridge. You counter this by pointing out that your friend Angus likes sugar with his porridge. I then say "Ah, yes, but no true Scotsman puts sugar on his porridge."

Obviously, the original assertion about Scotsmen has been challenged quite well. In attempting to shore it up, the speaker uses an ad hoc change combined with a shifted meaning of the words from the original.

Examples and Discussion

How this fallacy can be used is perhaps easier to see in this example from Anthony Flew's book "Thinking about Thinking — or do I sincerely want to be right?":

"Imagine Hamish McDonald, a Scotsman, sitting down with his Press and Journal and seeing an article about how the 'Brighton Sex Maniac Strikes Again'. Hamish is shocked and declares that "No Scotsman would do such a thing". The next day he sits down to read his Press and Journal again and this time finds an article about an Aberdeen man whose brutal actions make the Brighton sex maniac seem almost gentlemanly. This fact shows that Hamish was wrong in his opinion but is he going to admit this? Not likely. This time he says, "No true Scotsman would do such a thing"."

You can change this to any other bad act and any group you like to get a similar argument — and you'll get an argument which has probably been used at some point.

A common one which is often heard when a religion or religious group is criticized is:

Our religion teaches people to be kind and peaceful and loving. Anyone who does evil acts certainly isn't acting in a loving manner, therefore they can't really be a true member of our religion, no matter what they say.

But of course, the exact same argument can be made for any group — a political party, a philosophical position, etc.

Here is a real-life example of how this fallacy can be used:

Another good example is abortion, our government has such a small Christian influence that the courts have ruled it's ok to kill babies now. Typical. The people who support legalized abortion but claim to be Christians don't really follow Jesus — they have lost their way.

In an effort to argue that abortion is wrong, it is assumed that Christianity is inherently and automatically opposed to abortion (begging the question). In order to do this, it is further argued that no one who supports legalized abortion for any reason can really be a Christian (equivocation through an ad hoc redefinition of the term "Christian").

It is common for a person using such an argument to then proceed to dismiss whatever the "alleged" members of the group (here: Christians) have to say. This is because they are fakes who are lying to themselves at the very least and, arguably, lying to everyone else.

Similar arguments are made regarding a host of controversial political, social, and economic questions: real Christians can't be for (or against) capital punishment, real Christians can't be for (or against) socialism, real Christians can't be for (or against) drug legalization, etc.

We even see it with atheists: real atheists can't have irrational beliefs, real atheists cannot believe in anything supernatural, etc. Such claims are especially bizarre when involving atheists since atheism is defined by nothing more or less than simply the absence of belief in gods.

The only thing a "real atheist" cannot do is be a theist at the same time.