Ever wonder why people call it a PIN number or an ATM machine? Ever hear someone say, “Wherever you go, there you are,” and think to yourself, well, duh? If you have, then you’ve already stumbled upon some common tautologies.
A tautology is, roughly, the act of saying the same thing twice. It is a repetition of meaning through different words, or the use of a concept’s definition as support for that concept. In mathematical terms, it can be expressed as “A=B, therefore A=B.” The second equation tells us nothing new about the first, and that is a tautology’s major flaw – irrelevant information.
For instance, the phrase ‘PIN number’ utilizes an acronym (the first letters of words are used as an abbreviation) to say something redundant: ‘Personal Identification Number number.’ The same applies in the case of the ‘ATM machine’ – ATM already means ‘Automatic Teller Machine.’ Adding the second ‘machine’ doesn’t actually say anything meaningful.
The most insidious tautologies employ a disguised circular logic to make it seem as if a redundant statement is conveying new information. Proponents of aromatherapy often use the definition of smell to suggest that their products have much broader psychological applications. The website Aromatherapy.com, for example, says that inhaling essential oils “is widely believed to stimulate brain function.” The site then advertises oils for use in combating problems like depression.
There is no dispute that smells of all kinds trigger brain functions, just as all sensory stimuli do. However, no one would suggest that you could cure a mental illness by looking at a pretty picture or listening to a happy song. Considered in this way, the argument that aromatherapy works by stimulating the brain becomes an empty echo of itself.
Tautologies are much more common than people sometimes realize, but they can be difficult to catch. One way to root them out is by plugging them into the mathematical format. If you’re not comfortable with that, though, try asking for explanations. Ask for lots of definition and clarification. If you are facing a tautology, the answers will go nowhere pretty fast.