Tautology

Tautology Definition

There are several definitions for tautology. The one relevant here is the linguistic, rhetorical definition (as opposed to the logical, mathematical definition).

This is a broad definition, but it's also the most accurate because even in linguistic contexts people use the word tautology in many ways. Depending on how you use it, a tautology can be a rhetorical device, a figure of speech, or a stylistic error.

That said, here's one way to narrow it down. This is the most common usage of tautology in linguistics and denotes a stylistic error.

You might be wondering what this looks like. A few examples should help.

Fig. 1 - Typically, you don't want to use tautologies.

Tautology Examples

There are many examples of tautology. Here's a simple one to start.

This is a tautology because men are human beings by definition.

That said, this particular tautology has its uses. It may help remind someone to treat others with respect and dignity. Another potentially useful tautology is, "It is what it is." This expression carries no denotative usefulness. However, connotatively, people know it means, "I (or you) must accept this situation."

However, many tautologies are considered stylistic errors because they contain neither denotative nor connotative information.

This sentence contains no useful information. By definition, a wide-open situation means that anything could happen. Thus the redundancy in this sentence is tautological.

Proximity is essential in defining a tautology. Usually, a tautology exists in one or two sentences. The pieces of it need to connect clearly. A tautology is not saying the same thing at the beginning and end of a paragraph, for example.

In fact, some tautologies are common two-word pairings. This is one way that tautologies creep into everyday language.

Tautology Language

Most tautologies that exist in everyday language are pointless. Here are some common tautologies:

"Armed gunman"

• By definition, a gunman is armed.

"Free gift"

• By definition, a gift is free.

"Personal opinion"

• By definition, opinions are personal.

"Necessary requirement"

• By definition, a requirement is necessary.

"Over-exaggerate"

• This doesn't mean anything different from "exaggerate."

"Nuclear weapons of mass destruction"

• By definition, nuclear weapons create mass destruction.

"Died from a fatal wound"

• By definition, fatal wounds kill.

To avoid tautologies in your own writing, check yourself as you write. You might use a tautology on accident.

Self-Eliminating Tautologies

One other kind of tautology is the self-eliminating kind.

That looks like this:

None of these phrases communicate anything overtly useful. However, self-eliminating tautologies can add emphasis to a situation. For example, one boyfriend might say to the other, "We love each other, or we don't," to draw attention to the problems in their relationship. It might represent a call to fix the relationship or call it off entirely.

Fig. 2 - Self-eliminating tautologies can say: make a choice!

Tautology vs. Pleonasm

Tautology and pleonasm are not utterly distinct. Although humans have an innate desire for clear distinctions, no one sat in a room with the brand new words "tautology" and "pleonasm" and divided them into mutually exclusive camps. Nor has any universally consistent or agreed-upon distinction been reached by linguists.

In reality, tautology and pleonasm have complex etymological histories, and their meanings overlap or differ depending on who you ask. That said, there is some sense to be made of the situation.

You can see how this definition is similar to the definition of tautology. However, the definition of pleonasm focuses on something different than the definition of tautology.

Here, the definition of pleonasm focuses on superfluous words.

On the other hand, the definition of tautology focuses on the repetition of ideas.

So although both result in a repetition of sorts, they arrive at this repetition in somewhat different ways. Here's a pleonasm:

"Fiery burning" is technically an overuse of words, because both "fiery" and "burning" say the same thing. To prevent the pleonasm, this sentence could as easily begin with "The fire in her heart..." or "The burning in her heart..." The sentence would lose no context.

Here's a similar sentence that is better described as a tautology:

By definition, burning is a fire spreading, so this sentence equates two identical ideas as if they were different. This sentence is aptly a tautology because the idea is redundant.

A pleonasm is more likely to be used as a literary device (to express emphasis or perhaps clarity), whereas a tautology is more often poor style.

Tautology and Contradiction

A tautology differs more drastically from a contradiction than it does from a pleonasm.

Here's a contradiction:

By definition, to "solve" something, you have to understand it. There's a minuscule chance John guessed the correct answer to the math problem, but he couldn't possibly explain how he arrived at that answer — a requirement to actually solve the problem.

Here's a tautology that includes similar information:

This statement is redundant because, as you know, solving a math problem requires math by definition. Therefore, the above statement serves no useful purpose. It could as easily be, "John solved a math problem."

This covers the main kinds of tautology in linguistics and how to tell them apart from other concepts.