Word Confusion: Rational versus Rationale

Posted July 6, 2015 by Kathy Davie in Author Resources, Editing, Self-Editing, Word Confusions, Writing

It’s only one letter. Who knew it could make such a difference.

A difference between being logical and not crazy, you know, normal. To think clearly, to be coherent, clear, methodical.

Then there’s the rationale for reasons, having principles, justifying your thinking, using logic.

Word Confusions…

…started as my way of dealing with a professional frustration with properly spelled words that were out of context in manuscripts I was editing as well as books I was reviewing. It evolved into a sharing of information with y’all. I’m hoping you’ll share with us words that have been a bête noir for you from either end. Consider sharing this Word Confusion with friends by tweeting it.

Consider the following:
What is your rational in this instance?

What numbers are you using?

What is your rationale in this instance?

What are your reasons?

You’re not being rational.

You’re crazy.

You’re not being rationale.

You’re not being “purpose”??

What is the rational behind dropping pesticides on crops?

It involves weighing risks and benefits.

What is the rationale behind dropping pesticides on crops?

The reason is that it increases the yield by suppressing the weeds.

What is the rational behind adding baking soda to cupcake batter?

One rule of thumb is to use ¼ teaspoon per cup of flour.

What is the rationale behind adding baking soda to cupcake batter?

Well, the reason you add baking soda is so your cake will rise.

Rational Rationale
Credit to: Apple Dictionary.com; Merriam-Webster

Spock at the console

Image by NBC Television [Public domain], via Wikimedia Commons

Spock is the epitome of rational.

Costco sign notifies shoppers of a limitation on food

Image courtesy of I, BrokenSphere [GFDL, CC-BY-SA-3.0 or CC BY-SA 2.5-2.0-1.0], via Wikimedia Commons

The rationale for the limit was a 2008 shortage on rice.

Part of Grammar:
Adjective 1; Noun 2 Noun
Not crazy

Based on or in accordance with reason or logic

  • [Of a person] Able to think clearly, sensibly, and logically
  • Endowed with the capacity to reason

[Mathematics; of a number, quantity, or expression] Expressible, or containing quantities that are expressible, as a ratio of whole numbers

[Medical] Using medical treatments based on reason or general principles — used especially of an ancient school of physicians

[Mathematics] rational number


A set of reasons or a logical basis for a course of action, a particular belief, practice, or phenomena

An underlying reason

I’m sure there’s a perfectly rational explanation.

Andrea’s upset — she’s not being very rational.

Man is inherently a rational being.

When expressed as a decimal, a rational number has a finite or recurring expansion.

A rational number is one that can be represented as the ratio of two whole numbers.

A rational number is a real number that can be written as a simple fraction, i.e., as a ratio.

He explained the rationale behind the change.

Okay, so what’s your rationale behind this?

Supposedly, the rationale for tightening the digital security grip is to track potential foreign cyber-threats.

The rationale of a search warrant escaped his attention.

The original rationale for Daylight Savings Time in the last century was to save fuel for the war efforts.

Adverb: rationally
Noun: rationality
History of the Word:
First known use: 14th century

1 Middle English racional is from the Anglo-French racionel, which is from the Latin rationalis, which is from ration-, ratio.

2 First known use: 1606

Late Middle English in the sense of having the ability to reason from the Latin rationalis, from ratio(n-) meaning reckoning or reason.

Mid-17th century from the modern Latin. It’s neuter when used as a noun from the Latin rationalis meaning endowed with reason.

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C’mon, get it out of your system, bitch, whine, moan…which words are your pet peeves?