- 2-minute read
- 6th January 2015
Word Choice: Rational vs. Rationale
The words ‘rational’ and ‘rationale’ are easy to get confused. On paper the only difference is the ‘-e’ at the end of the latter. However, although not terms you’ll hear often in everyday life, it’s vital to know the difference in academic writing.
Why? Both ‘rational’ and ‘rationale’ have important places in academic writing. You may, for example, be asked to provide a ‘research rationale’ as part of a study, or to discuss ‘rational solutions’ to a problem. As such, confusing the two can affect the clarity of your written work.
Rational (The Quality of Being Reasonable)
The adjective ‘rational’ means ‘in accordance with reason’. Thus, when we decide something on the basis of facts, we say it was rational. Likewise, if someone is scientific or logical, we might say they’re a ‘rational person’:
Since the weather is rainy and I don’t like getting wet, it would be rational to use an umbrella.
The opposite of ‘rational’ is ‘irrational’, which we might use if someone bases their decisions entirely on their emotions or incomplete information.
It’s also worth noting that, in a mathematical context, you may encounter the idea of ‘rational’ and ‘irrational’ numbers. A rational number is one which can be represented as a fraction, but this is a specialised use of the term ‘rational’.
Rationale (A Reason for Doing Something)
A noun rather than an adjective, the main meaning of ‘rationale’ is ‘a reason for doing something’. It is thus what we give to explain or justify our actions:
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My rationale for using an umbrella is the combination of wet weather and my dislike of getting wet.
In academic writing, a ‘research rationale’ is an explanation for why studying something will be beneficial.
Rational or Rationale?
The words ‘rational’ and ‘rationale’ are linked insofar as a ‘rationale’ should give ‘rational’ reasons for something. For example, the desire to stay dry when is a rational reason (i.e. a rationale) for owning an umbrella. This similarity in meaning, as well as spelling, makes these words easy to mix up.
However, keep in mind that ‘rational’ is an adjective and ‘rationale’ a noun and you should be able to avoid errors. Remember:
Rational (adjective) = The quality of being reasonable
Rationale (noun) = A reason for a decision, action or belief
