I am trying to describe an assumption as a common and conventional one. No one ever doubts its reasonableness, and everyone simply takes this assumption as granted without thinking about it.

Can I call such an assumption as "a de facto assumption"? If not, what adjective should I use? I feel "conventional assumption" does not catch my intended connotation.


A de facto assumption isn't bad.

An assumption shared by a people group or audience can be called a commonplace.

In ancient rhetoric, Aristotle developed the concepts of topoi, loci communes, and commonplaces. Within the invention process of rhetoric, the topoi (topics) are basic categories of relationships among ideas, each of which can serve as a template or heuristic for discovering things to say about a subject which a given audience will accept. "Topics of invention" means literally "places to find things," or loci communes.

Aristotle divided these into the "Common" and "Special" topics of invention, with the former being more general and the latter pertaining to each of the three branches of oratory (viz., deliberative, forensic, and epideictic).

Of the seven common topics, a commonplace (or de facto assumption, to use your phrase) would likely fit under the topic of "testimony"; specifically, proverbs and maxims. You can find some common assumptions in American culture in the following maxims/proverbs:

  • Haste makes waste.

  • A stitch in time saves nine.

  • Honesty is the best policy.

  • Confession is good for the soul.

  • The Republican Party is for conservative, big-money types who want to hold on to what they've made through their own efforts and hard work.

  • The Democratic Party is for liberals who believe that wealth is meant to be shared among the less fortunate and the downtrodden in society and that wealth is often made off the backs of the poor.

| improve this answer | |

It is a reasonable assumption.

Others can see its reasonable nature and agree with it.

The instant case may be a fallacy:

"Of course, the earth is flat," they said, until it was proved a fallacy.

| improve this answer | |
  • Actually, I mean the opposite. What I am trying to say is: the assumption is actually not reasonable. Everyone just either assumes it to simplify the problem or blindly follows the mainstream, taking this assumption as granted. I am different in that I challenge its unreasonableness. So, yes, this is the connotation that I am trying to express. – Sibbs Gambling Oct 25 '14 at 15:25
  • You may be challenging its validity -- its reasonableness stays. – Kris Oct 25 '14 at 15:42
  • Btw, I get your point, that it "appears reasonable and so everyone blindly agrees." – Kris Oct 25 '14 at 15:45

If word play is your objective, then it's fine.

It was once a de facto assumption that the earth sits on the back of a giant turtle. Being an assumption, the only fact about it is that it was a common assumption among certain people. That's the way it was, de facto, regardless of why is was assumed.

If you want to give weight only to point that it is a common assumption, you are better off using words like your suggestion - conventional. The acceptance of word choice should not appear to validate the truth of an assumption.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.