# Can a double negative be used to express caution or uncertainty?

In the following statement, what is the effect of the double negative? Is it necessarily emphasis? Or could it be a kind of cautious statement implying a degree of uncertainty? If a double negative can be used to express caution, how can it be distinguished from cases used for emphasis?

None of the cells appeared not to have divided.

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This is just an badly phrased attempt at writing the logic: "There does not exists an X, where X is a cell, where NOT(X appeared to have divided)", which if you simplify the logic is equivalent to "For all X where X is a cell, X appeared to have divided". Hence the phrase means it looks like all of the cells have divided. See here for more on double negatives: ell.stackexchange.com/questions/829/… – Matt Apr 9 '13 at 10:31

If the null hypothesis was "The cells will not divide" and your experimental data indicates that all the cells did divide, then the sentence you cite could be a very formal way of saying that the null has been rejected. It is, however, a very forced (even clumsy) construction.

I understand why you interpret "appeared" to suggest a degree of uncertainty, but I do not believe it to be justified. In this context it simply means "were observed".

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It can be distinguished by the context.

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I COMPLETELY agree with Fortiter - the example above is an extremely specific example, where there has been a previous null hypothesis and, therefore, one could argue that the double negative structure is a legitimate, formal method of stating the result of an experiment.

Ordinarily, I would suggest that a double negative would be an incredibly awkward way of expressing uncertainty. With the vast vocabulary available to us in the English language, why would you use a double negative (itself inherently uncertain, as you have mentioned above) to express uncertainty?

Barrie also makes an excellent point regarding context. So much in English is governed by context. This, in my experience, is one of the most difficult aspects of the language for non-native speakers to grasp. Subtle differences in context can have a massive influence on the emphasis and, indeed, sometimes the meaning of an entire grammatical structure.

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