Redundant negatives

Let's go to town and see if we can't buy some new T-shirts.

Why is it that many English people use a negative construction in the following example when a positive meaning is meant? For instance:

• "Let's go to town and see if we can't buy some new T-shirts" (what is actually meant is they want to see if they can buy some T-shirts)
• "You ought to see if you can't get a job with your uncle" (what is actually meant is you ought to see if you can get a job with your uncle)
• "Mary kicked out her husband after his affair" - "I should thinknot!" (what is meant is "I should think so!")

Of course, in all these examples the correct, positive construction is also used often, but what perplexes me is why do the negative constructions - essentially meaning the complete opposite of what is intended - even exist in these circumstances? Would I be correct in believing them to be ungrammatical?

Gareth Rees answers:

Hello. Thank you for writing to us at BBC Learning English and for asking a rather unusual, and puzzling, question. Let's see if I can't answer it.

Before I go into the detail concerning your question, I first of all want to say that the following two sentences are grammatically correct:

• Let's go to town and see if we can't buy some new T-shirts.
• You ought to see if you can't get a job with your uncle.

Also, as you mention, we can communicate the same idea by using a positive sentence grammar. For example:

• Let's go to town and see if we can buy some new T-shirts.
• You ought to see if you can get a job with your uncle.

So, the question is, why do we use the strange negative version? I have given this a lot of consideration and I think that the idea is that the speaker is giving the sentence extra emphasis by using this unusual negative form. 

Basically, rather than suggesting we try to do one thing, instead we check whether the opposite of that thing is impossible. If the opposite is impossible, then the thing we want to do must be possible. I hope that isn't too confusing! 

Looking at your T-shirt example, perhaps the speaker's friend has been complaining because he hasn't got any nice T-shirts to wear, and perhaps he feels that he can't find any good ones in the shop. The speaker then says, 'well, let's see if you are right? You think we can't find any new T-shirts, let's see if that is true. Let's go to town see if we can't find any new T-shirts.'

So, by making a sentence which says we should try to disprove a negative, we will actually see if the positive is possible. By looking at the world with this view, with this strange but true logic, we are giving emphasis to the sentence, because our language is choice is unusual.

So, Kypros, why don't you read or listen to this explanation again and see if you can't understand it.

About Gareth Rees

Gareth Rees has a BA (hons) in History and Philosophy of Science, CTEFLA, and DELTA. He has taught EFL, EAP and Business English in China, Spain and England, and he is the co-author of the Language Leader Elementary and Pre-Intermediate English language course books (Pearson Longman). He currently teaches English in the Language Centre at the University of the Arts, London.

From: BBC Learning English - http://www.bbc.co.uk/worldservice/learningenglish/