Can I reword the following sentence to say "Experts

First of all, I assume you want to use the word "claim" as a noun, in which case "experts" must be in the possessive, and really the word "the" should be added for clarity.

Original: The experts' claim that girls are not motivated by chocolates is not true.

Now, is this a simple double negative? This question moves beyond grammar, to questions involving the philosophy of science. There are many claims in science about which science can make neither a definitive affirmation nor a definitive denial. For example, science cannot prove the equation of mind and brain; science can neither disprove the equation of mind and brain. That statement remains one whose truth value has not been ascertained by science, at least not up until the present moment. All kinds of metaphysical and theological questions are in that category --- science has nothing substantial to say either way.

If we take this view --- in this instance, question whether girls are motivated by chocolate is unknowable to science because sufficient evidence one way or the other has not been gathered, then I would avoid the word "true", which is a bit too dogmatic for science, and instead say
The claim that girls are not motivated by chocolates is not supported by evidence.
The claim that girls are motivated by chocolates is also not supported by evidence.
In other words, we don't have sufficient evidence supporting either possibility --- science can pronounce neither one "true" according to the standards of science.

This, of course, gets into major philosophical issues far beyond the simple grammatical analysis the GMAT SC asks of us. If for some reason we are guaranteed that all the issues of philosophy of science do not impinge on this question, and that there are only the binary possibilities of true/false with reference to this claim, and for whatever reason the speaker has complete epistemological access to this truth, then the sentence:
The experts' claim that girls are not motivated by chocolates is not true.
would be grammatically equivalent to the sentence
The experts' claim that girls are motivated by chocolates is true.

This is perhaps not the best example sentence, because the philosophical issues (irrelevant to the GMAT) swamp the more basic grammatical issue (the province of the GMAT SC).

Does all this make sense?

Mike

Mike, Thanks for correcting the possessive part. I missed that " ' ". I am sorry for that.

Thanks again for your thoughtful analysis and guidance.

However, I have a question about the above statement. Let's take another example so that we can avoid philosophical issues. Let's say the sentence says : It is not entirely false that Apple's stock price is not decreasing.

Can I say: it is true that Apple's stock price is increasing, or it is true that Apple's stock price is constant? I don't think so because 'not entirely false', in my opinion, doesn't get translated to "true."

I don't think that in the above sentence, we can cancel out two double negatives. I was taught in high school that *whenever* you see two negatives, cancel them out. This gets a bit confusing on the LSAT or the GMAT because test makers love to play with three state entities such as increasing, decreasing or constant; strengthen, weaken or irrelevant. (If you could let us know some other examples, that would be really helpful.)

I would love to hear your expert thoughts. I hope that other readers will benefit from this conversation as well.

Thanks

OK, first of all, that original sentence is a overgrown monster:
It is not entirely false that Apple's stock price is not decreasing.
You certainly can eliminate the final negative:
It is not entirely false that Apple's stock price is increasing.

Here we get into another subtle issue ---- if the sentence were simply.....
It is not false that Apple's stock price is increasing.
...then we could very easily change that to ----
It is true that Apple's stock price is increasing.
....or even more simply .....
Apple's stock price is increasing.

A phrase like "not entirely false" is a very different beast, and can play any one of a number of complex roles. Two are
1) Litotes --- that's the rhetorical term for emphasis by dramatic understatement.
For example:
"It's not entirely false that Bill Gates has a lot of money."
"George Clooney is not exactly ugly."
"New York City is not quite the tiniest town in the USA."
In all three, we are making a rhetorical statement, emphasize one extreme by ironically denying the opposite. That's litotes. Proper delivery of these lines requires an ironic inflection in the voice --- these sentence don't work when spoken deadpan.
2) Qualifying phrase to set up a contrast--- here, one would grudging admit one thing, but immediately present a fact in the opposite direction.
"It is not entirely false that Apple's stock price is increasing, but the board is worried about a pattern of dropping revenues."
"It is not completely false that Bert is a fast runner, but his tendency to get injured easily casts serious doubts on his prospects as a professional athlete."
That is also a highly rhetorical use of language, typical of, say, the New Yorker magazine, but not quite as likely on the GMAT. Again, delivery would require a sophisticated inflection in the voice.

The point is --- do not think of "not exactly false" as in any way a simple negative. There is absolutely nothing simple about it.

Does that make sense?

Mike