I've always wondered this but never asked. Given this statement:

Energy can be neither created nor destroyed.

Should it be or or nor? This is on Wikipedia so they are probably correct in saying nor but why is this so? In my opinion it sounds like it should be or.

The more I think of it the more I think it can be left up to interpretation or emphasis. For example, it could be interpreted to mean:

Energy = ¬Created ∨ ¬Destroyed


Energy = ¬(Created ∨ Destroyed)

Some help here?

marked as duplicate by Robusto, anongoodnurse, tchrist, MrHen, David M Mar 28 '14 at 23:36

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  • I really like the use of logic notation to make the question clearer. – IQAndreas Apr 1 '14 at 20:28

Neither always goes with nor and either always goes with or, without exception. You certainly can retain or in the negative sense, but not in conjunction with neither. Thus, your notations would be translated into complete sentences thus:

  • Energy = ¬Created ∨ ¬Destroyed ⇒ Energy can be neither created nor destroyed.
  • Energy = ¬(Created ∨ Destroyed) ⇒ Energy cannot be created or destroyed.
  • Isn't it, "Energy can neither be created nor destroyed."? (Note placement of be/neither.) – Kaz Dragon Apr 4 '11 at 10:15
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    @KazDragon: You will probably often see both forms used. However, Jimi's version is traditionally preferred by the very precise, because it is transparent about ellipsis: in neither destroyed nor created, both participles are perfectly parallel; in neither be destroyed nor created, it is be created and destroyed that are made to be parallel, even though they are strictly speaking different parts of speech. You could say neither be destroyed nor be created to complete the parallel, but that wouldn't look as neat. – Cerberus Apr 4 '11 at 12:11
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    No! The first statement is incorrect. Energy = ¬Created ∨ ¬Destroyed means "Energy cannot be created or cannot be distroyed" (which implyes that the narrator does not know whether it cannot be created or cannot be destroyed or that there are two kinds or energy, one cannot be created, the other cannot be destroyed) which has different meaning than "Energy can be neither created nor destroyed" which is essentially the same as "Energy = ¬(Created ∨ Destroyed)" which is equal to "Energy = ¬Created ∧ ¬Destroyed" and means that energy cannot be created AND cannot be destroyed. – Anixx Jan 29 '12 at 6:36

As far as I know, nor should be used if your phrase is already inherently negative, i.e.:

Energy can be neither created nor destroyed.

If you had either there, then or would be used, e.g.:

Energy can be either kinetic or potential.


You use "or" when listing 2 or more elements, usually in positive statements:

It can take 2 or 3 hours to get there by car.

Or you can use it together with "either":

You can have either tea or coffee.

While you use "nor" when you're denying, therefore used in a sentence giving it a negative connotation and is used together with neither:

Neither Jack nor Carl wanted to come to the Stadium.

Jimi gave you the exact examples from your question, and another way of using "or" in negative statements, but at least now you will understand the general rule about this.

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