Either or vs Neither nor

[DlarehAtsok]

The LR Bible explains that Either A or B implies (logically contrary to the layman use) that at least one of the variables must be chosen, albeit both may be selected. What about neither A nor B? My idea is that being the logical opposite of either or, it must be that none of the variables can be chosen but I am not sure why? Why cannot it have the reverse effect of either or and imply that at least one of the variables cannot be chosen? Thanks in advance!

[Dave Killoran]

Hi D,

Yes, you are correct that neither/nor means both are not selected. Neither/nor is a shortening of "not either and not or," and the "not either" was contracted to "neither" and the "not or" became "nor." Thus, a phrase like "Neither A nor B" means "not A AND not B."

From a logical standpoint, neither/nor is indeed the opposite of either/or. As we know, either/or means one or both of the variables, and thus the opposite will not include those possibilities, leaving only "zero" of the variables being selected.

Thanks!