Are these two statements equivalent?
If you don't satisfy either of the conditions A and B
If you don't satisfy both of the conditions A and B
I interpret the "either" case as:
If you fail to meet at least one of A or B.
But the "both" case has me confused when a non-native English speaker questioned me on it. (I'm a native English speaker).
Example of "either" on this page:
To use the self-service application to download and install Office 2016, you’ll need two things:
- Mac OS X 10.10 (Yosemite)
- The self-service software application included on L&S-managed Macs
If you don't meet either of those requirements
Example of "both" on this page:
In the second stage of screening if you meet both of the following requirements you don’t need to do any further assessment of that substance. You’ll need to do detailed modelling of emissions that don’t meet both of the following requirements
My opinion is that using "both" to mean "either" is sloppy and confusing, because it seems like "both" should mean:
you fail to meet A and you fail to meet B
In other words, I think that the "both" case doesn't apply to you if you've satisfied at least one.
Is there a "standard" way to read the "both" statement?