Source of quote

["Peter Flom" <peter.flom@ndri.org>]

I remember reading a quote which was attributed to one of the early 20th 
century physicists (I forget which one), it was something along the lines of
"When we wish to understand the sentence 'one and one equals two' it is not 
enough to understand 'one' and 'two'; we must also understand 'and' and 
'equals'"  but that's not it exactly.
Any help appreciated
Peter