Quote: Confuse Theory w/Reality?

[Guest bonacci]

Greetings:

 

I'm trying to find a quotation. I believe it was Einstein (but may very well be wrong) and it goes something like this: "Be careful not to confuse the mathematical description of a clock with the actual workings of the clock inside the box into which you cannot see."

 

The quotation I'm looking for speaks to the difference between a scientific model which predicts (maybe perfectly) how some phenomenon may behave and the actual, physical, thing.

 

Does anyone know the quote I'm looking for?

 

thanks.