According to Michael Spivak's book on calculus, in his initial discussion of the basic properties of numbers, he talks about 1 not being equal to 0 in regards to the existence of a multiplicative identity property. He does attempt a brief explanation as to why this needs to be stated, however, his meaning is still very unclear to me. Can someone please clarify this for me?
He is a link to the book in google books. It is P6 on pp. 5-6.
Calculus - Google Books