We learn to count at such an early age that we tend to take the notion of abstract numbers for granted. We know the word "two" and the symbol "2" express a quantity that we can attach to apples, oranges, or any other object. We readily forget the mental leap required to go from counting specific things to the abstract concept of number as an expression of quantity.
Abstract numbers are the product of a long cultural evolution. They also apparently played a crucial role in the development of writing in the Middle East. Indeed, numbers came before letters, contends art historian and archaeologist Denise Schmandt-Besserat of the University of Texas in Austin. In contrast, the traditional view is that the first written words were pictures or hieroglyphs used to represent objects or ideas.