What+is+four

=What is Four?=

This are selected quotes from [|a LinkedIn discussion] in the History and Philosophy of Science Group, with added illustrations. Chemical Engineer || Do you consider a number, for example "4" to be different depending on the class - counting, integer, real, complex, etc. or is a number a number?
 * [[image:Tramonte.jpg align="left"]][|Tony Tramonte]


 * For example:
 * 1, 2, 3, 4...
 * ...-2, -1, 0, 1 2, 3, 4...
 * 4 as a real number
 * 4 + 0i
 * 4 as a cardinal number
 * 4 as an ordinal number ||  ||