Mathematics is a human activity. This observation provides a basis for examining mathematical knowledge, or, more appropriately, mathematical epistemology. In so doing, the constructive act of discovery can be separated from reconstruction required for the communication of the discovery. The key to a fuller understanding of mathematics lies in broadening the scope of the philosophy of mathematics to take into account the psychology of mathematical creativity, the logic of discovery. This requires that we examine the nature of proof and its dependence on a dynamic notion of construction. Mathematics is contructed by people. The philosophy of mathematics must rest on analyses of this construction - on the genetic construction of mathematics in the child; on the historical construction of mathematics as a field; and on the day to day ongoing activities of mathematicians.