 Popper’s argues against the propriety of large-scale planning of social structures on the basis of this demonstration of the logical shortcomings of historicism. It is, he argues, theoretically as well as practically misguided, because, again, part of what we are planning for is our future knowledge, and our future knowledge is not something which we can in principle now possess—we cannot adequately plan for unexpected advances in our future knowledge, or for the effects which such advances will have upon society as a whole. For him, this necessitates the acceptance of historical indeterminism as the only philosophy of history which is commensurate with a proper understanding of the provisional and incomplete nature of human knowledge.