Technical point of order, Lawrence. It wasn't the Middle Ages that saw the collapse of the Greek scientific enterprise along with the entirety of Classical civilization, it was late antiquity. The Middle Ages are what RESULTED from that collapse. It's not really fair to blame medieval people simply for being medieval. Indeed, the "medieval millennium" from c.500-1500AD actually saw Europeans rebuilding the kind of society that could support sustained high-level intellectual endeavour (as epitomised by the medieval invention of the University), then re-learning and rediscovering what had been lost in the collapse of the ancient world. The Renaissance and Enlightenment did not come out of nowhere. They would not have happened if the ground had not been prepared through many centuries of medieval development, quickening and endeavour. If you want to see how knowledge and progress are lost, it behoves that you look not to the way society operates after it has been lost, but to the way society is operating beforehand.