  Barlaam and Gregoras were both on the losing side in the Hesychast strife, which raged between c. 1337 and 1351 and revolved around the question of theological method. The winner was Gregory Palamas (1296–1359), famous for his claim that even though God’s substance (ousia) is necessarily concealed to us, we can have direct experience of his activities (energeiai). The first 29 of Palamas’ 150 Chapters attempt to put natural philosophy on a more secure footing by placing facts about the world as a whole—in contrast to particular facts, such as astronomical phenomena—in the same epistemological category as facts about God and Man, which are only knowable through the teaching of the spirit. Thus Palamas expends considerable energy on denouncing the erroneous views of the Greek natural philosophers, Platonists as well as Aristotelians.