William of Ockham presents the same combination as Scotus, asserting that causal connections are in some way necessary, while undermining the supposed absoluteness of the necessity. Causal connection is such that it can in principle be inferred from a single observation, “since there is no reason why one heat should be more calefactive than another.” But in practice, if we observe that administering a certain kind of herb results in a reduction of fever, we cannot be sure what it is in the herb that effects the cure.51
