This lecture treats issues fundamental to the entire course, namely, the nature of causation and our ability to identify it accurately. A crucial point of contact between science and religion is the question of the extent of God’s involvement in the running of the natural world. Theologians across time and denominations disagree widely on this point. Medieval theologians and natural philosophers, however, favored naturalistic explanations whenever possible, rather than recourse to divine intervention. The subject of miracles focused the issue, and the need to discern true miracles from superficially similar human, natural, or demonic marvels required scientific investigation of natural causes and, thus, instances a co-development of science and theology. Very importantly, one’s views of the state of the spiritual world influence and form one’s views toward the natural world and science.