The astronomical discussion between Adam and Raphael reflects the scientific debate that existed in England in the seventeenth century. The discoveries and theories of Copernicus, Kepler, and Galileo were well known throughout England and Europe, but the ideas were also hotly debated. Milton, who had read extensively on the subjects and may even have met Galileo, nonetheless chooses to sidestep the issues in Paradise Lost. Adam and Raphael present varying viewpoints but do not reach a conclusion. Rather Raphael ends the discussion by saying that God left the questions concerning the heavens open to dispute, "perhaps to move / His laughter" (77–78). He adds that Adam should be "lowly wise" (169) and "Dream not of other worlds" (175).
Even though Milton chooses not to reach a conclusion on Adam's questions and ends the debate with homiletic advice from Raphael, it would be misleading to assume that either Milton or Raphael intends to discourage questions about the universe. Milton's interest in science is well established, and Raphael seems pleased with the questions that Adam asks. It was commonplace in the Restoration period to refer to nature as God's Book of Works, which was entirely compatible with God's Book of Words (the Bible). So questions about nature and the heavens were not considered presumptuous, though they could lead to incorrect, even evil, conclusions. Therefore, Adam, in opening up the abstruse topic of the geocentric / heliocentric universe is advised to stick to more down-to-earth queries — not to avoid questions at all.
