One popular view of the relationship between science and religion, but also science and the occult, from the Enlightenment on is encompassed by what Bernard Lightman calls the “secularization thesis.” According to this account, science gradually but surely supplanted religion and the occult as the ultimate authority for understanding the natural world. While Berkeley, for instance, is relevant to nineteenth-century epistemologists and philosophers of science, his theory of vision is effectively purged of its theological dimension and absorbed by secular empiricism and scientific naturalism. But the secularization story, as Lightman, among others, has persuasively shown, is in some ways a myth: a scientifically informed natural theology flourished in the nineteenth century, and many of the prominent scientific naturalists of the period were agnostics, not hostile to religion but rather advocating a separation of spheres. Moreover, as I shall argue now, nineteenth-century science opened up new paths into the occult by virtue of its explorations of objects and phenomena that elude the limited register of the bodily senses – the invisible, unseen world surrounding us, whose properties we cannot directly observe and measure, but about which we can make strong, seemingly incontrovertible inferences. Spiritualist claims about ghosts, for instance, suddenly seemed more credible, and hopes about a future life compatible with, and supported by, scientific theories in the fields of optics, thermodynamics, and mathematics.