SOURCE: “Frankenstein's Science,” in From Soul to Mind: The Emergence of Psychology from Erasmus Darwin to William James, Yale University Press, 1997, pp. 38-59.

In the following excerpt, Reed examines the essence and impact of Darwin's contribution to the alternative psychological theory referred to as fluid materialism—a belief that the human mind, and indeed life itself, can be understood within the framework of natural science.

… Erasmus Darwin's Zoonomia (the first edition appeared in 1792-94, but many subsequent editions were published all over Europe) launched a true alternative psychology, later popularized in his poem The Temple of Nature (1803). In Zoonomia, Darwin defined ideas as the motions of fibers in our organs of sense, and the pattern of these motions. In an addendum to the text he went so far as to say that the theory that ideas are uniquely mental events and not part of everyday nature is nothing...