FIGURE 2.1 Preformationism A seventeenth-century drawing of a preformed being inside a sperm. This drawing was based on the claim of committed preformationists that when they looked at samples of semen under the newly invented microscope, they could actually see a tiny figure curled up inside the head of the sperm. They believed that the miniature person would enlarge after entering an egg. As this drawing illustrates, we must always take care not to let our cherished preconceptions so dominate our thinking that we see what we want to see—not what is really there. (From Moore & Persaud, 1993, p. 7)
MARY EVANS PICTURE LIBRARY/ALAMY