Book Review

The Invisible World: Early modern philosophy and the invention of the microscope

N Engl J Med 1996; 334:409February 8, 1996

Article

The Invisible World: Early modern philosophy and the invention of the microscope
By Catherine Wilson. 280 pp. Princeton, N.J., Princeton University Press, 1995. $39.50. ISBN: 0-691-03418-4

At the beginning of the Metaphysics, Aristotle exalts sight above the other senses for its power to lead us to knowledge. Presumably, the more and the better we can see, the more we will know. In this fascinating account of the invisible world opened up by the invention of the microscope, Catherine Wilson suggests that seeing more may not necessarily mean understanding more.

Wilson describes how the early microscopists of the 17th century explored the subvisible structures of animals, plants, insects, and minerals. She faithfully details the microscopical discoveries made by Hooke, Leeuwenhoek, Malpighi, and others. But what is more intriguing is her focus on the way the “invisible world” they revealed changed the “perceptual horizon” of science and philosophy.

What the microscopists saw shaped early modern science. Natural philosophy turned from speculation to empirical observation. As instruments were refined and became more sophisticated, observation could be measured and quantified. A host of previously speculative problems in natural philosophy — spontaneous generation, contagion, the development of the human embryo, the existence of the homunculus, and so forth — became subject to direct observation.

The microscope and its contemporary companion, the telescope, raised the hope that humans could get at the ultimate structure of nature, a hope still nurtured today by instruments that “see” down to the atom and out to the fringes of the universe. But for some people, the microscopists' revelations were unwelcome and disturbing, and they were even denounced as inhibitors of truth. Wilson shows how the uncovering of an invisible world engaged both ontologic and empirical deductions about the nature of the real world.

The microscope provided an antidote to the subjectivity and hyperrationality of natural philosophy. But questions were also raised about the reliability of the knowledge obtained when instruments were interposed between the observer and the object of observation. Was the result a more or less true picture of the natural world?

Wilson's historiography strikes a balance between the theories of discontinuity and paradigm shifts, on the one hand, and the excesses of the “great man” schools, on the other. She sees discoveries as the result of a rich and complex interaction among individual people, the Zeitgeist, and streams of thought from the past. Accepting the microscope as trustworthy was no simple matter of accepting the obvious.

This original, well-documented, and imaginative account of the influence of an instrument we take so much for granted today challenges Aristotle's belief that seeing better necessarily means knowing better. As Wilson concludes, extending the domain of what we can see clearly may only force us “to extract meaning from the optically indeterminate.”

Edmund D. Pellegrino, M.D.
Georgetown University Medical Center, Washington, DC 20007