Images and ideas: Leeuwenhoek's perception of the spermatozoa.

Abstract

Henry Power, that optimistic devotee of the early microscope, warned in the I 660s that "our best Philosophers will but prove empty Conjecturalists, and their profoundest Speculations herein, but gloss'd outside Fallacies" if they did not exploit such new instruments.' He himself looked to the further confirmation and elucidation of the corpuscular natural philosophy,2 but in the following decades the most consequential revelations of the miscroscope might reasonably have been expected to pertain more specifically to biological generation. No other question in seventeenth-century and eighteenth-century science was more laden with philosophical and religious overtones, for it asked if and how a despiritualized, mechanistic nature could engender the purposeful complexity of living organisms, including man. As such exceptional observers as Marcello Malpighi, Jan Swammerdam, and Antoni van Leeuwenhoek probed various instances of generation with their microscopes, the community of the learned, the "Republic of Letters," waited for some decisive new testimony. For Leeuwenhoek, whose microscopes were the finest before the nineteenth century and whose persistence pushed early microscopy to its furthest limits, the generation of living things became an enduring preoccupation, and his observations and conclusions unsettled a recently recast consensus. However, these observations also revealed how little as yet though Leibniz, for one, was convinced otherwise3 the microscope could offer philosophy and how much, rather, it ultimately supported a resurgent skepticism. Probing the limits of what could then be observed in the minute mechanisms of living things, Leeuwenhoek's instruments seemed in the end to reaffirm that the fundamental processes of generation would remain unknown.