Abstract

The ArgumentThe claim that Jan Swammerdam's empirical research did not support his theory of biological preformation is shown to rest on a notion of evidence narrower than that used by many seventeenth-century natural philosophers. The principles of evidence behind the use of mechanical models are developed. It is then shown that the Cartesian theory of biological reproduction and embryology failed to gain acceptance because it did not meet the evidential requirements of these principles. The problems in this and other mechanistic theories prior to Swammerdam are found to arise from certain difficulties and tensions in the mechanical conception of nature, which Swammerdam's theory is able to resolve. The relation between Swammerdam's empirical research and his theory is examined and shown to satisfy the required notion of evidence.Leibniz' puzzling appeals to Swammerdam's research in support of his metaphysical doctrine of the spontaneous development of individual substances are then examined and shown to fall within the parameters of the notion of evidence.