Summary The object of this study is to analyse certain aspects of the debate between David Brewster and William Whewell concerning the probability of extra-terrestrial life, in order to illustrate the nature, constitution and condition of natural theology in the decades immediately preceding the publication in 1859 of Charles Darwin's Origin of species. The argument is directed against a stylised picture of natural theology which has been drawn from a backward projection of the Darwinian antithesis between natural selection and certain (...) forms of the design argument. Contrary to the popular image of natural theology as an essentially static, autonomous and monolithic set of presuppositions about the existence of design in nature, the paper underlines the existence of a fundamental divergence of strategies within natural theology, a divergence that, in the case of Brewster and Whewell, can be correlated with the religious cultures to which they most closely belonged. The fact that, in the plurality of worlds debate, their respective positions became mutually exclusive suggests that the fragmented and disordered state of natural theology, only too apparent before the Darwinian impact, was occasioned as much by the ulterior problem of rationalising the excessive space of the astronomers and the excessive time of the geologists as it was by any principle of the uniformity of nature in the biological sphere. The argument is substantiated with particular reference to the breakdown in communication as Brewster and Whewell developed conflicting strategies to expose the ?development hypothesis? that had appeared in Vestiges. Their altercation also reveals a certain conflict of status concerning the conclusions of astronomy and geology which, in turn, suggests that tensions between the physical and life sciences were not peculiar to the period following the publication of Darwin's theory. (shrink)