Recent catastrophes in environmental management, such as population collapses in oceanic fisheries, have led environmental activists and scholars to invoke the precautionary principle (PP). In its strong form, PP demands that no human-initiated change in an ecosystem be permitted unless it is certain it will do no harm; while, in its weak form, PP holds that if an action might be environmentally harmful, regulators may, on best evidence, limit human activities to avoid damaging ecosystem perturbations. Implementing PP, however, presents epistemological, logical and practical difficulties. This paper compares the function of PP to that of the Biblical Wisdom literature in encouraging ecological prudence, and argues that PP should be replaced by a series of guiding concepts, dealing with the limitations of ecological knowledge and the flaws in human character most likely to result in environmental disaster. The environmental cases analysed are from oceanic fisheries management.