Science for the twenty-first century: from social contract to the scientific core

The article addresses the need, posed by the challenges of sustainable deve lopment and the changing context at the beginning of the twenty-first centu ry, for changes in the method and practice of science. The major challenges for a 'sustainability science' arise from increasing complexity at the ont ological, epistemological, and political levels, calling for an integrated science going far beyond an inter-disciplinary style of research. The requi rement is for the development. adoption, and dissemination of a truly compl ex-systems scientific research model. Complex socio-ecological systems shar e a number of fundamental properties that require changes in scientific met hods, criteria of truth and quality. and conceptual frameworks. These prope rties include non-linearity, plurality of perspectives, emergence of proper ties, self-organisation, multiplicity of scales, and irreducible uncertaint y. Some implications of the analysis are pointed out, in the form of practi cal recommendations. The authors argue for the involvement of both natural and social scientists in the investigation of the necessary steps to develo p a sustainability science.