The source of order in living systems has been the key question at the boundary of biology and philosophy since the eighteenth century. Today it is widely believed that living systems differ from non-living because they are driven by information, much of which has accumulated during evolution, and much of which is genetically transmitted. But there is at present no specifically biological measure of information that can underpin this vision. In this lecture, I attempt to fill this gap by grounding the idea of biological information in contemporary philosophical work on the nature of causation. This approach to biological information is inspired by the early theoretical insights of the co-discoverer of the structure of DNA, Francis Crick, but is general enough to capture the informational contribution of environmental factors in development, epigenetic information, and the emergence of new information in self-organizing processes.