A causal approach to biological information is outlined. There are two aspects to this approach: information as determining a choice between a set of alternative objects, and information as determining the construction of a single object. The first aspect has been developed in earlier work to yield a quantitative measure of biological information that can be used to analyse biological networks. This paper explores the prospects for a measure based on the second aspect, and suggests some applications for such a measure. These two aspects are not suggested to exhaust all the facets of biological information.