Formal versus self-organised knowledge systems: A network approach

► Complex network analysis of the Principia Mathematica of B. Russell. ► We find that the network is scale-free and displays small-world properties. ► Comparison with other directed acyclic graphs: a citation network and a stochastic model. ► Application of phylogenetic techniques to the study of causal networks. ► Highlight of a possible preferential attachment emerging in knowledge webs.