How do ideas evolve? Can one speak of scientific progress when there is more than one pathway of intellectual evolution in which different ideas emerge and flow in different directions? Is the history of economic analysis a compilation of a number of intellectual pathways? This essay argues that it is possible to understand the course of history as a number of overlapping, divergent, and endlessly changing pathways. Such pathways operate in different fashions. They sometimes lead to more coherent and high (...) levels of understanding. And sometimes they delay or obstruct advancement in intellectual history. In both cases, outcomes are unpredictable and multi-directional. (shrink)