Scaffold: A Causal Concept for Evolutionary Explanations

The concept of scaffold is widespread in science and increasingly common in evolutionary biology. While this concept figures in causal explanations, it is not clear what scaffolds are and what role they play in those explanations. Here we present evolutionary scaffolding explanation as a distinct type of explanatory strategy, distinguishing it from other types of evolutionary explanation. By doing so, we clarify the meaning of "scaffold" as a causal concept and its potential contribution to accounts of evolutionary novelty and major transitions.