 In levels of mechanisms, the relata are behaving mechanisms at higher levels and their components at lower levels. … The interlevel relationship is as follows: X’s Φ-ing is at a lower mechanistic level than Ψ-ing if and only if X’s Φ-ing is a component in the mechanism for S’s Ψ-ing. Lower level components are organized together to form higher-level components. (Craver 2007: 189)