Ideology is commonly defined along functional, epistemic, and genetic dimensions. This article advances a reasonably unified account that specifies how they connect and locates the mechanisms at work. I frame the account along a recent distinction between anchoring and grounding, endorse an etiological reading of functional explanations, and draw on current work about the epistemology of delusion, looping effects, and structuring causes to explain how ideologies originate, reproduce, and possibly collapse. This eventually allows articulating how the legitimating function of ideologies (...) relates to the constitutive and causal role they play when embedded into the facts they are originally designed to anchor. (shrink)