I propose to model imagination as a ceteris paribus modal operator: a variably strict world quantifier in a modal framework including both possible and so-called non-normal or impossible worlds. The latter secure lack of closure under classical logical consequence for the relevant mental states, while the variability of strictness captures how the agent imports information from actuality in the imagined non-actual scenarios. The proposed formal semantics models how a conceiving agent can imagine inconsistencies. I also discuss how similarity may work when impossible worlds are around.