Abstract
In the topic-sensitive theory of the logic of imagination due to Berto (2018a), the topic of
the imaginative output must be contained within the imaginative input. That is, imaginative
episodes can never expand what they are about. We argue, with Badura (2021), that this
constraint is implausible from a psychological point of view, and it wrongly predicts the
falsehood of true reports of imagination. Thus the constraint should be relaxed; but how?
A number of direct approaches to relaxing the controversial content-inclusion constraint
are explored in this paper. The core idea is to consider adding an expansion operator to
the mereology of topics. The logic that results depends on the formal constraints placed
on topic expansion, the choice of which are subject to philosophical dispute. The rst
semantics we explore is a topological approach using a closure operator, and we show that
the resulting logic is the same as Berto's own system. The second approach uses an inclusive
and monotone increasing operator, and we give a sound and complete axiomatisation for
its logic. The third approach uses an inclusive and additive operator, and we show that
the associated logic is strictly weaker than the previous two systems, and additivity is not
de nable in the language. The latter result suggests that involved techniques or a more
expressive language is required for a complete axiomatization of the system, which is left
as an open question. All three systems are simple tweaks on Berto's system in that the
language remains propositional, and the underlying theory of topics is unchanged.