ABSTRACT
We analyse two specific types of idealisations, namely limit idealisations and factor exclusions. Limit idealisations push a certain property to an extreme; a factor exclusion omits a certain factor entirely. To pave the ground for a discussion of limit idealisation, we introduce limits and review some of their important properties. We then present a definition of a limit idealisation and examine how surrogative reasoning with limits works, which will depend crucially on whether limits are regular or singular. We then discuss factor exclusions. Excluded properties can later be reintroduced into a model, which leads to the inclusion scheme. The inclusion scheme can be interpreted in at least two different ways, leading to Galilean idealisations and minimalist idealisations.
