Single Idea 13719

[catalogued under 10. Modality / E. Possible worlds / 3. Transworld Objects / e. Possible Objects]

Full Idea

A problem with the Barcan Formula is it might be possible for there to exist a ghost, even though there in fact exists nothing that could be a ghost. There could have existed some 'extra' thing which could be a ghost.

Gist of Idea

Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost

Source

Theodore Sider (Logic for Philosophy [2010], 9.5.2)

Book Reference

Sider,Theodore: 'Logic for Philosophy' [OUP 2010], p.239


A Reaction

Thus when we make modal claims, do they only refer to what actually exists, or is specified in our initial domain? Can a claim enlarge the domain? Are domains 'variable'? Simple claims about what might have existed seem to be a problem.