Full Idea
If we accept the Barcan and converse Barcan schemas, this leads to surprising ontological consequences. Wittgenstein might have fathered something, so, by the Barcan schema, there is something that Wittgenstein might have fathered.
Gist of Idea
The Barcan schema implies if X might have fathered something, there is something X might have fathered
Source
Theodore Sider (Writing the Book of the World [2011], 11.9)
Book Reference
Sider,Theodore: 'Writing the Book of the World' [OUP 2011], p.258
A Reaction
[He cites Tim Williamson for this line of thought] I was liking the Barcan picture, by now I am backing away fast. They cannot be serious!