Full Idea
In 1846 De Morgan introduced the enormously influential notion of a possibly arbitrary and stipulated 'universe of discourse'. It replaced Boole's original - and metaphysically a bit suspect - universe of 'all things'.
Gist of Idea
De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things'
Source
report of Augustus De Morgan (works [1846]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1
Book Reference
Walicki,Michal: 'Introduction to Mathematical Logic' [World Scientific 2012], p.20
A Reaction
This not only brings formal logic under control, but also reflects normal talk, because there is always an explicit or implicit domain of discourse when we talk. Of virtually any conversation, you can say what it is 'about'.