proposition
US /ˌprɑː.pəˈzɪʃ.ən/
UK /ˌprɑː.pəˈzɪʃ.ən/

1.
a statement or assertion that expresses a judgment or opinion
:
•
The scientist presented a new proposition about the origin of the universe.
•
His latest book explores the proposition that art can change society.
2.