Chapters 6 and 7 deal with the relationship between affirmative, negative, universal and particular propositions.

By removing it alone, while upholding the other two one may still be able to prove all negative propositions from a contradiction.

The consideration of negative propositions and negative facts introduces further complications.

Owing to these complications, the simplest type of correspondence is impossible when either negative facts or negative propositions are involved.

One can go only so far in proving negative propositions by example.

They denied that truth could be inferred by negative categorical propositions, and would only allow positive ones, and of these only simple ones.

Thus a negative proposition has two causes of truth.

And being of warm blood he had not the phlegm tacitly to negative any proposition by unresponsive inaction.

You're asking me to prove a negative proposition.

It is about time that our intellectual and political leaders proposed this constructive move, instead of wrestling endlessly over negative propositions.