Hume asserted that all knowledge comes from the senses, and then gave away the ballgame by excepting abstract propositions, which he called "relations of ideas".

As an abstract proposition, that is logical.

He hadn't expected understanding so quickly, and he doubted the boy was sophisticated enough to offer a deliberate lie about an abstract proposition.

Nor need a man have a vicious subjectiveness because he deals in abstract propositions.

The mere abstract proposition, 'This is a man dying' floated before him in an unemotional way.

As an abstract proposition of course they can die.

In Allan's usage, sociological theory consists of abstract and testable propositions about society.

This is unobjectionable as an abstract proposition and a starting principle.

The result of instantiating P in an abstract proposition is called an instance of the proposition.