 Russell’s Principles of Mathematics (1903) contains extended discussions of Russell’s and Burali-Forti’s paradoxes in various forms in the sections 78, 84–85, 101, 301. Russell’s paradox is adapted to show that a propositional function \(\phi\) cannot be a logical subject (i.e., as separated from its argument; it is not saturated in Frege’s terms); otherwise, \(\phi\) would apply to itself, \(\neg \phi(\phi)\) would be a propositional function and it would be possible to reproduce the inconsistency.