R. K. Meyer once gave precise form to the question of whether relevant implication can be defined in any modal system, and his answer was `no'. In the present paper, we extend S4, first with ...

The first section of the paper establishes the minimal properties of so-called consequential implication and shows that they are satisfied by at least two different operators of decreasing strength ...

Solutions are available by request for course instructors and the self-taught. These documents are intended for the spring 2024 version of PHI 201, Introductory Logic. However, they will be fine-tuned ...