Stephen Downes

I'm not sure how long this book chapter (31 page PDF) will be available online, but if you're interested in modality (this study of necessity, actuality and possibility) then you'll definitely enjoy this review that begins with Kant and runs through to Quine, Barcan Marcus, Kripke and Lewis. Ah, happy memories. Seriously, if you're interested in logic, language and meaning, this chapter outlines in a lucid and accesible way some of the core ideas in the field. Via Philosophical Progress.