I'm reading Timothy O'Connor's 'Persons & Causes The metaphysics of free will' and the first chapter briefly goes into (though without introduction) the application of modal logic and counterexamples to non-sufficiently refined explications of the Consequence Argument.
Now, I am actually a mathematics and philosophy student so have studied both 'baby first order logic' in maths, and also Peter Smith's intro to formal logic (seen here) http://www.amazon.co.uk/Introduction-Formal-Logic-Peter-Smith/dp/0521008042 and will be working through Hodges and Chiswell's mathematical logic.
What route - or what material - in modal logic do you think is both sufficient for me to tackle the modal arguments in O'Connor yet at the same time be basic enough to progress from my present understanding of first-order / baby logic?
I would also be interested, on a related note, if someone with experience in the mathematics of philosophy could give some recommendations of - roughly - what kind of suitable progression one may take with a set of logical or mathematical philosophical books of their choosing from someone with not any real exposure to mathematical philosophy.
I bought Russell's Principles of Mathematics but I don't really think this is going to be an enjoyable read on the account of both suitability and introductory considerations.