"In an intersting and wide-ranging discussion, Parsons surveys various explanations and justifications provided by mathematicians and philosophers, concluding that ontological features do not play an essential role in the development of ZF, and need not be taken to be part of the literal truth about sets." Philip Bricker, Journal of Symbolic Logic
Modality, morality and belief are among the most controversial topics in philosophy today, and few philosophers have shaped these debates as deeply as Ruth Barcan Marcus. Inspired by her work, a distinguished group of philosophers explore these issues, refine and sharpen arguments and develop new positions on such topics as possible worlds, moral dilemmas, essentialism, and the explantion of actions by beliefs. This state of the art collection honors one of the most rigorous and iconoclastic of philosophical pioneers.