In mathematics these days, essentially everything is a set. Some knowledge of set theory is necessary part of the background everyone needs for further study of mathematics. It is also possible to study set theory for its own interest--it is a subject with intruiging results anout simple objects. This book starts with material that nobody can do without. There is no end to what can be learned of set theory, but here is a beginning.

    

    The point of this wider-than-normal usage of the term "phenomenalism," according to which even some forms of direct realism deserve to be called phenomenalistic, is to call attention to important continuities of thought between theories often thought to be competitors. Williams's target is not phenomenalism in its classical sense-datum and reductionist form but empiricism generally. Williams examines and rejects the idea that, unless our beliefs are answerable to a "given" element in experience, objective knowledge will be impossible. Groundless Belief was first published in 1977. This second edition contains a new afterword in which Williams places his arguments in the context of some current discussions of coherentism versus the Myth of the Given and explains their relation to subsequent developments in his own epistemological views.