Originally published in 1969, this book challenges the view among many 20^th Century philosophers that no cogent arguments could be found capable of providing support for the normative pronouncements of practical morality. The book asserts that this conclusion is mistaken and the result of basic deficiencies endemic in the logical structure of traditional ethics. The volume develops an argument whose logical structure is quite different from the ways of reasoning that have dominated the history of Western ethics and which allows answers to such primary questions of practical morality such as ‘How ought we as moral beings to act?’