Fred Sommers

" Vice and virtue in everyday life is a bestseller in college ethics because students find the readings both personally engaging and intellectually challenging. Under the guidance of classical and modern writers on morality, students using this textbook come to grips with moral issues of everyday life. They discover that some currently fashionable approaches to morality, such as egoism and relativism, have long histories. They also become aquainted with the debates and criticisms of various moral doctrines, learning central ethical theories and methods for reasoning about moral issues in the process." -- Back cover.

Modern thinkers regard logic as a purely formal discipline like number theory, and not to be confused with any empirical discipline such as cognitive psychology, which may seek to characterize how people actually reason. Opposed to this is the traditional view that even a formal logic can be cognitively veridical – descriptive of procedures people actually follow in arriving at their deductive judgments (logic as Laws of Thought). In a cognitively veridical logic, any formal proof that a deductive judgment, intuitively arrived at, is valid should ideally conform to the method the reasoning subject has used to arrive at that judgment. More specifically, it should reveal the actual reckoning process that the reasoning subject more or less consciously carries out when they make a deductive inference. That the common logical words used in everyday reasoning – words such as 'and', 'if,''some', 'is''not,' and 'all'– have fixed positive and negative charges has escaped the notice of modern logic. The present paper shows how, by unconsciously recognizing 'not' and 'all' as 'minus-words', while recognizing 'and', 'some', and 'is' as 'plus words', a child can intuitively reckon, for example, 'not (−) all (−) dogs are (+) friendly' as equivalent to 'some (+) dogs aren't (−) friendly': −(−D+F) = +D−F.