This is an introductory textbook of philosophy meant to enable group work in a large lecture. It has many questionnaires and materials for controlled discussions, to facilitate disgnoses of the reasons for disagreements about cases. contents: Certainty and doubt -- Sources of conviction -- Rationalism -- Rationalism versus relativism in morals -- Induction and deduction -- The retreat from certainty -- Utilitarianism -- Kantian ethics -- Empiricism -- Beyond empiricism -- Objectivity -- Materialism and dualism -- Morality for naturalists -- (...) Deep illusions -- Realism. (shrink)