Can I ever, by my subsequent actions, bring it about that something I on a previous occasion was done from a certain motive rather than from some other one?

Originally published in 1965. This is a textbook of modern deductive logic, designed for beginners but leading further into the heart of the subject than most other books of the kind. The fields covered are the Propositional Calculus, the more elementary parts of the Predicate Calculus, and Syllogistic Logic treated from a modern point of view. In each of the systems discussed the main emphases are on Decision Procedures and Axiomatisation, and the material is presented with as much formal rigour (...) as is compatible with clarity of exposition. The techniques used are not only described but given a theoretical justification. Proofs of Consistency, Completeness and Independence are set out in detail. The fundamental characteristics of the various systems studies, and their relations to each other are established by meta-logical proofs, which are used freely in all sections of the book. Exercises are appended to most of the chapters, and answers are provided. (shrink)

It is not infrequently said that the true justification of moral beliefs lies in theology. I wish here to examine precisely what is meant by this contention, and by what arguments, if any, it can be substantiated. The view I am examining is not that the only valid reason for doing what is right is a theological reason ; as if we could know independently of theology what was right, but required a theological motive to make it reasonable to do (...) it. It is rather that the very fact that it is right is logically dependent on certain facts of a theological nature; or, to express the matter otherwise, that from certain theological propositions it is possible validly to draw certain conclusions in the form of propositions which state what I ought to do, and that this fact is the source of the validity of these latter propositions. This, however, is not yet a sufficiently precise account of the theory in question, since it might cover a number of different contentions, some of which I think may be reasonably maintained, while others, I think, may not. I propose to work towards a clearer formulation by considering certain arguments which have been advanced in order to deny outright the very possibility of arguing validly “from theology to ethics”; for I do believe that these arguments prove something , and rule out certain theories as untenable. (shrink)