The paper considers the question of when the operator L of necessity in modal logic can be expressed in terms of the operator meaning it is non-contingent that.

In a number of publications A.N. Prior considered the use of what he called ‘metric tense logic’. This is a tense logic in which the past and future operators P and F have an index representing a temporal distance, so that Pnα means that α was true n -much ago, and Fn α means that α will be true n -much hence. The paper investigates the use of metric predicate tense logic in formalising phenomena ormally treated by such devices as (...) multiple indexing or quantification over times. (shrink)

The paper presents an indexical semantics, based on times and worlds, for some of Prior's logics concerned with issues such as foreknowledge and determinism. In that sense Prior's logic of futurity can be presented as a completely standard modal/tense logic.

It is often assumed that the central problem in a medical ethics issue is determining which course of action is morally correct. There are some aspects of ethical issues that will yield to such analysis. However, at the core of important medical moral problems is an irreducible dilemma in which all possible courses of action, including inaction, seem ethically unsatisfactory. When facing these issues ethical behaviour depends upon an individual's understanding and acceptance of this painful dilemma without recourse to external (...) moral authority. (shrink)