11 research outputs found
Nominal tense logic and other sorted intensional frameworks
This thesis introduces of a system of tense logic called nominal tense logic (NTL), and
several extensions. Its primary aim is to establish that these systems are logically interesting,
and can provide useful models of natural language tense, temporal reference, and
their interaction.
Languages of nominal tense logic are a simple augmentation of Priorean tense logic.
They add to the familiar Priorean languages a new sort of atomic symbol, nominals. Like
propositional variables, nominals are atomic sentences and may be freely combined with
other wffs using the usual connectives. When interpreting these languages we handle the
Priorean components standardly, but insist that nominals must be true at one and only
one time. We can think of nominals as naming this time.
Logically, the change increases the expressive power of tensed languages. There are
certain intuitions about the flow of time, such as irreflexivity, that cannot be expressed
in Priorean languages; with nominals they can. The effects of this increase in expressive
power on the usual model theoretic results for tensed languages discussed, and completeness
and decidability results for several temporally interesting classes of frames are
given. Various extensions of the basic system are also investigated and similar results
are proved. In the final chapter a brief treatment of similarly referential interval based
logics is presented.
As far as natural language semantics is concerned, the change is an important one. A
familiar criticism of Priorean tense logic is that as it lacks any mechanism for temporal
reference, it cannot provide realistic models of natural language temporal usage. Natural
language tense is at least partly about referring to times, and nowadays the deictic and
anaphoric properties of tense are a focus of research. The thesis presents a uniform treatment
of certain temporally referring expressions such as indexicals, and simple discourse
phenomena
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Moral Luck in Medical Ethics and Practical Politics
Typically we maintain two incompatible standards towards right action and good character, and the tension between these polarities creates the paradox of moral luck. In practice we regard actions as right or wrong, and character as good or bad, partly according to what happens as a result of the agent's decision. Yet we also think that people should not be held responsible for matters beyond their control.
This split underpins Kant's assertion that only the good will is securely good, that its goodness is impervious to outcome ill-luck. Some commentators, such as Martha Nussbaum and to some extent Bernard Williams, think that this simply writes off the paradox. Williams asserts that the paradox is insoluble, and that its inescapability threatens the notion of agent responsibility. In contrast Thomas Nagel argues that agents' most cherished projects may be indeed be subject to luck, but that does not mean that their deepest motivations are moral. This, I suggest, is one of several means whereby we might limit the effect of the paradox without denying that the tension exists. But I also argue that it is wrong to accuse Kant of ignoring the paradox.
Ethical consequentialists, on the other hand, appear to have no problem with moral luck, because the paradox depends on a dichotomy between the outside world and the locus of moral worth in the individual agent. But this turns out not to be true. The problem of moral luck is not some strange Kantian fixation, but a general dilemma: a variant on what
Nagel terms "the problem of excess objectivity" which cuts across all of ethics and metaphysics.
Retaining a broadly Kantian notion of agent-responsibility, but limiting what agents are responsible for, requires us to delineate the realm of ethics more narrowly than has been done by those who believe that the rational and/or prudential are coterminous with the ethical. This strategy for minimising the paradox's impact is explored in two areas from medical ethics, the allocation of scarce medical resources and informed consent, and two from public policy, secrecy and nuclear deterrence. Throughout, the analysis seeks to test Nagel's maxim that the best we can hope for is to act in such a manner that we would not have to revise our opinion of how we should have acted once the consequences of our actions become apparent