Nondeterminacy and Population Ethics

This paper synthesizes a general view out of Derek Parfit’s last views on how to avoid the Repugnant Conclusion and presents the general features of a plausible theory of population ethics based on Parfit’s suggestions. The paper argues that a plausible population axiology provides only partial orderings and implies that some outcomes are nondeterminate in their ranking. The paper shows, first, how the combination of what Parfit calls “imprecise equality” and the “Wide Dual Person-Affecting Principle” allows one to avoid both the Continuum Argument and the Improved Mere Addition Paradox. Second, the paper shows how this is enough to in principle also refute Gustaf Arrhenius’s impossibility theorems. Third, the paper suggests that a plausible population axiology must allow for nondeterminacy, that whatever the substance of the axiology is, it can only provide partial orderings of outcomes, and that if we revise Arrhenius’s adequacy conditions these can condition what a satisfactory population axiology looks like. Finally, the paper illustrates how one can apply normative theories that allow for nondeterminacy and also infer formal constraints on the theories in light of the consequences of their application.

Intrasellar Arachnoid Cyst, a Rare Radiological Finding: Report of a Case.

Intrasellar arachnoid cysts are uncommon radiological findings, generally incidental and clinically silent. We present the case of 70 year-old female who was treated of meningitis due to cerebrospinal fluid nasal fistulae. She was diagnosed of intrasellar arachnoid cyst and managed conservatively because no neurologic, hormonal, symptomatic either CSF fistulae appeared during follow-up. The origin of intrasellar arachnoid cysts is unclear; although an incomplete diaphragma sellae through basal arachnoid membrane herniates may be a plausible theory. Conservative treatment is the usual option, but if hormonal, visual or intracranial hypertension symptoms appeared, surgery may be the best therapy. This entity should be in the differential diagnosis of cystic sellar lesions with other benign cysts and tumors as craniopharyngioma.

Time to Conceive: a New Argument for the Possibility of Time Travel

<p>Ordinarily, philosophers arguing for the possibility of time travel restrict themselves to defending time travel against allegations of inconsistency and contradiction. These objections are usually based on particular theories about time and causality. I believe, however, that this way of arguing can be turned on its head. By using the conceivability thesis – that is, the thesis that if something is conceivable, then it is also possible – we can put forward a positive argument for the possibility of time travel, and then consider how this should inform our metaphysical views. I do this by assuming the truth of the conceivability thesis and then presenting a simple piece of time travel fiction. I argue for the conceivability of this story and, in doing so, attempt to show that the time travel journey it describes is logically possible. I then develop this argument by considering other more controversial cases of time travel. I make minor alterations to the original time travel story in order to show that there are a number of different kinds of time travel journeys (including cases of both forwards and backwards time travel) which are conceivable and, therefore, logically possible. Finally, I ask how the conceivability of different types of time travel should affect the metaphysical views we choose to adopt. I argue that since the conceivability of time travel entails the logical possibility of journeys to other times, any plausible theory of time must be able to accommodate such journeys. I also explain how the conceivability of time travel entails the logical possibility of two particularly unusual cases of causation. I argue that the conceivability of instantaneous time travel entails the logical possibility of causation at a distance, and that the conceivability of backwards time travel entails the logical possibility of backwards causation. Any plausible theory of causation must therefore be able to account for the possibility of these two types of causation. I consider one particular theory of causation which does not (namely, that put forward by D.H. Mellor), and then attempt to establish where it goes wrong.</p>

Time to Conceive: a New Argument for the Possibility of Time Travel

<p>Ordinarily, philosophers arguing for the possibility of time travel restrict themselves to defending time travel against allegations of inconsistency and contradiction. These objections are usually based on particular theories about time and causality. I believe, however, that this way of arguing can be turned on its head. By using the conceivability thesis – that is, the thesis that if something is conceivable, then it is also possible – we can put forward a positive argument for the possibility of time travel, and then consider how this should inform our metaphysical views. I do this by assuming the truth of the conceivability thesis and then presenting a simple piece of time travel fiction. I argue for the conceivability of this story and, in doing so, attempt to show that the time travel journey it describes is logically possible. I then develop this argument by considering other more controversial cases of time travel. I make minor alterations to the original time travel story in order to show that there are a number of different kinds of time travel journeys (including cases of both forwards and backwards time travel) which are conceivable and, therefore, logically possible. Finally, I ask how the conceivability of different types of time travel should affect the metaphysical views we choose to adopt. I argue that since the conceivability of time travel entails the logical possibility of journeys to other times, any plausible theory of time must be able to accommodate such journeys. I also explain how the conceivability of time travel entails the logical possibility of two particularly unusual cases of causation. I argue that the conceivability of instantaneous time travel entails the logical possibility of causation at a distance, and that the conceivability of backwards time travel entails the logical possibility of backwards causation. Any plausible theory of causation must therefore be able to account for the possibility of these two types of causation. I consider one particular theory of causation which does not (namely, that put forward by D.H. Mellor), and then attempt to establish where it goes wrong.</p>

Explicit Import Revisited: A Critical Appraisal of Explicatures

The main goal of this paper is to argue that the way explicitly communicated content is approached in leading pragmatic theories is flawed, since it is posited that explicature generation involves pragmatic enrichment of the decoded logical form of the utterance to full propositionality. This kind of enhancement postulated to underlie explicature generation appears to be theoretically inadequate and not to correspond to the psychological reality of utterance interpretation. Drawing on earlier critique of extant pragmatic positions on explicatures, mainly by Borg (2016) and Jary (2016), I add further arguments against modelling explicitly communicated import in the way leading verbal communication frameworks do. It is emphasized that the cognitively plausible theory of communicated meaning is compromised at the cost of theory-internal concerns.

Religion and the Constitution: A Response to Luke Beck’s Safeguard against Religious Intolerance Theory of Section 116

This article critiques Luke Beck’s ‘safeguard against religious intolerance’ theory of section 116 of the Constitution. We argue that a plausible theory of section 116 must be able to account for the fact that, at Federation, Australia was an overwhelmingly Christian nation, which was opposed to the establishment of any religion but was not ‘secular’, and also for the fact that Australian society has become less religious but with many surviving remnants of the enmeshing of religion and the government. We argue that, consistent with the traditional understanding, section 116 has a federal purpose, being designed to distribute power to legislate in relation to religion throughout the Australian federation. Section 116 can also be seen as promoting religious pluralism, enabling interactions between religion and government. Beck’s theory, and its separationist implications, fails to adequately take these factors into account.

Prudential Language and Context (I)

This chapter examines evaluative prudential language (good for etc.) and directive prudential language (ought, must, needs etc.) and argues for forms of contextualism about each of these types of language. In the case of ‘good for’ talk, it shows how recent work by Steve Finlay (2014) on the context-sensitivity of ‘good’ supplies a plausible theory of ‘good for’. It then moves on ‘needs’ talk, showing how work on deontic modals from, and inspired by, Angelika Kratzer (1977) can be applied in a way that illuminates how ‘needs’, and the like, function in prudential contexts.

Temporal stimulus segmentation by reinforcement learning in populations of spiking neurons

Learning to detect, identify or select stimuli is an essential requirement of many behavioral tasks. In real life situations, relevant and non-relevant stimuli are often embedded in a continuous sensory stream, presumably represented by different segments of neural activity. Here, we introduce a neural circuit model that can learn to identify action-relevant stimuli embedded in a spatio-temporal stream of spike trains, while learning to ignore stimuli that are not behaviorally relevant. The model uses a biologically plausible plasticity rule and learns from the reinforcement of correct decisions taken at the right time. Learning is fully online; it is successful for a wide spectrum of stimulus-encoding strategies; it scales well with population size; and can segment cortical spike patterns recorded from behaving animals. Altogether, these results provide a biologically plausible theory of reinforcement learning in the absence of prior information on the relevance and timing of input stimuli.

Logical Conventionalism

This chapter argues that logical truth, validity, and necessity in any language can be fully explained in terms of the language’s linguistic conventions. More particularly, it is demonstrated that unrestricted logical inferentialism is a version of logical conventionalism by arguing for conventionalism in detail and answering various objections involving the role of metasemantic principles and semantic completeness in the conventionalist argument. The chapter then discusses how this account relates to the deflationist accounts offered by Field and others, before turning to the metaphysics and normativity of logic, which it discusses on conventionalist grounds. Overall, this chapter shows that conventionalism leads to a naturalistically acceptable and philosophically plausible theory of logic.

A user’s view of the validity of acceptability judgments as evidence for syntactic theories

The primary goal of this chapter is to discuss the validity of acceptability judgments as a data type. The author’s view is that acceptability judgments have most, if not all, of the hallmarks of a valid data type: syntacticians have a plausible theory of the source of acceptability judgments, a theory of how to leverage judgments for the construction of syntactic theories using experimental logic, and a set of evaluation criteria that are similar to those used for other data types in the broader field of psychology. At an empirical level, acceptability judgments have been shown to be relatively reliable across tasks and participants, to be relatively sensitive, and to be relatively free of theoretical bias. Therefore the author’s view is that acceptability judgments are at least as valid as other data types that are used in the broader field of language science.