Abduction is or subsumes a process of inference. It entertains possible hypotheses and it chooses hypotheses for further scrutiny. There is a large literature on various aspects of non-symbolic, subconscious abduction. There is also a very active research community working on the symbolic (logical) characterisation of abduction, which typically treats it as a form of hypothetico-deductive reasoning. In this paper we start to bridge the gap between the symbolic and sub-symbolic approaches to abduction. We are interested in benefiting from developments (...) made by each community. In particular, we are interested in the ability of non-symbolic systems (neural networks) to learn from experience using efficient algorithms and to perform massively parallel computations of alternative abductive explanations. At the same time, we would like to benefit from the rigour and semantic clarity of symbolic logic. We present two approaches to dealing with abduction in neural networks. One of them uses Connectionist Modal Logic and a translation of Horn clauses into modal clauses to come up with a neural network ensemble that computes abductive explanations in a top-down fashion. The other combines neural-symbolic systems and abductive logic programming and proposes a neural architecture which performs a more systematic, bottom-up computation of alternative abductive explanations. Both approaches employ standard neural network architectures which are already known to be highly effective in practical learning applications. Differently from previous work in the area, our aim is to promote the integration of reasoning and learning in a way that the neural network provides the machinery for cognitive computation, inductive learning and hypothetical reasoning, while logic provides the rigour and explanation capability to the systems, facilitating the interaction with the outside world. Although it is left as future work to determine whether the structure of one of the proposed approaches is more amenable to learning than the other, we hope to have contributed to the development of the area by approaching it from the perspective of symbolic and sub-symbolic integration. (shrink)

The political philosophy of health care has been characterized by considerable conceptual inflation in recent years. First, the concept of health that lies at its core has come to encompass ever-increasing aspects of individuals’ existences. And second, the emergence of the public health perspective has increased the range of resources relevant to health equity. This expansion has not been without cost. The decision to include more rather than less within the ambit of "health" is ultimately a moral/political rather than an (...) ontological or metaphysical one, and there are several ethical reasons to define the scope of theories of distributive justice in health narrowly. (shrink)

Plotinus maintains that our intellect is always thinking. This is due to his view that our intellect remains in the intelligible world and shares a natural kinship with the hypostasis Intellect, whose being and activity consists in eternal contemplation of the Forms. Moreover, Plotinus maintains that although our intellect is always thinking we do not always apprehend our thoughts. This is due to his view that “we“ descend into the sensible world while our intellect remains in the intelligible world. Furthermore, (...) Plotinus maintains that it is only when logoi unfold the content of our thoughts into the imagination that we apprehend them. This is due to a complex account between, on the one hand, the relationship between intellect and discursive reasoning, and on the other hand, the relationship between discursive reasoning and language. Plotinus tells this story with remarkable brevity in Ennead 4.3.30. In this paper I explain the role the imagination plays in the apprehension of thoughts through a close analysis of this treatise in connection with Ennead 1.4.10. (shrink)

The publish-or-perish paradigm is a prevailing facet of science. We apply game theory to show that, under rather weak assumptions, this publication scenario takes the form of a prisoner’s dilemma, which constitutes a substantial obstacle to beneficial delayed publication of more complete results. One way of avoiding this obstacle while allowing researchers to establish priority of discoveries would be an updated “pli cacheté”, a sealed envelope concept from the 1700s. We describe institutional rules that could additionally favour high-quality work and (...) publications and provide examples of such policies that are already in place. Our analysis should be extended to other publication scenarios and the role of other stakeholders such as scientific journals or sponsors. (shrink)