We address a recent proposal concerning surplus structure due to Nguyen et al. [Why Surplus Structure is Not Superfluous. Br. J. Phi. Sci. Forthcoming.] We argue that the sense of surplus structure captured by their formal criterion is importantly different from---and in a sense, opposite to---another sense of surplus structure used by philosophers. We argue that minimizing structure in one sense is generally incompatible with minimizing structure in the other sense. We then show how these distinctions bear on Nguyen et al.s arguments about Yang-Mills theory and on the hole argument.
The celu of the philosophical literature on the hole argument is the 1987 paper by Earman & Norton [What Price Space-time Substantivalism? The Hole Story Br. J. Phil. Sci.]. This paper has a well-known back-story, concerning work by Stachel and Norto
n on Einsteins thinking in the years 1913-15. Less well-known is a connection between the hole argument and Earmans work on Leibniz in the 1970s and 1980s, which in turn can be traced to an argument first presented in 1975 by Howard Stein. Remarkably, this thread originates with a misattribution: the argument Earman attributes to Stein, which ultimately morphs into the hole argument, was not the argument Stein gave. The present paper explores this episode and presents some reflections on how it bears on the subsequent literature.
Typicality arguments attempt to use the Copernican Principle to draw conclusions about the cosmos and presently unknown conscious beings within it. The most notorious is the Doomsday Argument, which purports to constrain humanitys future from its cur
rent lifespan alone. These arguments rest on a likelihood calculation that penalizes models in proportion to the number of distinguishable observers. I argue that such reasoning leads to solipsism, the belief that one is the only being in the world, and is therefore unacceptable. Using variants of the Sleeping Beauty thought experiment as a guide, I present a framework for evaluating observations in a large cosmos: Fine Graining with Auxiliary Indexicals (FGAI). FGAI requires the construction of specific models of physical outcomes and observations. Valid typicality arguments then emerge from the combinatorial properties of third-person physical microhypotheses. Indexical (observer-relative) facts do not directly constrain physical theories. Instead they serve to weight different provisional evaluations of credence. These weights define a probabilistic reference class of locations. As indexical knowledge changes, the weights shift. I show that the self-applied Doomsday Argument fails in FGAI, even though it can work for an external observer. I also discuss how FGAI could handle observations in large universes with Boltzmann brains.
We introduce the concept of self-healing in the field of complex networks. Obvious applications range from infrastructural to technological networks. By exploiting the presence of redundant links in recovering the connectivity of the system, we intro
duce self-healing capabilities through the application of distributed communication protocols granting the smartness of the system. We analyze the interplay between redundancies and smart reconfiguration protocols in improving the resilience of networked infrastructures to multiple failures; in particular, we measure the fraction of nodes still served for increasing levels of network damages. We study the effects of different connectivity patterns (planar square-grids, small-world, scale-free networks) on the healing performances. The study of small-world topologies shows us that the introduction of some long-range connections in the planar grids greatly enhances the resilience to multiple failures giving results comparable to the most resilient (but less realistic) scale-free structures.
A general sketch of how the problem of space dimensionality depends on Anthropic arguments is presented. A new argument in favor of a stable scenario for space dimensionality for a time scale longer than that required for the existence of human or an
other kind of highly-evolved life on Earth is proposed.
The AMR (Abstract Meaning Representation) formalism for representing meaning of natural language sentences was not designed to deal with scope and quantifiers. By extending AMR with indices for contexts and formulating constraints on these contexts,
a formalism is derived that makes correct prediction for inferences involving negation and bound variables. The attractive core predicate-argument structure of AMR is preserved. The resulting framework is similar to that of Discourse Representation Theory.