27,998 research outputs found

    Transfinite inductions producing coanalytic sets

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    A. Miller proved the consistent existence of a coanalytic two-point set, Hamel basis and MAD family. In these cases the classical transfinite induction can be modified to produce a coanalytic set. We generalize his result formulating a condition which can be easily applied in such situations. We reprove the classical results and as a new application we show that in V=LV=L there exists an uncountable coanalytic subset of the plane that intersects every C1C^1 curve in a countable set.Comment: preliminary versio

    Exploring Ericksonian trance inductions

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    The Absolute and Relative Pessimistic Inductions

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    The absolute pessimistic induction states that earlier theories, although successful, were abandoned, so current theories, although successful, will also be abandoned. By contrast, the relative pessimistic induction states that earlier theories, although superior to their predecessors, were discarded, so current theories, although superior to earlier theories, will also be discarded. Some pessimists would have us believe that the relative pessimistic induction avoids empirical progressivism. I argue, however, that it has the same problem as the absolute pessimistic induction, viz., either its premise is implausible or its conclusion does not probably follow from its premise

    The Anti-Induction for Scientific Realism

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    In contemporary philosophy of science, the no-miracles argument and the pessimistic induction are regarded as the strongest arguments for and against scientific realism, respectively. In this paper, I construct a new argument for scientific realism which I call the anti-induction for scientific realism. It holds that, since past theories were false, present theories are true. I provide an example from the history of science to show that anti-inductions sometimes work in science. The anti-induction for scientific realism has several advantages over the no-miracles argument as a positive argument for scientific realism

    Evaluating site induction practice efficiency and effectiveness:an organisational case study

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    The style of induction presentation and other processes, irrespective of duration, immediately establishes the context and attitude of the construction site team and is where initial behavioural standards are established. A case study within a large contractor investigates site induction activities in practice to better understand the operational demands on time for those involved in managing site inductions and the impact of this activity on safety behaviour on site. The research method adopted was a desk-based review of company policy through document analysis, observations of site induction practice, operations and semi structured interviews. Trade-offs between time losses/benefits, safety in practice, technology implementation and their impact on administrative processes are examined. It is argued that the use of observations has allowed the identification of the actual time commitment in practice. The principal contractor's allocated time for providing and undertaking site induction activities was underestimated by 16% to 20%. There is potential to save time through exploitation of existing and new technology solutions more fully. However, those with an H&S leadership role have indicated difficulties in keeping up with the pace of change in technology development for this purpose

    Vortex trapping and expulsion in thin-film YBCO strips

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    A scanning SQUID microscope was used to image vortex trapping as a function of the magnetic induction during cooling in thin-film YBCO strips for strip widths W from 2 to 50 um. We found that vortices were excluded from the strips when the induction Ba was below a critical induction Bc. We present a simple model for the vortex exclusion process which takes into account the vortex - antivortex pair production energy as well as the vortex Meissner and self-energies. This model predicts that the real density n of trapped vortices is given by n=(Ba-BK)/Phi0 with BK = 1.65Phi0/W^2 and Phi0 = h/2e the superconducting flux quantum. This prediction is in good agreement with our experiments on YBCO, as well as with previous experiments on thin-film strips of niobium. We also report on the positions of the trapped vortices. We found that at low densities the vortices were trapped in a single row near the centers of the strips, with the relative intervortex spacing distribution width decreasing as the vortex density increased, a sign of longitudinal ordering. The critical induction for two rows forming in the 35 um wide strip was (2.89 + 1.91-0.93)Bc, consistent with a numerical prediction

    The Grand Pessimistic Induction

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    After decades of intense debate over the old pessimistic induction (Laudan, 1977; Putnam, 1978), it has now become clear that it has at least the following four problems. First, it overlooks the fact that present theories are more successful than past theories. Second, it commits the fallacy of biased statistics. Third, it erroneously groups together past theories from different fields of science. Four, it misses the fact that some theoretical components of past theories were preserved. I argue that these four problems entitle us to construct what I call the grand pessimistic induction that since the old pessimistic induction has infinitely many hidden problems, the new pessimistic induction (Stanford, 2006) also has infinitely many hidden problems

    Scientific Antirealists Have Set Fire to Their Own Houses

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    Scientific antirealists run the argument from underconsideration against scientific realism. I argue that the argument from underconsideration backfires on antirealists’ positive philosophical theories, such as the contextual theory of explanation (van Fraassen, 1980), the English model of rationality (van Fraassen, 1989), the evolutionary explanation of the success of science (Wray, 2008; 2012), and explanatory idealism (Khalifa, 2013). Antirealists strengthen the argument from underconsideration with the pessimistic induction against current scientific theories. In response, I construct a pessimistic induction against antirealists that since antirealists generated problematic philosophical theories in the past, they must be generating problematic philosophical theories now
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