1,919 research outputs found

    A Formal Apology for Metaphysics

    Get PDF
    There is an old meta-philosophical worry: very roughly, metaphysical theories have no observational consequences and so the study of metaphysics has no value. The worry has been around in some form since the rise of logical positivism in the early twentieth century but has seen a bit of a renaissance recently. In this paper, I provide an apology for metaphysics in the face of this kind of concern. The core of the argument is this: pure mathematics detaches from science in much the same manner as metaphysics and yet it is valuable nonetheless. The source of value enjoyed by pure mathematics extends to metaphysics as well. Accordingly, if one denies that metaphysics has value, then one is forced to deny that pure mathematics has value. The argument places an added burden on the sceptic of metaphysics. If one truly believes that metaphysics is worthless (as some philosophers do), then one must give up on pure mathematics as well

    What's So Spatial About Time Anyway?

    Get PDF
    Both Skow (2007) and Callender (2008) independently argue that time can be distinguished from space due to the special role it plays in our laws of nature: our laws determine the behaviour of physical systems across time, but not across space. In this work we asses the claim that the laws of nature might provide the basis for distinguishing time from space by looking specifically at the claims of Skow and Callender. We find that there is an obvious reason to be sceptical of the argument Skow submits for distinguishing time from space: Skow fails to pay sufficient attention to the relationship between the dynamical laws and the antecedent conditions required to establish a complete solution from the laws. Callender's more sophisticated argument in favour of distinguishing time from space by virtue of the laws of nature presents a much stronger basis to draw the distinction. We raise, however, the possibility that Callender's account in a certain sense shifts the bump in the carpet: that laws are more 'informative' in the temporal direction seems to call out for an underlying explanation, and whatever this underlying factor is, surely this is the real distinction between time and space

    What's So Spatial About Time Anyway?

    Get PDF
    Skow ([2007]), and much more recently Callender ([2017]), argue that time can be distinguished from space due to the special role it plays in our laws of nature: our laws determine the behaviour of physical systems across time, but not across space. In this work we assess the claim that the laws of nature might provide the basis for distinguishing time from space. We find that there is an obvious reason to be sceptical of the argument Skow submits for distinguishing time from space: Skow fails to pay sufficient attention to the relationship between the dynamical laws and the antecedent conditions required to establish a complete solution from the laws. Callender’s more sophisticated arguments in favour of distinguishing time from space by virtue of the laws of nature presents a much stronger basis to draw the distinction. By developing a radical reading of Callender’s view we propose a novel approach to differentiating time and space that we call temporal perspectivalism. This is the view according to which the difference between time and space is a function of the agentive perspective

    What's So Spatial About Time Anyway?

    Get PDF
    Both Skow (2007) and Callender (2008) independently argue that time can be distinguished from space due to the special role it plays in our laws of nature: our laws determine the behaviour of physical systems across time, but not across space. In this work we asses the claim that the laws of nature might provide the basis for distinguishing time from space by looking specifically at the claims of Skow and Callender. We find that there is an obvious reason to be sceptical of the argument Skow submits for distinguishing time from space: Skow fails to pay sufficient attention to the relationship between the dynamical laws and the antecedent conditions required to establish a complete solution from the laws. Callender's more sophisticated argument in favour of distinguishing time from space by virtue of the laws of nature presents a much stronger basis to draw the distinction. We raise, however, the possibility that Callender's account in a certain sense shifts the bump in the carpet: that laws are more 'informative' in the temporal direction seems to call out for an underlying explanation, and whatever this underlying factor is, surely this is the real distinction between time and space

    Polymère souple pour antenne patch électriquement accordable en bande X : conception et caractérisations

    Get PDF
    In communication systems, smart antennas with large frequency tunability (agility) have been gaining worldwide attention over the past few years due to the proliferation of global wireless communication standards in close proximity to one another. However, conventional solutions use electronic components which induce additional costs and make the system more complicated. Moreover, the electronic devices have moved from rigid to flexible dielectric substrates to reduce the cost and to obtain stretchability and conformability properties.The goal of this thesis is to put together these two topics. The chosen original approach consists of the mechanical reconfiguration of antenna patch printed on a soft membrane substrate with electrostatic actuation in X band, at around 10 GHz. Moreover, a new polymeric substrate was employed in this structure, the polyurethane (PU).Firstly, the technological processes required to realize the antenna patch on the PU substrate were developed. Then, the dielectric properties of polyurethane films were measured on a large frequency band in order to define the antenna patch dimensions using high frequency simulations. Finally, the first antennas patch realized and characterized have a figure of merit Frequency tunability/Voltage higher than the state of the art. Preliminary studies were also carried out to explore various feasible ways for improved the antenna systems performances.Dans le domaine des systèmes communicants, les antennes accordables (agiles) en fréquence suscitent un intérêt croissant en raison de la prolifération des standards de communication sans fils, proches les uns des autres. Toutefois, les solutions traditionnelles sont basées sur des composants actifs qui ont pour effet d’engendrer un surcoût et de complexifier le système. De plus, nous assistons également à une migration de l’électronique sur substrat rigide vers des substrats flexibles pour des raisons de coût et une recherche de souplesse et de conformabilité des systèmes.Cette thèse a pour objectif de lier ces deux thématiques par une approche originale qui consiste en la reconfiguration mécanique d’antenne patch sur substrat membranaire souple par un actionnement électrostatique en bande X, vers 10 GHz. Pour cela, un substrat polymérique innovant pour ce type de structure antennaire est utilisé, le polyuréthane (PU).À cet effet, les procédés technologiques nécessaires à la fabrication des antennes patch sur substrat en PU ont été développés. Ensuite, la caractérisation des propriétés diélectriques de films de polyuréthane sur une large bande de fréquence a été effectuée afin de pouvoir dimensionner le système antennaire à l’aide de simulations hyperfréquence. Enfin, la réalisation et la caractérisation de premiers systèmes antennaires sur membrane en PU ont montré que les figures de mérites Agilité fréquentielle/Tension mesurées sont supérieures à l’état de l’art. Des études préliminaires ont également été effectuées pour explorer différentes voies envisageables en vue d’une amélioration des performances des systèmes antennaires

    Mathematical Explanation: A Pythagorean Proposal

    Get PDF
    • …
    corecore