Educating for love of wisdom : John Dewey and Simone Weil

The writings of John Dewey (1859-1952) and Simone Weil (1909-1943) were analyzed with a view to answering 3 main questions: What is wisdom? How is wisdom connected to experience? How does one educate for a love of wisdom? Using a dialectical method whereby Dewey (a pragmatist) was critiqued by Weil (a Christian Platonist) and vice versa, commonalities and differences were identified and clarified. For both, wisdom involved the application of thought to specific, concrete problems in order to secure a better way of life. For Weil, wisdom was centered on a love of truth that involved a certain way of applying one's attention to a concrete or theoretical problem. Weil believed that nature was subject to a divine wisdom and that a truly democratic society had supernatural roots. Dewey believed that any attempt to move beyond nature would stunt the growth of wisdom. For him, wisdom could be nourished only by natural streams-even if some ofthem were given a divine designation. For both, wisdom emerged through the discipline of work understood as intelligent activity, a coherent relationship between thinking and acting. Although Weil and Dewey differed on how they distinguished these 2 activities, they both advocated a type of education which involved practical experience and confronted concrete problems. Whereas Dewey viewed each problem optimistically with the hope of solving it, Weil saw wisdom in, contemplating insoluble contradictions. For both, educating for a love of wisdom meant cultivating a student's desire to keep thinking in line with acting-wanting to test ideas in action and striving to make sense of actions observed.

Planar Topological Defects in Unconventional Superconductors

In this work, we consider the properties of planar topological defects in unconventional superconductors. Specifically, we calculate microscopically the interaction energy of domain walls separating degenerate ground states in a chiral p-wave fermionic superfluid. The interaction is mediated by the quasiparticles experiencing Andreev scattering at the domain walls. As a by-product, we derive a useful general expression for the free energy of an arbitrary nonuniform texture of the order parameter in terms of the quasiparticle scattering matrix. The thesis is structured as follows. We begin with a historical review of the theories of superconductivity (Sec. 1.1), which led the way to the celebrated Bardeen-Cooper- Schrieffer (BCS) theory (Sec. 1.3). Then we proceed to the treatment of superconductors with so-called "unconventional pairing" in Sec. 1.4, and in Sec. 1.5 we introduce the specific case of chiral p-wave superconductivity. After introducing in Sec. 2 the domain wall (DW) model that will be considered throughout the work, we derive the Bogoliubov-de Gennes (BdG) equations in Sec. 3.1, which determine the quasiparticle excitation spectrum for a nonuniform superconductor. In this work, we use the semiclassical (Andreev) approximation, and solve the Andreev equations (which are a particular case of the BdG equations) in Sec. 4 to determine the quasiparticle spectrum for both the single- and two-DW textures. The Andreev equations are derived in Sec. 3.2, and the formal properties of the Andreev scattering coefficients are discussed in the following subsection. In Sec. 5, we use the transfer matrix method to relate the interaction energy of the DWs to the scattering matrix of the Bogoliubov quasiparticles. This facilitates the derivation of an analytical expression for the interaction energy between the two DWs in Sec. 5.3. Finally, to illustrate the general applicability our method, we apply it in Sec. 6 to the interaction between phase solitons in a two-band s-wave superconductor.