This paper gives two complete and elementary proofs that if the speed of light over closed paths has a universal value c, then it is possible to synchronize clocks in such a way that the one-way speed of light is c. The first proof is an elementary version of a recent proof. The second provides high precision experimental evidence that it is possible to synchronize clocks in such a way that the one-way speed of light has a universal value. We (...) also discuss an old incomplete proof by Weyl which is important from an historical perspective. (shrink)

How do we live, then, so that all of nature bows down and we are in despair? “We wanted to change the world and the world changed us", says Nino Manfredi in Ettore Scola's film, C'eravamo tanto amati, something so expressive of this vital mode that dominates us. But to try not to be transformed by what we live seems impossible, even unfortunate, because a man always lives in his present, and in doing so lives with his fellow men. (...) Only in this way is it possible to live in a political society, to create a public sphere. Politics is born of sharing together, of words and deeds, as Hannah Arendt reminds us (3). (shrink)

¿Cómo vivimos, pues, para que toda la naturaleza se doblegue y estemos en la desazón? "Queríamos cambiar el mundo y el mundo nos cambió a nosotros”, dice Nino Manfredi en la película de Ettore Scola, C'eravamo tanto amati, algo tan expresivo de este modo vital que nos domina. Pero aspirar a que no nos transforme lo que vivimos parece imposible, incluso desafortunado, ya que un hombre vive siempre en su presente, y al hacerlo habita con sus semejantes. Sólo así (...) es posible vivir en una sociedad política, hacer una esfera pública. La política nace de compartir juntos, palabras y actos, nos recuerda Hannah Arendt (3). (shrink)