La respuesta a la pregunta del título se ofrece en tres niveles. A veces las diferencias se deben a las limitaciones del equipo empleado, deficiencias en el muestreo o preferencias en la interpretación de los datos. Otras veces se deben a que los investigadores operan en base a paradigmas diferentes..

We present a description of the Stern–Gerlach type experiments using only the concepts of classical electrodynamics and the Newton’s equations of motion. The quantization of the projections of the spin (or the projections of the magnetic dipole) is not introduced in our calculations. The main characteristic of our approach is a quantitative analysis of the motion of the magnetic atoms at the entrance of the magnetic field region. This study reveals a mechanism which modifies continuously the orientation of the magnetic (...) dipole of the atom in a very short time interval, at the entrance of the magnetic field region. The mechanism is based on the conservation of the total energy associated with a magnetic dipole which moves in a non uniform magnetic field generated by an electromagnet. A detailed quantitative comparison with the (1922) Stern–Gerlach experiment and the didactical (1967) experiment by J.R. Zacharias is presented. We conclude, contrary to the original Stern–Gerlach statement, that the classical explanations are not ruled out by the experimental data. (shrink)

In this introduction to the first installment of the Common Knowledge symposium on xenophilia, the editor explains the rationale of the new project, citing increases in aggressive xenophobia internationally. He comments on the intergroup-relations theorist Todd Pittinsky's argument that, since tolerance is not logically the antithesis of negative feelings toward out-groups, even long-established traditions of toleration are inadequate to prevent intergroup aggression. Pittinsky proposes that tolerance be replaced, as a principle of peacekeeping, by the encouragement of positive feelings toward out-groups, (...) and the author of this essay responds by showing how the Freudian theory of ambivalence and the history of literature on which Freud drew in constructing it support Pittinsky's viewpoint. Enemies regularly fall in love, above all in Shakespearean drama, which Freud explains by arguing that all human relations are love-hate relations. Thus, this essay suggests, it takes as much psychic energy to repress the love in what appear to be relationships of hatred as to repress the hatred in what appear to be relationships of love. There is a metaphysical component as well to this argument: the xenophobe and xenophile equally presuppose that the identity principle is applicable to society as well as to mathematics; both assume that each discrete social group is self-identical and differs from all other groups more or less radically. The main difference between –phile and –phobe is the latter's relative incapacity to live with ambivalence. Given these arguments, one must expect to find negative as well as positive motives in the etiology and conduct of xenophilia—and the first installment of the Common Knowledge symposium is said to focus on cases of xenophilia in which varieties of enmity accompany that singular and underrated variety of love. (shrink)

The development and use of advanced and innovative neuroscience, neurotechnology and some forms of artificial intelligence have exposed potential threats to the human condition, including human rights. As a result, reconceptualizing or creating human rights (i.e. neurorights) has been proposed to address specific brain and mind issues like free will, personal identity and cognitive liberty. However, perceptions, interpretations and meanings of these issues—and of neurorights—may vary between countries, contexts and cultures, all relevant for an international-consensus definition and implementation of neurorights. (...) Thus, we encourage reflecting on the proactive inclusion of transnational, cross-cultural and contextual considerations and concerns to contribute to the global discourse. This inclusion does not mean endorsing ethical relativism but rather a call to foster a universal understanding of key concepts and concerns. Including contextual and cultural perspectives may truly anticipate global concerns which could be addressed while developing and implementing neurorights. Consequently, any ethical and/or legal regulatory framework(s) for the translational and transnational use of advanced neuroscience, neurotechnology and some forms of artificial intelligence intended to protect and safeguard human dignity should be contextually and culturally mindful, responsible, respectful and inclusive of not only human rights and fundamental freedoms but also of neurocognitive cultural diversity. (shrink)