We explore the intimate connection between spacetime geometry and electrodynamics. This link is already implicit in the constitutive relations between the field strengths and excitations, which are an essential part of the axiomatic structure of electromagnetism, clearly formulated via integration theory and differential forms. We review the foundations of classical electromagnetism based on charge and magnetic flux conservation, the Lorentz force and the constitutive relations. These relations introduce the conformal part of the metric and allow the study of electrodynamics for (...) specific spacetime geometries. At the foundational level, we discuss the possibility of generalizing the vacuum constitutive relations, by relaxing the fixed conditions of homogeneity and isotropy, and by assuming that the symmetry properties of the electro-vacuum follow the spacetime isometries. The implications of this extension are briefly discussed in the context of the intimate connection between electromagnetism and the geometry of spacetime. (shrink)
When I moved into the Tenderloin district of San Francisco, I immediately noticed the epidemic of homelessness that seemed to blanket the entire neighborhood. Even more prevalent was the problem of drug abuse and alcoholism. It would truly be safe to say that 70-80% of the neighborhood's occupants fall into this category. In my experience, San Francisco has the largest number of homeless people as compared to other cities I have visited. I do realize there are locales such (...) as Detroit, Chicago, and New York that have equal if not larger problems with homelessness, but since San Francisco is where I call home, it will be the focus of this project. People in the Tenderloin were pushing everything from street drugs like heroin and cocaine, to prescription pills like Oxycontin and Vicodin. There was almost no reaction to these activities by the local police, except perhaps to unjustly harass individuals that didn’t necessarily deserve it. It was almost as if the city created a way to deal with the problem by sectioning off the Tenderloin for the outcasts of society to "thrive" in. As long as they stayed out of the wealthy areas, there would be no need for the local government to intervene or develop a long term solution. These are the premises that inspired me. So in the spring of 2006, I walked the streets of the Tenderloin day and night so as to capture the essence of the area in the most realistic way. All images were shot with a 35 mm film camera. My intention in creating this book is one of enlightenment so that people of all backgrounds can see the completely ignored deterioration of nearly a dozen city blocks… Streets entirely cluttered with despair placed conveniently within a stone's throw of the streets where wealthy tourists shop for thousand dollar handbags and five-dollar coffees. (shrink)
When I moved into the Tenderloin district of San Francisco, almost immediately, I noticed the epidemic of homelessness that seemed to blanket the entire neighborhood. Even more prevalent was the problem of drug abuse and alcoholism. It would truly be safe to say that 70-80% of the neighborhoods occupants fall into this category. In my experience, San Francisco has the largest number of homeless people as compared to other cities I have visited. I do realize there are locales (...) such as Detroit, Chicago, and New York that have equal if not larger problems with homelessness, but since San Francisco is where I call home, it will be the focus of this project. People in the Tenderloin were pushing everything from street drugs like heroin and cocaine, to prescription pills like oxy cotin and vicodin. There was almost no reaction to these activities by the local police, except perhaps to unjustly harass individuals that didn’t necessarily deserve it. It was almost as if the city created a way to deal with the problem by sectioning off the Tenderloin district for the outcasts of society to thrive in. As long as they stayed out of the wealthy areas, there would be no need for the local government to intervene or develop a long term solution. These are the premises that inspired me. So in the Spring of 2006, I walked the streets of the Tenderloin day and night so as to capture the essence of the area in the most realistic way. All images were shot with a 35 mm film camera. My intention in creating this book is one of enlightenment, so that people of all backgrounds can see the completely ignored deterioration of nearly a dozen city blocks… Streets entirely cluttered with despair placed conveniently within a stones throw of the streets where wealthy tourists shop for thousand dollar handbags and five dollar coffees. (shrink)
Ever since it was annexed from northern Mexico in 1848, San Francisco has catered to tourists attracted to its good year-round weather, natural splendor, as well as its licentious entertainment industry and, since the 1950s, the buoyancy of its lesbian and gay community. The author looks at the growth and vibrancy of alternative lifestyles in San Francisco, arguing that the visibility of the queer community there is not the result of general tolerance in the Western outpost but, paradoxically, (...) the outcome of a struggle between the lesbian, gay, and transgendered residents of the city and the repressive local, state, and federal agencies whose harassment of the alternative communities, culminating in the 1930s and 1940s in frequent bar-raids, arrests, and the “war on vice,” brought about the queer community’s politicization and grovving militancy. (shrink)
The Schwarzschild solution has played a fundamental conceptual role in general relativity, and beyond, for instance, regarding event horizons, spacetime singularities and aspects of quantum field theory in curved spacetimes. However, one still encounters the existence of misconceptions and a certain ambiguity inherent in the Schwarzschild solution in the literature. By taking into account the point of view of an observer in the interior of the event horizon, one verifies that new conceptual difficulties arise. In this work, besides providing a (...) very brief pedagogical review, we further analyze the interior Schwarzschild black hole solution. Firstly, by deducing the interior metric by considering time-dependent metric coefficients, the interior region is analyzed without the prejudices inherited from the exterior geometry. We also pay close attention to several respective cosmological interpretations, and briefly address some of the difficulties associated to spacetime singularities. Secondly, we deduce the conserved quantities of null and timelike geodesics, and discuss several particular cases in some detail. Thirdly, we examine the Eddington–Finkelstein and Kruskal coordinates directly from the interior solution. In concluding, it is important to emphasize that the interior structure of realistic black holes has not been satisfactorily determined, and is still open to considerable debate. (shrink)
If Justice Louis Brandeis were alive to witness San Francisco’s recent experiment with universal health care legislation, he might amend his famous characterization of the states as “laboratories of democracy” to include municipalities as well. In San Francisco, where ten percent of residents have no health insurance and where fifteen percent of businesses provide no health coverage for their employees, the Board of Supervisors recently passed the San Francisco Health Care Security Ordinance, which funds a network of (...) primary care services for uninsured residents. While the Ordinance has, in the main, met with general approval, its provision mandating contributions from local businesses that do not meet minimum health spending requirements is the subject of ongoing litigation. The Ninth Circuit Court of Appeals recently ruled in the city’s favor, thereby allowing the spending provision to go forward pending a full appeal on the merits of the case. (shrink)
_Dialectic and Dialogue_ seeks to define the method and the aims of Plato's dialectic in both the "inconclusive" dialogues and the dialogues that describe and practice a method of hypothesis. Departing from most treatments of Plato, Gonzalez argues that the philosophical knowledge at which dialectic aims is nonpropositional, practical, and reflexive. The result is a reassessment of how Plato understood the nature of philosophy.
In this paper I draw on Einstein's distinction between “principle” and “constructive” theories to isolate two levels of physical theory that can be found in both classical and (special) relativistic physics. I then argue that when we focus on theoretical explanations in physics, i.e. explanations of physical laws, the two leading views on explanation, Salmon's “bottom-up” view and Kitcher's “top-down” view, accurately describe theoretical explanations for a given level of theory. I arrive at this conclusion through an analysis of explanations (...) of mass—energy equivalence in special relativity. (shrink)
This paper defends a ‘perspectivist’ reading of Plato’s dialogues. According to this reading, each dialogue presents a particular and limited perspective on the truth, conditioned by the specific context, aim and characters, where this perspective, not claiming to represent the whole truth on a topic, is not incompatible with the possibly very different perspectives found in other dialogues nor, on the other hand, can be subordinated or assimilated to one of these other perspectives. This model is contrasted to the other (...) models that have been proposed, i.e., Unitarianism, Developmentalism, and ‘Prolepticism’, and is shown to address and overcome the limitations of each. One major advantage of ‘perspectivism’ against the other interpretative models is that, unlike them, it can do full justice to the literary and dramatic character of the dialogues without falling into the opposite extreme of turning them into literary games with no positive philosophical content. To say that Plato’s dialogues are ‘perspectivist’ is not to say that they contain no ‘doctrines’ on the soul, for example, but, on the contrary, to stress the plurality of doctrines, with the observation that each is true within the limits of the argumentative function it is introduced to serve and of the specific dialogical context. (shrink)
Cognition is context-sensitive, as the same sensory information is processed differently depending on its context (e.g., on its probabilistic association with goal-directed actions and their outcomes). Despite this, the concept of context in studies of higher-order cognitive processes, like cognitive control, is often simplified to nominal stimulus categories (like a target vs. distractor). Here we propose that quantifying contextual information to model cognitive demands is (1) fruitful as it can provide novel insight into the nature of cognitive control, (2) accessible (...) as simple probability models offer a tool for quantifying context and (3) analytically useful as a fine-grained quantification of context can be entered into more complex models as regressors that allow a direct way of appropriately exploring many of the defining tenants of cognitive control (e.g., rapidly changing trial-by-trial neural dynamics). Here, we briefly describe the logic of using context-sensitive measures of cognitive control and highlight recent studies from this approach using simple information theory metrics. (shrink)
Interpretations of Einstein’s equation differ primarily concerning whether E = mc2 entails that mass and energy are the same property of physical systems, and hence whether there is any sense in which mass is ever ‘converted’ into energy. In this paper, I examine six interpretations of Einstein’s equation and argue that all but one fail to satisfy a minimal set of conditions that all interpretations of physical theories ought to satisfy. I argue that we should prefer the interpretation of Einstein’s (...) equation that holds that mass and energy are distinct properties of physical systems. This interpretation also carries along the view that while most cases of ‘conversion’ are not genuine examples of mass being ‘converted’ into energy, it is possible that the there are such ‘conversions’ in the sense that a certain amount of energy ‘appears’ and an equivalent of mass ‘disappears’. Finally, I suggest that the interpretation I defend is the only one that does not blur the distinction between what Einstein called ‘principle’ and ‘constructive’ theories. This is philosophically significant because it emphasizes that explanations of Einstein’s equation and the ‘conversion’ of mass and energy must be top‐down explanations. (shrink)
Several authors, such as William J. Morgan, John S. Russell and R. Scott Kretchmar, have claimed that the limits between the diverse normative theories of sport need to be revisited. Most of these works are philosophically grounded in Anglo-American philosophical approaches. For instance, William J. Morgan’s proposal is mainly based on Richard Rorty’s philosophy. But he also discusses with some European philosophers like Jürgen Habermas. However, Habermas’ central ideas are rejected by Morgan. The purpose of this paper is to analyse (...) Morgan’s rejection of Habermas’ thought and show that a more appropriate normative of sport that explains better our current sporting world can be achieved by drawing on the German philosopher’s ideas. The plan of this paper is the following. It shall analyse the limits of the distinction between broad internalism and externalism by taking Morgan’s work as its starting point. To do so, firstly, the conventionalist way in which Morgan criticises the limits of interpretivism sha.. (shrink)
Einstein’s 1935 derivation of mass—energy equivalence is philosophically important because it contains both a criticism of purported demonstrations that proceed by analogy and strong motivations for the definitions of the ‘new’ dynamical quantities. In this paper, I argue that Einstein’s criticism and insights are still relevant today by showing how his derivation goes beyond Friedman’s demonstration of this result in his Foundations of Spacetime ¹heories. Along the way, I isolate three distinct physical claims associated with Einstein’s famous equation that are (...) sometimes not clearly distinguished in philosophical discussions of spacetime theory. (shrink)
In the recently published 1924 course, Grundbegriffe der aristotelischen Philosophie, Martin Heidegger offers a detailed interpretation of Aristotle’s definition of kinesis in the Physics. This interpretation identifies entelecheia with what is finished and present-at-an-end and energeia with being-at-work toward this end. In arguing against this interpretation, the present paper attempts to show that Aristotle interpreted being from the perspective of praxis rather than poiesis and therefore did not identify it with static presence. The paper also challenges later variations of Heidegger’s (...) interpretation, in particular his account of dunamis in the 1931 course on Metaphysics Theta, which insists that its mode of being is presence-at-hand. By arguing that this reading too is untenable, the paper concludes that Aristotle’s metaphysics is not a metaphysics of presence and that his texts instead point toward a possibility of metaphysics ignored by the attempts of Heidegger and others to overcome it. (shrink)
In this paper I describe the context and goals of Francisco Vallés' In IV librum Meteorologicorum commentaria. Vallés' work stands as a landmark because it interprets a work of Aristotle's natural philosophy specifically for medical doctors and medical theory. Vallés' commentary is representative of new understandings of Galenic-Hippocratic medi-cine that emerged as a result of expanding textual knowledge. These approaches are evident in a number of sixteenth-century commentaries on Meteorologica IV; in particular the works of Pietro Pomponazzi, Lodovico Boccadiferro, (...) Jacob Schegk, and Francesco Vimercati. Vallés' conviction that Meteorologica IV is relevant to medical knowledge depends on his understanding of Aristotle's theory of homeomerous substances and their relation to composite substances. The application of Meteorologica IV to medical topics became commonplace in the following years, and this Aristotelian book became widely known as a bridge between natural philosophy and medicine. (shrink)
ABSTRACTIn this article, I will identify two key normative principles at the core of Robert L. Simon’s mutualist theory of sport, namely, the respect-for-the-opponent principle and the idea that sport is a practice aimed at pursuing excellence. The former is a Kantian principle grounded in human beings’ rationality, and the latter is an Aristotelian principle related to the development of excellences as a means to human flourishing. After having presented and analyzed both principles, I will critically evaluate Simon’s attempt to (...) combine them within his mutualist approach. To conclude, I will highlight the challenges that mutualism should face to complete such a combination more successfully.Abbreviation: Categorical imperative. (shrink)
It is necessarily true that water is H2O, but it is a contingent fact that there is any water at all. Water therefore seems ill suited to ground the necessary truth that water is H2O. One view traditionally attributed to Scotus and Henry of Ghent was that while water is contingent, the essence of water is necessary; hence, the essence of water can ground the so-called eternal truth that water is H2O. Francisco Suárez rejects this view on the grounds (...) that it contradicts the Christian doctrine of creation, according to which everything other than God was contingently created in time. Suárez’s own view of the eternal truths has proven elusive to commentators, but I argue that Suárez ultimately endorses a version of the view he rejects: essences ground the eternal truths. But this raises several puzzles: how is Suárez’s view distinct from the views traditionally ascribed to Scotus and Henry? How does Suárez’s view escape the argument from creation, which Suárez raises against his opponents? I argue that Suárez distinguishes between his view and his opponents’ view by saying that essences have “extrinsic being,” whereas his opponents claim that essences have “intrinsic being.” The distinction between intrinsic and extrinsic being has not received much attention, but I argue that it marks an important fault line in scholastic thinking about the ontological status of non-existents. I argue that the notion of extrinsic being can be explicated in terms of ontological pluralism and grounding. The notion of extrinsic being helps differentiate Suárez’s view from his Scotistic and Henrician opponents, and it allows Suárez to respond to the creation argument he raises against his opponents. On my reading, Suárez’s solution to the problem of eternal truths turns out to be both highly original and philosophically satisfying. (shrink)
According to the received view, Russell rediscovered about 1900 the logical definition of cardinal number given by Frege in 1884. In the same way, we are told, he stated and developed independently the idea of logicism, using the principle of abstraction as the philosophical ground. Furthermore, the role commonly ascribed in this to Peano was only to invent an appropriate notation to be used as mere instrument. In this paper I hold that the study of Russell's unpublished manuscripts and Peano's (...) (and disciples) writings (as part of a larger investigation only pointed out here) shows, on the contrary, that Russell obtained the method to transform definitions by abstraction into nominal definitions and the general logicist idea from Peano (and his school). The only original insight from Russell, the principle of abstraction, partially derived from Moore's early philosophy, was finally abandoned because it was not of practical use. (shrink)
This paper offers a particular intuitionistic negation completion of Urquhart's system C resulting in a super-intuitionistic contractionless propositional logic equivalent to Dummett's LC without contraction.
Bell’s spaceship ‘paradox’  in special relativity is a particularly good one to examine with students, because although it deals with accelerated motions, it can be dissolved with elementary space–time diagrams. Furthermore, it forces us to be very clear about the relativity of simultaneity, proper length, and the ‘reality’ of the Lorentz contraction.
We explore the distinctive characteristics of Mexico's society, politics and history that impacted the establishment of genetics in Mexico, as a new disciplinary field that began in the early 20th century and was consolidated and institutionalized in the second half. We identify about three stages in the institutionalization of genetics in Mexico. The first stage can be characterized by Edmundo Taboada, who was the leader of a research program initiated during the Cárdenas government (1934-1940), which was primarily directed towards improving (...) the condition of small Mexican farmers. Taboada is the first Mexican post-graduate investigator in phytotechnology and phytopathology, trained at Cornell University and the University of Minnesota, in 1932 and 1933, respectively. He was the first investigator to teach plant genetics at the National School of Agriculture and wrote the first textbook of general genetics, Genetics Notes, in 1938. Taboada's most important single genetics contribution was the production of "stabilized" corn varieties. The extensive exile of Spanish intellectuals to Mexico, after the end of Spain's Civil War (1936-1939), had a major influence in Mexican science and characterizes the second stage. The three main personalities contributing to Mexican genetics are Federico Bonet de Marco and Bibiano Fernández Osorio Tafall, at the National School of Biological Sciences, and José Luis de la Loma y Oteyza, at the Chapingo Agriculture School. The main contribution of the Spanish exiles to the introduction of genetics in Mexico concerned teaching. They introduced in several universities genetics as a distinctive discipline within the biology curriculum and wrote genetics text books and manuals. The third stage is identified with Alfonso León de Garay, who founded the Genetics and Radiobiology Program in 1960 within the National Commission of Nuclear Energy, which had been founded in 1956. The Genetics and Radiobiology Program rapidly became a disciplinary program, for it embraced research, teaching, and training of academics and technicians. The Mexican Genetics Society, created by de Garay in 1966, and the development of strains and cultures for genetics research were important activities. One of de Garay's key requirements was the compulsory training of the Program's scientists for at least one or two years in the best universities of the United States and Europe. De Garay's role in the development of Mexican genetics was fundamental. His broad vision encompassed the practice of genetics in all its manifestations. (shrink)
This paper is a sequel to ‘Belnap-Dunn semantics for natural implicative expansions of Kleene's strong three-valued matrix with two designated values’, where a ‘bivalent’ Belnap-Dunn semantics is provided for all the expansions referred to in its title. The aim of the present paper is to carry out a parallel investigation for all natural implicative expansions of Kleene's strong 3-valued matrix now with only one designated value.
El artículo pretende contribuir a la discusión actual en torno al «caso Heidegger». En concreto, se intentarán mostrar tres gestos políticos correspondientes a tres momentos distintos de la evolución de su pensamiento: el neokantismo, la fenomenología hermenéutica y la ontohistoria. Se planteará hasta qué punto son distintos estos gestos, qué tienen en común y, sobre todo, qué lugar político se le concede a la filosofía en ellos. This paper aims to contribute to the current discussion around the «case Heidegger». It (...) shows three political gestures corresponding to three different moments in the evolution of his thought: neo-kantianism, hermeneutic phenomenology and history of Being. We will consider if this gestures are actually different, what do they have in common, and, especially, which political place is granted to philosophy in them. (shrink)
Beings of reason present metaphysicians with an interesting dilemma—they can be thought about even though there are no such things; yet to be thought about it would seem that they must have some kind of being. In this essay it is argued that Suárez presented a sophisticated alternative to Meinongism that is absent from contemporary discussions of beings of reason. Suárez’s doctrine is analysed in terms of ‘tethered counterfactuals’—they are tethered because they and their being are tied to acts of (...) intellection and counterfactual because the intellect treats them as if they existed even though they do not. (shrink)
El artículo expone el papel del otro y de lo otro en la hermenéutica de Gadamer a la luz de la idea de diálogo. Para comprender se requiere reconocer lo otro en su carácter de tú, asumir que no se tiene distancia frente a él y estar abierto a acoger lo dicho por él como una posible verdad. La compresión posee una estructura dialéctica que implica la cancelación de las propias expectativas y el acceso a un saber más abarcante. Aunque (...) la comprensión es histórica, en ella se muestra cada vez un aspecto de la cosa misma, que resulta de la interacción del yo y el tú en el curso de la conversación hermenéutica y que constituye una verdad común con caracteres análogos a los del saber de tipo práctico. [The paper exposes the role of the other in Gadamer’s hermeneutics in the light of the idea of dialogue. Understanding requires the recognition of the other as a thou, the acceptance of the lack of distance from him and the openness to embrace what is said by him as a possible truth. Understanding has a dialectical structure which implies the cancellation of one’s own expectations and the access to a more comprehensive knowledge. Even though every understanding is historical, it discloses an aspect of the thing itself, which results from the interaction of the I and the thou during the process of hermeneutical conversation and constitutes a common truth with analogous characteristics to practical reason.] . (shrink)