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)

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..

The effects of the vacuum electromagnetic fluctuations and the radiation reaction fields on the time development of a simple microscopic system are identified using a new mathematical method. This is done by studying a charged mechanical oscillator (frequency Ω 0)within the realm of stochastic electrodynamics, where the vacuum plays the role of an energy reservoir. According to our approach, which may be regarded as a simple mathematical exercise, we show how the oscillator Liouville equation is transformed into a Schrödinger-like stochastic (...) equation with a free parameter h′ with dimensions of action. The role of the physical Planck's constant h is introduced only through the zero-point vacuum electromagnetic fields. The perturbative and the exact solutions of the stochastic Schrödinger-like equation are presented for h′>0. The exact solutions for which h′<h are called sub-Heisenberg states. These nonperturbative solutions appear in the form of Gaussian, non-Heisenberg states for which the initial classical uncertainty relation takes the form 〈(δx 2)〉〈(δp) 2 〉=(h′/2) 2,which includes the limit of zero indeterminacy (h → 0). We show how the radiation reaction and the vacuum fields govern the evolution of these non-Heisenberg states in phase space, guaranteeing their decay to the stationary state with average energy hΩ 0 /2 and 〈(δx) 2 〉〈(δp) 2 〉=h 2 /4 at zero temperature. Environmental and thermal effects-are briefly discussed and the connection with similar works within the realm of quantum electrodynamics is also presented. We suggest some other applications of the classical non-Heisenberg states introduced in this paper and we also indicate experiments which might give concrete evidence of these states. (shrink)

The overflow of scientific literature stimulates poor reading habits which can aggravate science's reproducibility crisis. Thus, solving the reproducibility crisis demands not only methodological changes, but also changes in our relationship with the scientific literature, especially our reading habits. Importantly, this does not mean reading more, it means reading better.

In recent years there has been a wealth of studies investigating how memories are allocated in the hippocampus. Some of those studies showed that it is possible to manipulate the identity of neurons recruited to represent a given memory without affecting the memory's behavioral expression. Those findings raised questions about how the hippocampus represents memories, with some researchers arguing that hippocampal neurons do not represent fixed stimuli. Herein, an alternative hypothesis is argued. Neurons in high‐order brain regions can be tuned (...) to multiple dimensions, forming complex, abstract representations. It is argued that such complex receptive fields allow those neurons to show some flexibility in their responses while still representing relatively fixed sets of stimuli. Moreover, it is pointed out that changes induced by artificial manipulation of cell assemblies are not completely redundant—the observed behavioral redundancy does not imply cognitive redundancy, as different, but similar, memories may induce the same behavior. (shrink)

We give an example in which it is possible to understand quantum statistics using classical concepts. This is done by studying the interaction of chargedmatter oscillators with the thermal and zeropoint electromagnetic fields characteristic of quantum electrodynamics and classical stochastic electrodynamics. Planck's formula for the spectral distribution and the elements of energy hw are interpreted without resorting to discontinuities. We also show the aspects in which our model calculation complement other derivations of blackbody radiation spectrum without quantum assumptions.

Graphical AbstractThis paper discusses how our bad reading habits are starting to influence how we write. This short abstract and the picture next to it summarize the arguments in this paper. Just kidding, they do not. One really needs to read the paper for that.

The effects of the vacuum electromagnetic fluctuations and the radiation reaction fields on the time development of a simple microscopic system are identified using a new mathematical method. This is done by studying a charged mechanical oscillator (frequency Ω 0)within the realm of stochastic electrodynamics, where the vacuum plays the role of an energy reservoir. According to our approach, which may be regarded as a simple mathematical exercise, we show how the oscillator Liouville equation is transformed into a Schrödinger-like stochastic (...) equation with a free parameter h′ with dimensions of action. The role of the physical Planck's constant h is introduced only through the zero-point vacuum electromagnetic fields. The perturbative and the exact solutions of the stochastic Schrödinger-like equation are presented for h′>0. The exact solutions for which h′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)

Bibliographic negligence, i.e. omission of citation of the relevant work of other researchers, is possibly the most common type of research misconduct, leading to unfair loss of priority of authorship and undermining the reward system of science. We report a case of bibliographic negligence which we recently suffered from a leading biomedical journal. The case is discussed in the context of the editorial policy of the journal and of relevant ethical guidelines. Scientific journals should develop codes of conduct for citations. (...) In addition, the implications and consequences of bibliographic negligence deserve thorough investigation. (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)

We make a brief review of the Kramers escape rate theory for the probabilistic motion of a particle in a potential well U(x), and under the influence of classical fluctuation forces. The Kramers theory is extended in order to take into account the action of the thermal and zero-point random electromagnetic fields on a charged particle. The result is physically relevant because we get a non-null escape rate over the potential barrier at low temperatures (T → 0). It is found (...) that, even if the mean energy is much smaller than the barrier height, the classical particle can escape from the potential well due to the action of the zero-point fluctuating fields. These stochastic effects can be used to give a classical interpretation to some quantum tunneling phenomena. Relevant experimental data are used to illustrate the theoretical results. (shrink)

We consider the simple case of a nonrelativistic charged harmonic oscillator in one dimension, to investigate how to take into account the radiation reaction and vacuum fluctuation forces within the Schrödinger equation. The effects of both zero-point and thermal classical electromagnetic vacuum fields, characteristic of stochastic electrodynamics, are separately considered. Our study confirms that the zero-point electromagnetic fluctuations are dynamically related to the momentum operator p=−i ℏ ∂/∂ x used in the Schrödinger equation.

There is growing interest in tissue procurement for cancer research through autopsy. Establishing an autopsy/tissue donation programme for breast cancer research within an academic medical centre i...

Caracterización de un grupo de comités de ética en investigación en Colombia Caracterização de um grupo de comitês de ética em pesquisa na Colômbia In the last decades, controlled clinical trials sponsored by the pharmaceutical industry have increased considerably. This has led to the need for greater control and assistance by regulators and ethics committees to ensure appropriate compliance with established ethical standards and good clinical practices in general. In Colombia, the National Food and Drug Surveillance Institute, the regulator in (...) the country, controls and monitors the operation of clinical research with drugs. In 2008, this entity issued Resolution 2378, which provides and regulates research actors in Colombia, including ethics committees. After being in force for several years, it is necessary to know whether research ethics committees in Colombia operate in accordance with this regulation and to determine the status of implementation of the requirements therein. For this purpose, a survey was designed to be voluntarily answered and a response was obtained from 25 of the 69 certified committees in Colombia. Twenty-two of them could be analyzed because their information was complete. Compared with previous studies, favorable changes in development and organization were observed in accordance with the current proposed regulation. Para citar este artículo / To reference this article / Para citar este artigo Suárez-Obando F, Reynales H, Urina M, Camacho J, Viteri M. Caracterización de un grupo de comités de ética en investigación en Colombia. pers. bioét. 2018; 22: 303-318. DOI: 10.5294/pebi.2018.22.2.8. (shrink)

The book, volume 42 in the Boston Studies in the Philosophy of Science, consists principally of two interconnected essays in theoretical biology. The first, entitled "Biology of Cognition," was written in 1969 by Humberto R. Maturana, a Chilean neurophysiologist and anatomist whose earlier work included studies of vision in birds and the frog. The second essay, "Autopoiesis: the Organization of the Living," is an expansion of certain sections in the first and was written in 1972 by Maturana and Francisco (...) J. Varela, a philosophical biologist. Although Maturana alone is responsible for the introduction, the two essays are said to represent one point of view, expressed in the concept of "autopoiesis." The term, "a word without a history," was invented to convey "the central feature of the organization of the living, which is autonomy". Autopoiesis, it is claimed, enables us to say at once, through the logic of a self-referring homeostatic system, what is organic life and cognition. "Living systems are cognitive systems, and living as a process is a process of cognition". (shrink)

ABSTRACTThis article reviews Humberto Llavador, John Roemer, and Joaquim Silvistre’s 2015 book on the economics of climate change, Sustainability for a Warming Planet. While the book is written for economists, its arguments should be of interest to environmental philosophers and interdisciplinary scholars of climate change. After summarizing the book’s chapters, I offer modest criticisms and a brief commentary on the scope and limits of economic modeling of climate change decisions.

This study described the relationships between academic class and student moral sensitivity and reasoning and between curriculum design components for ethics education and student moral sensitivity and reasoning. The data were collected from freshman (n = 506) and senior students (n = 440) in eight baccalaureate nursing programs in South Korea by survey; the survey consisted of the Korean Moral Sensitivity Questionnaire and the Korean Defining Issues Test. The results showed that moral sensitivity scores in patient-oriented care and conflict were (...) higher in senior students than in freshman students. Furthermore, more hours of ethics content were associated with higher principled thinking scores of senior students. Nursing education in South Korea may have an impact on developing student moral sensitivity. Planned ethics content in nursing curricula is necessary to improve moral sensitivity and moral reasoning of students. (shrink)

This essay is part of a special issue celebrating 50 years of Political Theory. The ambition of the editors was to mark this half century not with a retrospective but with a confabulation of futures. Contributors were asked: What will political theory look and sound like in the next century and beyond? What claims might political theorists or their descendants be making in ten, twenty-five, fifty, a hundred years’ time? How might they vindicate those claims in their future contexts? How (...) will the consistent concerns of political theorists evolve into the questions critical for people decades or centuries from now? What new problems will engage the political theorists (or their rough equivalents) of the future? What forms might those take? What follows is one of the many confabulations published in response to these queries. (shrink)

"Knowing how we know" is the subject of this book. Its authors present a new view of cognition that has important social and ethical implications, for, they assert, the only world we humans can have is the one we create together through the actions of our coexistence. Written for a general audience as well as for students, scholars, and scientists and abundantly illustrated with examples from biology, linguistics, and new social and cultural phenomena, this revised edition includes a new afterword (...) by Dr. Varela, in which he discusses the effect the book has had in the years since its first publication. (shrink)

Zygon®, Volume 57, Issue 1, Page 46-59, March 2022.

En este artículo postulamos que el trabajo de Kuhn es una revolución filosófica para la filosofía de la ciencia. La búsqueda de revoluciones filosóficas es una extensión de las ideas de Kuhn acerca de las revoluciones científicas. Las revoluciones filosóficas se distinguen de las revoluciones científicas en algunos aspectos que discutimos en este trabajo. Defendemos que la revolución kuhniana consiste en la naturalización de la filosofía de la ciencia que se desprende de sus trabajos y discutimos la analogía biológica que (...) Kuhn empleó como un ejemplo ilustrativo. (shrink)

Philosophers such as Elizabeth Anscombe and Donald Davidson have explained that we cannot derive predictions from judgments such as "he boasted from vanity." Such judgments are also the source of countless painful mistakes. However, are they necessarily unreliable? Often enough, even if only gradually and partially, we get people right. Assuming that we do is already assuming that there must be a connection, if not causal then at least casual, between what a person is, what she does, and how she (...) acts; and that we may describe it correctly. If no ironclad generalizations can be made that connect the way a person is, her reasons, and her actions, how might we describe correctness in judgments such as this?Anscombe... (shrink)

En la formación inicial docente, el estudio de la epistemología constituye una pieza fundamental para que los futuros profesores puedan filosofar sobre la realidad de los diversos contextos educativos y se pregunten cómo mejorarla desde los principios que rigen la investigación científica. De este modo, gracias al sustento epistemológico, los estudiantes de pedagogía pueden formarse como docentes investigadores capaces de analizar los cambios sociales propuestos por las múltiples realidades y conocer cómo se construye el conocimiento científico de una especialidad dada. (...) La finalidad de este trabajo, es presentar una reflexión filosófica-epistemológica sobre la imperiosa necesidad de desarrollar el conocimiento epistemológico en la formación inicial del profesorado de matemática e historia, considerando los fundamentos disciplinares, pedagógicos y cognitivos de dichas áreas. (shrink)

Here they are revised notions of the Western tradition that conform the discourse of poetic reason, and the way that Maria Zambrano assumed them. Her thought examines the possibilities of the words, either poetic or philosophical, to allow persons to get conscience. She attempts to unify both types of words using a notion of love as essential intent for dealing with the otherness, allowing, also, the human being conscious reflection on the affectivity. To achieve this, she revises culture to find (...) ideas and examples to support the poetic reason as loving and hopeful reflection and as a possibility of the humanity to know about its own feelings. (shrink)

We propose that to understand the biological and neurophysiological processes that give rise to human mental phenomena it is necessary to consider them as behavioral relational phenomena. In particular, we propose that: a) these phenomena take place in the relational manner of living that human language constitutes, and b) that they arise as recursive operations in such behavioral domain. Accordingly, we maintain that these phenomena do not take place in the brain, nor are they the result of a unique operation (...) of a human brain, but arise with the participation of the brain as it generates the behavioral relational dynamics that constitutes language. (shrink)

En el presente trabajo se propone un estudio comparativo de las producciones de algunos referentes de la Investigación Participativa. Se revisan algunos de los textos de Orlando Fals Borda, Paulo Freire, João Bosco Guedes Pinto, Michel Thiollent, María Teresa Sirvent y Joel Martí. Este trabajo se inscribe en el proceso reciente de transformación universitaria en Uruguay, en particular, en una de sus iniciativas: la de la integración curricular de la extensión a través de lo que se ha denominado “prácticas universitarias (...) integrales”. En este marco, la reflexión teórico-metodológica sobre la extensión crítica y las prácticas de investigación-acción conectadas con ella resultan fundamentales para dotar las iniciativas en curso de mayor pertinencia académica y potencial transformador. (shrink)