This bibliographical review of the modelling of the mitotic apparatus covers a period of one hundred and twenty years, from the discovery of the bipolar mitotic spindle up to the present day. Without attempting to be fully comprehensive, it will describe the evolution of the main ideas that have left their mark on a century of experimental and theoretical research. Fol and Bütschli's first writings date back to 1873, at a time when Schleiden and Schwann's cell theory was rapidly gaining (...) ground throughout Germany. Both mitosis and chromosomes were to be discovered within the space of thirty years, along with the two key events in the animal and plant reproductive cycle, namely fecondation and meiosis. The mitotic pole, a term still in use to this day, was employed to describe a morphological fact which was noted as early as 1876, namely that the lines and the dots of the karyokinetic figure, with its spindle and asters, looks remarkably like the lines of force around a bar magnet. This was to lead to models designed to explain the movements of chromosomes which take place when the cell nucleus appears to cease to exist as an organelle during mitosis. The nature of those mechanisms and the origin of the forces behind the chromosomes' ordered movements were central to the debate. Auguste Prenant, in a remarkable bibliographical synthesis published in 1910, summed up the opposing viewpoints of the vitalists, on the one hand, who favoured the theory of contractility or extensility in spindle fibres, and of those who believed in models based on physical phenomena, on the other. The latter subdivided into two groups: some, like Bütschli, Rhumbler or Leduc, referred to diffusion, osmosis and superficial tension, whilst the others, led by Gallardo and Hartog, focussed on the laws of electromagnetism. Lillie, Kuwada and Darlington followed up this line of research. The mid-20th century was a major turning point. Most of the modelling mentioned above was criticized and fell into disuse after disappearing from research publications and textbooks.This marked the onset of a new era, as electron microscopes made possible the materialization and detailed study of the macromolecular elements of the fibres, filaments and microtubules of the cytoskeleton. The successive phases of (a) de Harven and Bernhard's 1956 discovery of the centriole's ultrastructure, (b) its identification with the basal body of the cilia and flagella, confirming the theory set out by Henneguy and von Lenhossek (1898–99), (c) the universal presence of microtubules in animal, vegetal and eukaryotic protist cells, (d) the polymerization-depolymerization induced reversible transformations of the tubulin pool in mitosing cells (Inoue, 1960), (e) ultrastructural comparative studies of the mitotic apparatus of eukaryotes illustrating the Pickett-Heaps integrating concept of the MTOC (microtubule-organizing centre), (f) the possibility ofin vitro experiments on mtocs or on microtubules, brings us upon the present day, which has seen the focus placed on the concept of motor-proteins (kinesin, dynein) and on cell cycle models. The latter are based on a close coincidence between the observable modifications of the mitotic apparatus and the periodic variations in intracellular concentrations of calcium or of certain enzymes (cyclins, Cdc2) during the main transitions of the cell cycle. (shrink)

Episodic memory has been analyzed in a number of different ways in both philosophy and psychology, and most controversy has centered on its self-referential, autonoetic character. Here, we offer a comprehensive characterization of episodic memory in representational terms and propose a novel functional account on this basis. We argue that episodic memory should be understood as a distinctive epistemic attitude taken toward an event simulation. In this view, episodic memory has a metarepresentational format and should not be equated with beliefs (...) about the past. Instead, empirical findings suggest that the contents of human episodic memory are often constructed in the service of the explicit justification of such beliefs. Existing accounts of episodic memory function that have focused on explaining its constructive character through its role in future-oriented mental time travel do justice neither to its capacity to ground veridical beliefs about the past nor to its representational format. We provide an account of the metarepresentational structure of episodic memory in terms of its role in communicative interaction. The generative nature of recollection allows us to represent and communicate the reasons why we hold certain beliefs about the past. In this process, autonoesis corresponds to the capacity to determine when and how to assert epistemic authority in making claims about the past. A domain where such claims are indispensable are human social engagements. Such engagements commonly require the justification of entitlements and obligations, which is often possible only by explicit reference to specific past events. (shrink)

We develop a partial solution to the meta-problem of consciousness that builds on our previous psychological account of an apparent explanatory gap. Drawing from empirical work on explanatory cognition and conceptual development, we sketch a profile of cognitive systems for which primitive concepts facilitate explanatory gaps. This account predicts that there will be multiple explanatory gaps. We suggest that this is borne out by the existence of primitivist theories in multiple philosophical domains.

Char et al. describe an interesting and useful approach in their paper, “Identifying ethical considerations for machine learning healthcare applications.” Their proposed framework, which see...

Open peer commentary on the article “Sensorimotor Direct Realism: How We Enact Our World” by Michael Beaton. Upshot: This commentary is broadly sympathetic to the claims made in the target article. I start by questioning whether we can have direct access to an external reality in such a way that our experience is not intrinsically private. I then suggest that the argument for direct realism presented here is inconclusive with regard to whether external objects play a causal or a constitutive (...) role. (shrink)

[v. 1] Thales to Democritus.--[v. 2] The Sophists. Socrates. Plato.--[v. 3] Aristotle.

In this article a brief overview is given of the field of medical ethics in Sweden in recent years. The presentation concentrates on the occurrence of official ethical norms for physicians, current ethical committees, the educational situation, legislation in force, and some essential features of the ethical debate on a few central issues.

An attempt is made here to examine the analysis three political thinkers - Thomas Paine, William Godwin, and Jeremy Bentham have offered of the idea of equality. The inquiry underrtaken is philosophical and not historical in character, since no attempt is made either at tracing the influence ht the biographical-cum-intellectual level of one of them upon the other or at treating their ideas on equality as born out of their preoccupation with the same problem to which they give various answers (...) and which can therefore be considered within a single overall framework. Instead, each thinker is considered independently. And a study is undertaken of the way he understands equality, the way he justifies it, the sort of equality he considers most important and his reasons for this, the area of life he takes the idea of equality to illuminate, the manner in which he relates it to other ideas, etc.. In each case, a fairly coherent philosophy of equality is sought to be constructed out of their respective writings. These three thinkers are selected for two reasons. The idea of equality looms quite large in their thought; as such, it was felt that looking at their writings from the standpoint of equality may illuminate their certain features that may otherwise remain obscure or relatively underemphasized. Further, as they consider equality from different philosophical positions it was believed that a critical examination of their writings could, perhaps, point to the general merits and limitations of their respective positions in terms of equality. in chapter I, it is argued that there are distinct views of God discernible in Paine's writings, and that corresponding to them are three distinct views of equality, though only two of them are discussed by Paine at any length. in chapter II, it is argued that, though Godwin begins as a thoroughgoing rationalist, three are shifts in his general philosophical position, and that, with each shift, his ideas on truth, rationality and equality undergo important changes. Finally, in chapter III, it is argued that there are two distinct theories of equality in Bentham and that tension between them remains unresolved. (shrink)

What, ultimately, is there good reason to do? This book proposes a unified theory of agent-dependent reasons and agent-independent reasons. It holds that principles which assign reasons to agents are valid if and only if they make maximally good sense in the light of relevant data and background theories. The theory avoids problems encountered by views associated with Nagel, Parfit, Brandt, Hubin, Gert, Baier, and Tiberius, amongst others. By what criteria should a normative theory of ultimate reasons be judged? Plausible (...) meta-level criteria emerge from a process of identifying the criteria that have been used, sometimes unwittingly, by various theorists; categorizing and evaluating the criteria in the light of each other; and proposing revisions on that basis. This method escapes the drawbacks of rival approaches, such as those associated with Parfit, Gert, and Darwall. The resulting criteria cast a favorable light on the proposed normative theory of ultimate reasons. (shrink)

El jesuita mexicano del siglo XVIII Clavigero fue considerado como el pensador más distinguido de su tiempo. Aquí se investiga su contribución a la introducción en México de la física moderna, considerada en su época como filosofía moderna.