Le modèle unificationniste de l’explication métaphysique, basé sur les travaux de Kitcher sur l’explication scientifique, offre une alternative intéressante aux modèles présumant la conception supportive de l’explication métaphysique [backing model]. Par contre, le caractère adéquat de ce modèle, i.e. sa capacité à classifier comme métaphysiquement explicative/non-explicative des propositions qui préthéoriquement sont classés comme tel, n’a pas encore été exploré. Pour ce faire, des interprétations pour les relations de détermination et d’appartenance à un ensemble sont fournies. Celles-ci étant potentiellement sujette au (...) problème d’artificialité, i.e. présence d’un biais structurel favorisant l’attribution du caractère explicatif, une réponse est offerte. En effet, le modèle unificationniste permet d’identifier les patrons argumentatifs pouvant être légitimement mis en compétition en comparant la distance entre les ensembles de faits qui doivent être considérés comme vrais dans la formulation d’un patron argumentatif. Cette propriété a des conséquences intéressantes dans l’identification du niveau adéquat de débat entre des propositions compétitrices. (shrink)

Le problème de l’induction (humien) a récemment été abordé par Steel dans son article de 2010. Celui-ci soutient que les théories d’apprentissage formelles permettent de justifier logiquement le principe de l’induction, ce dernier assurant la fiabilité logique des méthodes. Cette proposition a été critiquée par Howson en 2011, ce dernier mettant en doute la possibilité même qu’une méthode puisse être logiquement fiable. Bien que Steel ait offert une réponse à cette critique, il n’y répond pas directement. Dans le présent article, (...) une réponse frontale à celle-ci est offerte en s’inspirant des pratiques de tests d’hypothèses en sciences biologiques. Pour ce faire, une règle de construction des ensembles d’hypothèses est proposée, règle offrant une justification logique au fait qu’une méthode convergera nécessairement vers la vérité. Cet amendement étant cohérent avec l’ensemble de la proposition de Steel, il est ainsi possible d’affirmer que sa thèse est renforcée par cette proposition. (shrink)

Though based on the historic interaction between Atlantic peoples, the Atlantic Civilization only became a reality after World War II with the East West conflict. It comprised a liberal economic order and democratic states, most of which were linked together in a military alliance and led by the United States. The system is now severely challenged by consequences of globalization and a revival of geopolitics, in particular Russia’s intervention in the Ukraine as well as terrorism and the rise of populism. (...) Its future depends on successfully dealing with the new threats to its central values. (shrink)

For centuries, herbarium specimens were the focus of exchange in global botanical networks. The aim was the ‘complete’ registration of the flora, for which ‘complete’ collections in botanical institutions worldwide were considered to be a necessary basis, although this ardently sought-after ideal was never achieved. The study of colonial plants became a special priority of botanical research in the metropolises. With knowledge of the many treasures of the plant world considered the key to securing wealth and power, political and economic (...) interests influenced both the organization and the subject matter of scientific research. After the German Reich began annexing colonies in the 1880s, legal regulations established Berlin's botanical institutions as the research centre on colonial flora. They also became a clearing house for plant material from overseas. Berlin-based curators selected duplicates of herbarium specimens from the German colonies, distributing them to other botanical institutions throughout Germany. More importantly, duplicates became a form of currency in trans-imperial networks, which relied on reciprocity. In exchange for duplicate German colonial herbarium specimens, the Berlin institutions received vast quantities of botanical samples from their British, Dutch, French and American counterparts. (shrink)

The growing number of cloned eukaryotic genes lacking a defined or proven biological function poses a major challenge in ‘reverse genetics’. A method is described here that permits efficient screening for new lesions in, or close to, genes corresponding to cloned DNA sequences of interest. The technique involves transposon mutagenesis, followed by screening of DNA isolated from a population of mutagenised individuals (or their progeny) for evidence that the population contains at least one individual in which transposon insertion has occurred (...) at the target locus. Detection of rare individuals within the population is facilitated by the use of the polymerase chain reaction (PCR). Once recognised, specific individuals (or their progeny) are isolated from the population by a process of sib‐selection. In cases where insertion of the transposon has occurred close to, but not within, the target locus, secondary events involving imprecise excision of the transposon will nonetheless allow the isolation of mutant individuals. Though the method was developed specifically for the transposon‐mutagenesis of Drosophila, extensions to other organisms and to other mutagenic strategies are feasible and some of the possibilities are discussed. (shrink)

Targeting of cell ablation agents under the control of tissue‐specific promoters promises to be an important tool for studies of development and function in higher organisms. Temperature‐sensitive cell ablation agents, recently developed for Drosophila, extend control to temporal as well as spatial aspects of toxin expression. Here we discuss achievements to date, together with a novel form of enhancer trap technology with the potential for driving toxin expression in a large range of cell types.