The aspects of Erhard Weigel's Analysis Aristotelica ex Euclide restituta that foreshadowed and helped form some characteristics of symbolic logic are highlighted: first, the idea of a pure form of a logical syllogism or of a mathematical proof and, second, a tentative arithmetisation of some aspects of logic. Also, Weigel's emphasis on the role of symbols and figures in the process of mathematical proof is discussed.

From the mid-1600s to the beginning of the eighteenth century, there were two main circles of German scholars which focused extensively on diagrammatic reasoning and representation in logic. The first circle was formed around Erhard Weigel in Jena and consists primarily of Johann Christoph Sturm and Gottfried Wilhelm Leibniz; the second circle developed around Christian Weise in Zittau, with the support of his students, particularly Samuel Grosser and Johann Christian Lange. Each of these scholars developed an original form of (...) using geometric diagrams in logic. In this paper, I will trace the historical notes of John Venn and other modern logicians back to the original works published in the Weigel and Weise circles and describe the development of using geometric figures for logical reasoning and representation in that period of time. (shrink)

Erhard Weigel (1625-1699), mathematician from Jena, developed within the context of his efforts for a mathematically oriented universal science and for a methodologically exact natural theology also a mathematical proof of God, which should prove God’s existence irrefutably and with the highest degree of certainty. Leibniz, as is known a disciple of Weigel himself, was already acquainted with the proof ’s earliest drafts from the 1670’s on and referred to almost all of Weigel’s publications on the proof (...) of God in his writings, which shows his never ceasing interest on this topic. The article presents the rationale of Weigel’s proof of God as well as the central aspects of Leibniz’s in part assenting while also in part critical considerations to it and gives an outlook on the importance of the topic for Leibniz’s own development. (shrink)

Between 1650 and 1664, a giant globe was created in Gottorf under Duke Friedrich III, which was widely known and marvelled at by many contemporaries as a wonder of the world. The scientific management of the project was the responsibility of the court mathematician and librarian Adam Olearius. The Gottorf Globe and its counterpart (a “Sphaera Copernicana”) presented the astronomical knowledge of the time in a pictorial form. The image of the earth and the cosmos was also intended to show (...) the Creator and his omnipotence. Erhard Weigel, professor of mathematics at the University of Jena from 1653, also constructed monumental globes. These baroque world models, as well as Robert Long’s 18th-century sphere, can be considered the precursors of today’s planetariums. (shrink)

The so-called war on terror has recently revived interest in the just-war tradition . George Weigel has played an important role in this renaissance, and his recent article on JWT has occasioned a new debate concerning its merits. At the heart of this debate is the nature of violence. Weigel holds that the JWT is not based on a presumption against violence, whereas his critics argue that it is. After critically summarizing Weigel’s position, I counter his divorcing (...) of the JWT from the presumption against violence. By looking closely at the terms used in the debate concerning this presumption, I show that violence, in the scholastic tradition that nurtured the JWT, is understood as disordered force. As disordered, violence is contrary to reason, and thus also to justice . If just war aims at order, it itself may not be disordered. Thus, I argue that the JWT is best described as a two-fold presumption against violence: a just war is waged to counter violence, and a just war may not itself use violence. Consequently, since the JWT, grasped as a presumption against violence, concludes the link between justice and ordered force as the link between end and means, it avoids abstract ethical intentionalism: the proper end of the just war, as opposed to a mere intention, dictates the means that it has at its disposal. (shrink)

Leibniz admet la thèse de la création continuée. Le but de cet article est de montrer les raisons pour lesquelles, à ses yeux, les tentatives de Descartes et de Weigel pour s’en servir comme preuve de l’existence de Dieu ont échoué et ce qui, dans sa propre métaphysique, empêche l’élaboration d’une démonstration pleinement satisfaisante sur son fondement. Il n’est pas sûr en effet que Leibniz soit parvenu à concilier parfaitement la nécessité de la dépendance permanente des créatures à l’égard (...) de leur créateur – qui requiert son action continuelle – et l’exigence de l’autonomie causale des substances finies. (shrink)

Der Mathematiker Erhard Weigel (1625-1699) gilt bisher als einer der bedeutendsten deutschen Vertreter der sog. "Fruehaufklärung". Dieser Band hinterfragt nun diesen traditionellen und deshalb allzu bequemen philosophiegeschichtlichen Begriff nach seiner Erklärungsfunktion innerhalb der modernen Wissenschaftsgeschichte. In komparatistischer Sicht auf die deutsche Universitätslandschaft nehmen die Beiträger den institutionellen Rahmen und seine konkreten Auswirkungen auf den Lehrbetrieb in den Blick, um die Bedingungen des damaligen Wissenschaftsverständnisses und seiner Entwicklungsrichtungen zu untersuchen. Im Fokus stehen die Verwandlungen der aristotelischen Basis des Wissenschaftsverständnisses und (...) was sich damalige Universitätslehrer als Autoren explizit (z.B. in Form wissenschaftstheoretischer Schriften und Lehrbuecher) oder implizit (z.B. in Form der von ihnen praktizierten Wissenschaft) unter Wissenschaft vorgestellt und ihrem gelehrten Publikum vermittelt haben. (shrink)

Logicians commonly speak in a relatively undifferentiated way about pre-euler diagrams. The thesis of this paper, however, is that there were three periods in the early modern era in which euler-type diagrams (line diagrams as well as circle diagrams) were expansively used. Expansive periods are characterized by continuity, and regressive periods by discontinuity: While on the one hand an ongoing awareness of the use of euler-type diagrams occurred within an expansive period, after a subsequent phase of regression the entire knowledge (...) about the systematic application and the history of euler-type diagrams was lost. I will argue that the first expansive period lasted from Vives (1531) to Alsted (1614). The second period began around 1660 with Weigel and ended in 1712 with lange. The third period of expansion started around 1760 with the works of Ploucquet, euler and lambert. Finally, it is shown that euler-type diagrams became popular in the debate about intuition which took place in the 1790s between leibnizians and Kantians. The article is thus limited to the historical periodization between 1530 and 1800. (shrink)

"Lest one think that the focus on aspect-seeing in Wittgenstein is only a means to more contemporary philosophical ends, one ought to read Day’s remarkable 'Wanting to Say Something: Aspect-Blindness and Language'. Day considers the issue of aspect-blindness, arguing that universal aspect-blindness is impossible for beings with language. Specifically, he shows that a child’s first attempt at language, at trying “bloh” for “ball,” is neither an indication that the child sees the ball for the first time, nor an indication that (...) the child is giving a first label for an object seen all along. Rather, he shows that this attempt is an indication of the dawning of an aspect. The dawning of aspects, so common during the phase of language acquisition, becomes supplanted by language itself. Universal aspect-blindness is not humanly possible, then. Day argues that the acquisition of language results in a loss of desire for aspects (which it is possible to regain through art). Localized aspect-blindness is familiar because as language-users, we have lost our desire for aspects. Day then turns to questions about the deep purpose behind Wittgenstein’s style. Why are those doubting voices prominent? Why does Wittgenstein demand so often that the reader answer his questions? Day shows that these elements of Wittgenstein’s style arise from a motivation to regain his own desire for aspects, and he wants to re-awaken our own desire for aspects. Day motivates us to consider aspect-seeing in order to see Wittgenstein himself anew." --Chris Weigel, Book Review of Seeing Wittgenstein Anew, Journal of the History of Philosophy 49:2 (April 2011): 263. (shrink)

Brecht's relationship to Marxism is extremely important and highly complex. From the 1920s until his death in 1956, Brecht identified himself as a Marxist; when he returned to Germany after World War II, he chose the German Democratic Republic (GDR), where his actress wife Helene Weigel and he formed their own theater troupe, the famed Berliner Ensemble, and were eventually given a state theater to run. Yet Brecht's relationship to orthodox Marxist officials and doctrine was often conflictual, and his (...) own work and life were highly idiosyncratic. Of a strongly anti-bourgeois disposition from his youth, the young Brecht was also initially repelled by Bolshevism. He experienced the German revolution of 1918 with some ambivalence and dedicated himself to literary and not political activity during the turbulent early years of the Weimar republic. He recorded in his Diaries, for example, a negative response to a talk he heard on 1920 on the Soviet Union in which he was repelled by the concept of socialist order he heard discussed. He indicated a negative impression of Bolshevism and conclude his entry by noting that he rather have a new car than socialism! (shrink)