Though accepting the traditional view that truth and falsity are properties of propositions and judgments, Leibniz does not refrain from predicating truth and falsity of pre-judgmental items such as ideas, which he considers to be true iff logically consistent, and false otherwise. Elsewhere, however, Leibniz claims that ideas are true or false only insofar as they include the (true or false) affirmation that their object is possible. This paper aims to cast light on Leibniz’s doctrine of ideas as truth-bearers by (...) exploring its historical background. On the one hand, Leibniz’s pronouncements reflect his reaction to the post-Cartesian debates. On the other hand, they appear to be inspired from Aquinas’s doctrine of accidental falsity. (shrink)

In his article, Florian Vermeiren attributes to Leibniz – like other interpreters before him – the distinction of two different kinds of relations: 1) relations in the proper sense of the word as, for example, the fatherhood subsisting between Sophroniscus and Socrates, which Leibniz considers situated ‘outside the subjects’ involved; 2) relational properties, such as being a father, inherent in Sophroniscus. The distinction is clearly present in Leibniz’s writings. According to Vermeiren, Leibniz considers ‘purely mental’ only the relations ‘out of (...) the subjects’ and not the relational predicates, by means of which, on the other hand, the individuals of the Leibnizian world would be truly related. In this sense, therefore, Leibniz would admit the reality of relations, which would play an important role in his ontology. At least since 1686 (the year in which he wrote the Discourse), however, Leibniz states that the world is made only of individuals with their internal modifications: just as there are no properties with a leg in one subject and a leg in another, there are no individuals bound together by any kind of material nexus or ‘real’ ties. Thus, if we make a list of all fathers on the one hand and sons on the other, there remains the problem of how to properly connect the fathers exactly with their sons. Attributing to each of two related individuals a relational property is not enough to connect them. Being a father in David must necessarily refer in some way to Solomon as a son. Leibniz is aware of this, as his attempts to analyze relational propositions in his essays on rational grammar show. Given the sentence ‘Cajus is killed by Titius’ for example, Leibniz attempts to reduce it to an inference between a pair of categorical sentences, each of which attributes a relational predicate to the subject. Relations (and relational properties) result from the substances and their modes, “without producing any change” of themselves but only in virtue of a consequence, that is of a logical inference. The image of the world derived so from the Monadology and other Leibnizian writings is that of a world composed of a collection of isolated individuals, independent of each other and lacking mutual connections. Relational properties correspond to internal modifications of each individual: the second term, in the case of binary relations (the ‘external’ one: Helen, if Paris loves Helen) is resolved into an internal representation (of Paris, in this case). It is God who coordinates the various representations of individuals with each other, to result in a harmonious whole. Since relations are a consequence of the existence of the individual substances with their intrinsic properties, God himself can be said to be the creator of relations, in so far as he calls the individuals into existence. And this is exactly what Leibniz states, in his commentary on Temmik’s book. (shrink)

The paper first examines the difference between Wolff’s demonstration of my present existence and Descartes’ intuitive connection of my thinking with my existence. The results of this investigation enable us to analyse two controversial answers to the question of the knowledge of existence in Wolff’s works. The first answer is from Jürgen Stolzenberg, who discusses Wolff’s proof of the statement: I am. The second is written by Luigi Cataldi Madonna, who investigates the concept of contingent existence in Wolff’s works. The (...) problems of the interpretations they propose are different. The first uses in his analysis meanings of central terms that were foreign to Wolff. The second does not pay attention to Wolff’s framework and aims. These difficulties in their interpretations distort what Wolff does and plans in his treatment of the knowledge of existence. Wolff builds a demonstration to prove how we know that we are, because for Wolff there is only science if we prove all that we claim. According to him, philosophy is a science. With this paper I plan to clarify the context of Wolff’s demonstration of my present existence as well as the demonstration itself, to which the analysis of the above two interpretations can contribute. (shrink)

This paper challenges Mugnai’s conceptualist reading of Leibniz’s theory of relations. I specifically question his idea that relational accidents are mental additions to absolute foundations. I examine some of the evidence on which he relies. Most importantly, I question his interpretation of Leibniz’s rejection of purely extrinsic denominations (abbreviated “NPED”) as stating that relations result from non-relational foundations. Mugnai thereby understands Leibniz’s notion of ‘extrinsic’ as ‘relational’ or ‘relative’. Such a reading contradicts both Leibniz’s definition of ‘extrinsic denominations’ and the (...) scholastic meaning of this notion. Furthermore, Leibniz’s use of NPED shows that some relations are intrinsic denominations. Additionally, I argue that conceptual relations cannot do all the work in Leibniz’s metaphysics. Fundamental notions such as expression, order and, most importantly, coexistence rely on non-conceptual relations. (shrink)

This article is written in the memory of Marcelo Dascal, and is conceived as an imaginary answer to a question put by him to the author: what is the point – given a shared non-religious, even atheistic, outlook – in translating (into the Hebrew) of Leibniz’s Théodicée? The two main theses of this imagined answer are: 1. That there is in the Théodicée a moral theory, partly implicit but irreducible and relatively independent of its theological content, and that this theory (...) is based on a paradoxical – but original and important – concept of moral necessity, extracted from the theory of the absolute need to choose the best possible; 2. That this concept of moral necessity may be developed into a theory of responsibility, looking back to the need to give accounts about what has been done (or not done), and forward, to what has to be done (or not) now. (shrink)

In early modern times, solar eclipses were feared events that gave rise to much astrological speculation, even though these events could already be predicted long in advance. Around 1700, the situation was already different. Astrology had lost its status as a science and had largely been pushed out of the universities. On the other hand solar eclipses had become very important for cartography. From the beginning and end times of the eclipse at different locations, the differences of their geographical coordinates (...) could be calculated. The changed situation can be illustrated perfectly by the eclipses of August 12, 1654 and May 12, 1706. Whereas in 1654 there were still many astrologically influenced warnings, in 1706 there was great calm in this respect, and instead numerous astronomers tried to record the event correctly and compare their results with those of other observers. (shrink)

With an overview of the most important scientific innovations in 17th century Europe as a background, the focus is on the field of astronomy and its distinction from astrology. The essays collected in this volume are situated within this development of the early modern period.

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)

We discuss the astronomical underpinning of the improved calendar of 1700. Starting from the astronomical motivation of the Gregorian calendar of 1582 and the rejection of this reform in Protestant states in Europe, we describe how the astronomical Easter reckoning based on Kepler’s Rudolphine tables led to the foundation of Berlin Observatory and enabled the founding of the Electoral Brandenburg Society of Sciences, which had to finance itself through a calendar monopoly.