Logical frameworks for analysing the dynamics ofinformation processing abound [4, 5, 8, 10, 12, 14, 20, 22]. Some of these frameworks focus on the dynamics of the interpretation process, some on the dynamics of the process of drawing inferences, and some do both of these. Formalisms galore, so it is felt that some conceptual streamlining would pay off. This paper is part of a larger scale enterprise to pursue the obvious parallel between information processing and imperative programming. We demonstrate that (...) logical tools from theoretical computer science are relevant for the logic of information flow. More specifically, we show that the perspective of bare logic [13, 18] can fruitfully be applied to the conceptual simplification of information flow logics. Part one of this program consisted of the analysis of 'dynamic interpretation' in this way, using the example of dynamic predicate logic ; the results were published in . The present paper constitutes the second part of the program, the analysis of 'dynamic inference'. Here we focus on Veltman’s update logic . Update logic is an example of a logical framework which takes the dynamics of drawing inferences into account by modelling information growth as discarding of possibilities. This paper shows how information logics like update logic can fruitfully be studied by linking their dynamic principles to static 'correctness descriptions'. Our theme is exemplified by providing a sound and complete HoarelPratt style deduction system for update logic. The Hoare/Pratt correctness statements use modal propositional dynamic logic as assertion language and connect update logic to the modal propositional logic S5. The connection with S5 provides a clear link between the dynamic and the static semantics of update logic. The fact that update logic is decidable was noted already in ; the connection with S5 provides an alternative proof. The S5 connection can also be used for rephrasing the validity notions of update logic and for performing consistency checks. In conclusion, it is argued that interpreting the dynamic statements of information logics as dynamic modal operators has much wider applicability. In fact, the method can be used to axiomatize quite a wide range of information logics. (shrink)
In this paper we present a dynamic assignment language which extends the dynamic predicate logic of Groenendijk and Stokhof [1991: 39–100] with assignment and with generalized quantifiers. The use of this dynamic assignment language for natural language analysis, along the lines of o.c. and [Barwise, 1987: 1–29], is demonstrated by examples. We show that our representation language permits us to treat a wide variety of donkey sentences: conditionals with a donkey pronoun in their consequent and quantified sentences with donkey pronouns (...) anywhere in the scope of the quantifier. It is also demonstrated that our account does not suffer from the so-called proportion problem.Discussions about the correctness or incorrectness of proposals for dynamic interpretation of language have been hampered in the past by the difficulty of seeing through the ramifications of the dynamic semantic clauses (phrased in terms of input-output behaviour) in non-trivial cases. To remedy this, we supplement the dynamic semantics of our representation language with an axiom system in the style of Hoare. While the representation languages of barwise and Groenendijk and Stokhof were not axiomatized, the rules we propose form a deduction system for the dynamic assignment language which is proved correct and complete with respect to the semantics. (shrink)
Logical frameworks for analysing the dynamics of information processing abound [4, 5, 8, 10, 12, 14, 20, 22]. Some of these frameworks focus on the dynamics of the interpretation process, some on the dynamics of the process of drawing inferences, and some do both of these. Formalisms galore, so it is felt that some conceptual streamlining would pay off.This paper is part of a larger scale enterprise to pursue the obvious parallel between information processing and imperative programming. We demonstrate that (...) logical tools from theoretical computer science are relevant for the logic of information flow. More specifically, we show that the perspective of Hoare logic [13, 18] can fruitfully be applied to the conceptual simplification of information flow logics. (shrink)
In 1889 Hugo de Vries published " Intracellular Pangenesis " in which he formulated his ideas on heredity. The high expectations of the impression these ideas would make did not come true and publication was negated or reviewed critically. From the reactions of his Dutch colleagues and the discussion with the famous German zoologist August Weismann we conclude that the assertion that each cell contains all hereditary material was controversial and even more the claim that characters are inherited independently (...) of each other. De Vries felt that he had to convince his colleagues of the validity of his theory by providing experimental evidence. He established an important research program which resulted in the rediscovery of Mendel's laws and the publication of "The Mutation Theory." This article also illustrates some phenomena that go beyond an interesting episode in the development of theories of heredity. It shows that criticism from colleagues can move a researcher so deeply that he feels compelled to set up an extensive research program. Moreover it illustrates that it is not unusual that a creative scientist is only partially willing to take criticism on his theories into account. Last but not least it demonstrates that common opinion on the validity of specific arguments may change in the course of time. (shrink)
It is argued that Hugo de Vries's conversion to Mendelism did not agree with his previous theoretical framework. De Vries regarded the number of offspring expressing a certain character as a hereditary quality, intrinsic to the state of the pangene involved. His was a shortlived conversion since after the ‘rediscovery’ he failed to unify his older views with Mendelism. De Vries was never very much of a Mendelian. The usual stories of the Dutch ‘rediscovery’ need, therefore, a (...) considerable reshaping. (shrink)
Hugo de Vries claimed that he had discovered Mendel's laws before he found Mendel's paper. De Vries's first ratios, published in 1897, for the second generation of hybrids were 2/3:1/3 and 80%:20%. By 1900, both of these ratios had become 3:1. These changing ratios suggest that as late as 1897 de Vries had not discovered the laws, although he asserted, from 1900 on, that he had found the laws in 1896. An Appendix details de Vries's Mendelian (...) experiments as described in the original edition of volume two of Die Mutationstheorie, but omitted entirely from the English translation. (shrink)
Recent studies have shown that Hugo de Vries did not rediscover Mendel's laws independently and that the classical story of the rediscovery of Mendel is largely a myth. Until now, however, no satisfactory account has been provided of the background and development of de Vries' views on heredity and evolution. The basic tenets of de Vries' Mutationstheorie and his conception of Mendelism are still insufficiently understood. It has been suggested that de Vries failed to assimilate Mendelism (...) and that he wrote his Mutationstheorie in a state of confusion. In this paper I argue that we can arrive at a better understanding by adopting a more symmetrical approach. My analysis will concentrate on three important aspects of de Vries' thinking which have been insufficiently appreciated until now. The first is that de Vries' reading of Mendel compelled him to change his conception of the hereditary particles, the pangenes, in a fundamental way. The second is de Vries' use of the notion of ‘hereditary force’. The third revolves around de Vries' typological species concept, which has been the source of much confusion in the literature. I shall conclude that de Vries did succeed in incorporating ‘Mendelism’ into his wider views on heredity and evolution, and that he did manage to handle his evidence in a consistent way. Yet I shall also conclude that Mendelism, in de Vries' interpretation, had nothing to do with ‘normal’ heredity and was mainly a laboratory phenomenon. (shrink)
De Vries' mutation theory has not stood the test of time. The supposed mutations of Oenothera were in reality complex recombination phenomena, ultimately explicable in Mendelian terms, while instances of large-scale mutations were found wanting in other species. By 1915 the mutation theory had begun to lose its grip on the biological community; by de Vries' death in 1935 it was almost completely abandoned. Yet, as we have seen, during the first decade of the present century it achieved (...) an enormous popularity. As this paper has tried to suggest, one of the principal reasons for this was that de Vries' theory served as a banner around which a whole crowd of disaffected Darwinians or anti-Darwinians could rally. However, not all of those who favored de Vries did so for quite the same reasons. Underlying the multitude of views ran several common threads: a dissatisfaction with current Darwinian theory born out of misunderstanding natural selection, a general misunderstanding of the nature of species, and a prejudice against speculative, nontestable theories in biology.Supporters of de Vries were not the only opponents of Darwinism, nor was the mutation theory the only alternative to natural selection. In the early twentieth century a number of theories had been proposed to explain away the problems which Darwin had left unsolved. There was the idea of orthogenesis, championed by the American paleontologists Cope, Osborn and others; organic selection (or orthoplasy) was championed by M. M. Baldwin and C. Lloyd Morgan; there were the concepts of convergent evolution proposed by Hermann Friedmann, the theory of physiological selection by John George Romanes, and the concepts of reproductive divergence by H. M. Vernon. Virtually none of these men either accepted or were strong supporters of the de Vriesian theory, for each had his own particular ‘ism” to advocate as the major factor in evolution. The existence of a large number of such theories, each purporting to be the explanation, was characteristic of evolutionary theory at the turn of the century. It is to a large extent the emphasis on such fragmentary concepts that retarded development of the comprehensive theory of evolution which emerged in the 1920's and 1930's. For the historian, however, a study of these alternative theories is instructive in trying to understand the inherent difficulties which Dawwinian theory posed to biologists at the time. De Vries' mutation theory serves historically as a mirror to reflect the critical mood of a generation hostile to the theory of natural selection.It has often been claimed that it was impossible to understand the mechanism of natural selection until it could be placed in genetic and mathematical terms. It is certainly true that great strides have been made in population genetics and the treatment of evolutionary concepts with mathematical tools in the last forty years. But the very people who developed the genetical and mathematical approach to evolution were already convinced of the essential correctness of Darwinian theory before they started. Advances in an understanding of Mendelian heredity aided greatly in solving one important issue for evolutionists: the origin of variations. And the rigor with which selection acted could best be studied by observing changes in gene frequencies (calculated mathematically) over a number of generations. But as this paper has shown, two of the basic problems which biologists faced in evaluating Darwinian theory at the turn of the century-the nature of species, and the criteria of what constituted an acceptable explanation in biological science-could not be answered directly by mathematics. What mathematical and genetical theory did do was to help convince the skeptics of the validity of the Darwinian proposition.The change in explanatory criteria which many hailed as de Vries' most important contribution to evolutionary theory seems to have been part of a general emergence of twentieth-century biology from the domination of theorizers in the nineteenth. It also marked the emergence of America from the domination of biological, and particularly evolutionary, influence of Europeans. The change occurred in three areas: in the kinds of questions asked: testable versus non-testable; in the kind of data sought: quantitative versus qualitative; and in the kinds of theories proposed: analytical and reductive—the attempt to see complex processes in terms of simpler components-as opposed to synthetic and speculative. Although ultimately wrong in his idea, de Vries and his theories rode high on the wave of “experimentalism” which was the harbinger of a new era in evolutionary theory. (shrink)
A great deal is known about the technical issues surrounding the introduction of Hugo De Vries's mutation theory and the subsequent development of the modern genetical theory of natural selection. But so far little has been done to relate these events to the wider issues of the time. This article suggests that extra-scientific factors played a significant role, and substantiates this by comparing De Vries's respect for the original Darwinian spirit with Thomas Hunt Morgan's use of the mutation (...) theory as part of an attack on the whole philosophy of Darwinism. In particular, it is argued that Morgan's attitude was dictated by his moral objections to the picture of a world dominated by struggle. (shrink)
The Dutch philosopher of religion Hent de Vries has explored and complicated the boundaries between religion and modern thought in order to create the space for an innovative “minimal theology.” This article reconstructs de Vries's interpretation of the changes in Theodor W. Adorno's thought between Dialectic of Enlightenment and Negative Dialectics in order to demonstrate its fecundity for a philosophical account of otherness. It also examines and defends de Vries's own rhetorical mode of reading texts as an (...) exemplary approach to philosophical dialogue. Finally, however, the essay challenges de Vries's privileging of the religious as the site of ethical relationality and his intentional bracketing of Adorno's critical social theory. (shrink)
The almost simultaneous and overlapping discoveries of Mendel's forgotten work by Hugo de Vries, Carl Correns, and Erik von Tschermak gave rise to an intense rivalry, some jealousy, and more than a little illfeeling. De Vries, the first to announce the discovery, has been subjected to the charge that he wished to conceal his discovery and to obtain for himself the credit for having discovered what we now call Mendelism. This charge involves the statement that de Vries (...) gave credit to Mendel only after he had found that others had also read Mendel's papers. The evidence on which this charge is based is sketchy, and we can now show that at least that portion of it that is based on supposed alteration in the proof of de Vries' paper in the Berichte is without foundation. Unfortunately, de Vries gave three different accounts of how he was led to Mendel's work. Two of these involve Liberty Hyde Bailey.Bailey had listed Mendel's papers in a bibliography that he published in 1892 in The Rural Library. Bailey did not include this bibliography in the first edition (1895) of Plant Breeding or in its reprinting in 1896 and 1897. He did include the bibliography in the second edition (1902), but this was after de Vries and others had called attention to Mendel. In 1899, both Bailey and de Vries gave papers at the Hybrid Conference held at Chiswick, England, but we have no record of their having discussed Mendel. What evidence we have indicates that, at this time, neither of them had read Mendel's papers.De Vries wrote to Bailey that it was Bailey's listing of Mendel in the bibliography published in The Rural Library that led to his discovery of Mendel. Later, de Vries wrote to H. F. Roberts that he had first found a reference to Mendel in Bailey's Plant Breeding of 1895, where the bibliographic reference to Mendel's papers was not published. Finally, de Vries told Th. J. Stomps, who succeeded him at the University of Amsterdam, that he had first learned of Mendel early in 1900 from a reprint of Mendel's paper sent him by his friend Professor M. W. Beyerinck. Our present evidence favors Stomp's account as it shows that de Vries had not read Mendel's papers in 1899 but had early in 1900.Attempts to pinpoint de Vries' discovery of Mendel are aided in part, and in part confused, by the fact that he published five relevant papers in 1900. These papers were in press simultaneously, and some of them were altered in proof. Further confusion is due to the fact that at least three of them were published in the reverse order of their acceptance for publication. Unfortunately we do not have the crucial dates for all of the papers.J. Roy. Hort. Soc. 24: 69–75. A definitely pre-Mendelian paper given on 11 July 1899, and published in 1900 (possibly in April). The evidence for an alteration in proof after de Vries had read Mendel is shown by the fact that de Vries described a ratio of 99 to 54 as a 3 to 1 ratio.Rev. gén. botan. 12: 129–137. A Mendelian paper, giving the 3 to 1 ratio in the F2 generation of a cross between starchy and sugary corn. The paper is not dated by de Vries but it was published in the volume, 128 pages ahead of a paper de Vries dated 19 March. In a footnote, de Vries cites a paper by Correns that was published on 25 January, so we can tell that it was written or corrected in proof after this date. Here Correns showed de Vries that he had already read Mendel's paper. Any attempt by de Vries to ignore Mendel or get credit for Mendelism after 25 January would have been senseless. This date was nearly two months before de Vries' Berichte paper was submitted for publication.Ber. deut. botan. Ges. 18: 83–90. Accepted for publication 14 march, published 25 April. This paper gives Mendel full credit and stimulated the publications of Correns and von Tschermak. As de Vries was aware that Correns already knew of Mendel when the paper was first submitted, there was no occasion to alter it in proof.Rev. gén. botan. 12: 257–271. Dated by de Vries 19 March, but the proof was read after June. De Vries cites von Tschermak's paper in the Berichte that was published in June. The Revue paper is a Mendelian paper, and Mendel is cited on the last page.C. R. Acad. Sci. (Paris) 130: 845–847. Accepted for publication 26 March 1900. Reprint received by Correns 21 April. Mendel is not mentioned but de Vries' use of terms told Correns that de Vries had read Mendel's paper. First of the papers to be published, it caused Correns to assume that de Vries wanted the credit that was due Mendel.The three discoverers of Mendel did not form a mutual admiration society. (shrink)
It is argued that de Vries did not see Mendel's paper until 1900, and that, while his own theory of inheritance may have incorporated the notion of independent units, this pre-Mendelian formulation was not the same as Mendel's since it did not apply to paired hereditary units. Moreover, the way in which the term ‘segregation’ has been applied in the secondary literature has blurred the distinction between what is explained and the law which facilitates explanation.
This note discusses lecture plates at the Hugo de Vries Laboratorium that may be relevant to Hugo de Vries's claim to have independently discovered Mendel's law of segregation. Dating when the plates were made is problematic.
Traveling-wave solutions of the standard and compound form of Korteweg–de Vries–Burgers equations are found using factorizations of the corresponding reduced ordinary differential equations. The procedure leads to solutions of Bernoulli equations of non-linearity 3/2 and 2 (Riccati), respectively. Introducing the initial conditions through an imaginary phase in the traveling coordinate, we obtain all the solutions previously reported, some of them being corrected here, and showing, at the same time, the presence of interesting details of these solitary waves that have (...) been overlooked before this investigation. (shrink)
In this paper we study computability of the solutions of the Korteweg-de Vries equation ut + uux + uxxx = 0. This is one of the open problems posted by Pour-El and Richards . Based on Bourgain's new approach to the initial value problem for the KdV equation in the periodic case, we show that the periodic solution u of the KdV equation is computable if the initial data is computable.
One of the lecture plates in the collection of the Museum of the University of Amsterdam, generally believed to be used by the Dutch botanist Hugo de Vries, has aroused much discussion in relation to the question of whether or not de Vries knew Mendel's laws before he published his rediscovery of them in 1900. The plate suggests that de Vries observed Mendelian segregation ratios in 1895 and 1896 in the progeny of a cross of two varieties (...) of Papaver with different flower colour. According to his own account, it was through this cross that he first deduced the laws of Mendel in 1896. Some researchers have accepted the lecture plate as proof for this claim. My conclusion is that the plate was not made before 1900 but in 1904 for a lecture course in the USA and, as a consequence, that it is not a contemporary piece of evidence. A closer look at the descriptions of the depicted experiment in de Vries' publications revealed that its original goal was not to investigate segregation but to transfer a monstrosity. The segregation of the flower colour was a accidental event. No research notes of the experiment have survived, but a note on an experiment with Veronica, performed in the same successive years as the Papaver experiment and definitely intended to investigate the segregation of flower colour, shows that this experiment was interpreted in a theoretically conceived, more or less Mendelian way. Because of a sloppy performance, no firm conclusions could be drawn from the experiment, but de Vries clearly had the idea of Mendelian segregation in 1896. That he never brought it up before 1900 suggests that he could not establish the general validity of segregation rules, as is shown in the case of Veronica. The reading of Mendel's paper in 1900 immediately put an end to de Vries' doubts. He scrapped the failures and kept the successes, proudly presenting these to the public as proof for the laws of segregation and, at the same time, of the independence of his discovery. (shrink)
Locke has often been hailed as the father of an empiricism that provided a philosophical basis to natural science in the Age of Enlightenment. In this article his empiricism is compared with that of the little known Dutch Aristotelian professor Gerardus de Vries. There are striking parallels between Locke's brand of mechanist empiricism and the pragmatic and flexible Aristotelianism of De Vries. These parallels put strictures on both the archaic character of the Aristotelianism embraced by De Vries (...) and on the modern and forward-looking character of Locke's philosophy of science. (shrink)
El artículo desarrolla una hermenéutica fenomenológica de las relaciones entre historia, sentido, existencia y eternidad en la filosofía de la historia de Jan Pato¹ka. Primero determina las nociones de sentido e historia. Luego explicita en qué medida la existencia humana constituye la condición de posibilidad de un sentido problemático y concurrente de la historia. Finalmente analiza la �existencia en la verdad� como resultado de una correlación entre existencia y eternidad y comprende la interpelación de la eternidad como origen del sentido.
In this paper we seek to take notice of the evolution and continuity of Jan Patočka’s phenomenology on the topic of the world and human existence’s relationship with it. We believe that this problem underlies and stimulates Patočka’s whole phenomenological research and we think that it is a key element to understand the ensemble of his thought.
Le phénoménologue tchèque Jan Pato?ka, auteur d?une phénoménologie asubjective défendant la thèse d?un procès asubjectif de l?apparaître (d?une autonomie du phénomène par rapport à l?ego), a accordé au problème des relations nécessaires et difficiles que la philosophie entretient en son sein même avec la littérature une attention particulière qui l?a conduit à poser les fondements d?une phénoménologie de la littérature centrée autour de l?idée d?un asubjectivisme de l?écrivain. Nous suivrons ici deux axes de réflexion connexes: premièrement, nous montrerons pourquoi et (...) comment Pato?ka restaure le vocabulaire et la vision de l?homme propres au mythe et reprend ce qu?il aperçoit comme le fondement de la tragédie pour élaborer une nouvelle compréhension du phénomène de l?existence comme mouvement. Deuxièmement, nous décrirons le rôle que joue l?écrivain moderne à une époque marquée par la fragmentation de la vie. Car l?écrivain qui édifie une ?littérature métaphysique? a le privilège, selon Pato?ka, d?être ?l?administrateur propre et originel de l?intégralité de la vie et de la totalité universelle?, il est ainsi une sorte de ?quasi-phénoménologue? dont la philosophie ne peut se passer si elle veut saisir ces phénomènes qui, sans être purement et simplement subjectifs, ne peuvent néanmoins être réduits à l?objectivité du concept. (shrink)
L?intention de cet article est de présenter la critique et le remaniement de l?intentionnalité qu?implique l?élaboration d?une phénoménologie asubjective chez Jan Pato?ka. À cette fin, nous exposerons d?abord les raisons qui amènent Pato?ka à prendre ses distances par rapport au subjectivisme de la phénoménologie husserlienne, et les conséquences de ce dépassement de l?horizon transcendantal de la subjectivité. Et dans un deuxième temps nous tâcherons de suivre les implications de cette destitution du subjectivisme relativement au statut et au sens de l?intentionnalité. (...) La nécessité d?élaborer une phénoménologie asubjective et de proposer par là une alternative au subjectivisme et à l?idéalisme implicite de la phénoménologie husserlienne découle chez Pato?ka d?une volonté de rendre compte plus authentiquement, c'est-à-dire plus phénoménologiquement, de la structure et de la modalité de l?apparaître. En effet, c?est en s?interrogeant sur le comment de l?apparaître que Pato?ka est conduit à affirmer que celui-ci ne peut pas être expliqué à partir d?un sujet qui, avant tout, est lui-même quelque chose d?apparaissant. S?il apparaît à son tour, c?est qu?il est soumis lui-même à la légalité de l?apparaître, au lieu d?en être le principe. À partir de ces considérations, il devient possible de formuler une alternative tranchée entre deux types de phénoménologie, comme le. (shrink)
Il y a comme un hiatus entre le titre et le sous-titre de ce livre. Le titre, Aux origines de l'action sociale, annonce une intention modeste ; en effet l'ouvrage, composé de touches successives, ne se présente pas comme une synthèse historique organisée. Par contre le sous-titre indique un projet précis et construit, un projet d'histoire : L'invention des services sociaux aux chemins de fer. Dans le texte tout se passe comme si les auteurs n'avaient pas voulu (pas su ?) (...) choisir entre .. (shrink)
Cher*** Je rentre à l'instant des « Iles d'Auvergne », d'où mon silence de ces dernières semaines. La traversée, avec « Gevaudan Airline », ne s'est pas faite sans péripéties. Je m'étendrai, sous peu, sur l'installation pilote « dénouée, déliée, déroulée, dressée » que j'ai pu élever là-bas, et dont je te donne un aperçu ci-dessous. Mais tu voudras bien, avant cela me suivre brièvement dans les étranges fantasmagories qui hantent mon avance vers l'été. « Les chiens de fer » (...) A l'approche d'Avignon, autour de - Résidence numérique — François Villais. (shrink)
Pour appréhender le costume en archéologie protohistorique européenne, il faut le plus souvent se satisfaire des accessoires vestimentaires métalliques conservés dans les sépultures, tels que les fibules et les éléments de ceinture. Cette nature instable des vestiges limite notre compréhension de l’implication du costume dans la construction sociale des différences entre les individus des ensembles funéraires. Néanmoins, l’examen des éléments métalliques de ceinture permet d’avoir une image dynamique de l’emploi de ces objets dans la représentation et la création de ces (...) différences, qui ne reposent pas nécessairement sur une dualité entre des ensembles sépulcraux dits « masculins » ou « féminins ». La ceinture doit être investie d’une signification symbolique particulière pour devenir un objet participant à la structuration des différences entre les genres. (shrink)