Multicellular organisms are ensembles of quasi-two-dimensional structures (sheets) of various kinds. Why should the development of all organisms be mediated by a quasi-two-dimensional structure? Why does such development avoid a direct confrontation with the third dimension? In this paper, we accept the challenge of addressing this question from the perspective of computational geometry and suggest that the construction of three-dimensional organisms may be explained by the constraints imposed on a bottom-up construction process.
Nicolas Claude Fabri de Peiresc gilt als Entdecker des Orion-Nebels . Als solcher ist er seit neunzig Jahren bekannt. Der französische Astronom und Wissenschaftshistoriker Guillaume Bigourdan zog diesen Schluss aus Aufzeichnungen, die er in Peirescs unveröffentlichtem Journal des observations entdeckt und 1916 veröffentlicht hatte. Demnach soll Peiresc den Orion-Nebel im November 1610 beobachtet haben. Peirescs Zeitgenossen jedoch war diese Beobachtung verborgen geblieben, und niemandem sonst gelang sie so früh nach Einführung des Teleskops. Mittlerweile sind Zweifel an Peirescs Entdeckung (...) angemeldet worden. Die von Bigourdan veröffentlichten Notizen sind bislang keiner eingehenden Prüfung unterzogen worden. Der vorliegende Aufsatz liefert eine neue Transkription sowie erstmals eine Übersetzung der lateinischen Handschrift. Im Vergleich dazu erweist sich die Bigourdansche Edition häufig als nicht korrekt. Peirescs Orion-Bericht, der hier erstmals in Gänze lesbar vorliegt, wirft neue Fragen auf. Denn aus ihm geht nicht hervor, welche Region im Sternbild Orion, welche Sterne und welche Nebelobjekte Peiresc 1610 beobachtete. Die vollständige Lektüre von Peirescs Notizen verlangt nach einer neuen Interpretation seiner Beobachtungen im Sternbild Orion. Nur so ließe sich klären, ob tatsächlich schon Peiresc den Orion-Nebel sehen konnte oder ob womöglich M42 erst später sichtbar wurde.SummaryNicolas Claude Fabri de Peiresc is seen as the first to have discovered the Orion nebula in 1610. Peiresc's discovery remained completely unknown until it was brought to light by the French astronomer and historian of science, Guillaume Bigourdan, in 1916. Besides Peiresc, however, nobody else is known to have seen M42 so early in the seventeenth century. Doubts have been raised about Peiresc's discovery. Curiously enough, the passages from Peiresc's Journal published in 1916 have neither been thoroughly interpreted nor translated yet. The following article presents a new transcription of Peiresc's manuscript notes on Orion as well as a German and an English translation of the Latin text. When comparing the manuscript of Peiresc's Journal with Bigourdan's transcription, it becomes clear that Bigourdan has not reproduced the Latin text correctly. The content itself raises questions about the nature of Peiresc's observation. One cannot tell with certainty what region of Orion or what stars or nebular objects Peiresc was actually observing. From rereading Peiresc's notes, it becomes clear that a new interpretation is needed in order to determine if he could already see the Orion nebula in 1610 or if the Orion nebula appeared later in the seventeenth century. (shrink)
_ Source: _Volume 24, Issue 2, pp 300 - 317 This article examines R. Zvi Yehudah Kook’s reading of two earlier thinkers who were influential in the formulation of his thought—the Maharal of Prague and R. Avraham Azulai. I argue that his creative and unique reading of these texts exemplifies a fascinating dialogue he held with earlier sources, which he interpreted and infused with his own theological postulates. Here I explore his theory of the unique nature of the Jewish soul, (...) in both its collective and individual manifestations. The connection between R. Zvi Yehudah’s approach to interpreting earlier Jewish theological texts and that of his father, R. Avraham Itzhak HaCohen Kook, will also be discussed. (shrink)
This book offers a rigorous, concise, and nontechnical introduction to some of the fundamental insights of rational choice theory. It draws on formal theories of microeconomics, decision making, games, and social choice, and on ideas developed in philosophy, psychology, and sociology. Itzhak Gilboa argues that economic theory has provided a set of powerful models and broad insights that have changed the way we think about everyday life. He focuses on basic insights of the rational choice paradigm--the general conceptualization rather (...) than a particular theory--that survive recent critiques of economic theory's various failures. Gilboa explains the main concepts in language accessible to the nonspecialist, offering a nonmathematical guide to some of the main ideas developed in economic theory in the second half of the twentieth century. Chapters cover feasibility and desirability, utility maximization, constrained optimization, expected utility, probability and statistics, aggregation of preferences, games and equilibria, free markets, and rationality and emotions. Online appendixes offer additional material, including a survey of relevant mathematical concepts. (shrink)
In his exciting and original view of the universe, Itzhak Bentov has provided a new perspective on human consciousness and its limitless possibilities. Widely known and loved for his delightful humor and imagination, Bentov explains the familiar world of phenomena with perceptions that are as lucid as they are thrilling. He gives us a provocative picture of ourselves in an expanded, conscious, holistic universe. _.
Economic theory reduces the concept of rationality to internal consistency. As far as beliefs are concerned, rationality is equated with having a prior belief over a “Grand State Space”, describing all possible sources of uncertainties. We argue that this notion is too weak in some senses and too strong in others. It is too weak because it does not distinguish between rational and irrational beliefs. Relatedly, the Bayesian approach, when applied to the Grand State Space, is inherently incapable of describing (...) the formation of prior beliefs. On the other hand, this notion of rationality is too strong because there are many situations in which there is not sufficient information for an individual to generate a Bayesian prior. It follows that the Bayesian approach is neither sufficient not necessary for the rationality of beliefs. (shrink)
This note argues that, under some circumstances, it is more rational not to behave in accordance with a Bayesian prior than to do so. The starting point is that in the absence of information, choosing a prior is arbitrary. If the prior is to have meaningful implications, it is more rational to admit that one does not have sufficient information to generate a prior than to pretend that one does. This suggests a view of rationality that requires a compromise between (...) internal coherence and justification, similarly to compromises that appear in moral dilemmas. Finally, it is argued that Savage's axioms are more compelling when applied to a naturally given state space than to an analytically constructed one; in the latter case, it may be more rational to violate the axioms than to be Bayesian. (shrink)
Coordination games often have multiple equilibria. The selection of equilibrium raises the question of belief formation: how do players generate beliefs about the behavior of other players? This article takes the view that the answer lies in history, that is, in the outcomes of similar coordination games played in the past, possibly by other players. We analyze a simple model in which a large population plays a game that exhibits strategic complementarities. We assume a dynamic process that faces different populations (...) with such games for randomly selected values of a parameter. We introduce a belief formation process that takes into account the history of similar games played in the past, not necessarily by the same population. We show that when history serves as a coordination device, the limit behavior depends on the way history unfolds, and cannot be determined from a-priori considerations. (shrink)
Gilboa and Schmeidler provide a paradigm for modelling decision making under uncertainty. Unlike the classical theory of expected utility maximization, case-based decision theory does not assume that decision makers know the possible 'states of the world' or the outcomes, let alone the decision matrix attaching outcomes to act-state pairs. Case-based decision theory suggests that people make decisions by analogies to past cases: they tend to choose acts that performed well in the past in similar situations, and to avoid acts that (...) performed poorly. It is an alternative to expected utility theory when both states of the world and probabilities are neither given in the problem nor can be easily constructed. The authors describe the general theory and its relationship to planning, repeated choice problems, inductive inference, and learning; they highlight its mathematical and philosophical foundations and compare it with expected utility theory as well as with rule-based systems. (shrink)
This paper examines the interrelations between astronomical images of nebulae and their observation. In particular, using the case of the ‘Great Spiral’ , we follow this nebula beginning with its discovery and first sketch made by the third Earl of Rosse in 1845, to giving an account, using archival sources, of exactly how other images of the same object were produced over the years and stabilized within the record books of the Rosse project. It will be found that a particular (...) ‘procedure’ was employed using ‘working images’ that interacted with descriptions, other images and the telescopic object itself. This stabilized not only some set of standard images of the object, but also a very potent conception of spirality as well, i.e. as a ‘normal form’. Finally, two cases will be contrasted, one being George Bond's application of this spiral conception to the nebula in Orion, and the other Wilhelm Tempel's rejection of the spiral form in M51. (shrink)
In recent years the understanding of the cognitive foundations of economic behavior has become increasingly important. This volume contains contributions from such leading scholars as Adam Brandenburger, Michael Bacharach and Patrick Suppes. It will be of great interest to academics and researchers involved in the field of economics and psychology as well as those interested in political economy more generally.
It is argued that, contrary to a rather prevalent view within economic theory, rationality does not imply Bayesianism. The note begins by defining these terms and justifying the choice of these definitions, proceeds to survey the main justification for this prevalent view, and concludes by highlighting its weaknesses.
This unique longitudinal study examines the state of work centrality and other life areas in Israel among the same individuals over a 12-year period. A new representative sample of the Israeli labour force in 1992–93 assists us in exploring whether the changes occurred by cohort, life course or period effect. The restudied sample maturation led to a decrease in the importance of leisure, while the importance of work, family, community and religion remained stable. The increase of work centrality between the (...) 1980s and the 1990s was found to be influenced by period effect; there was no evidence of a life course or cohort effect on work centrality, while life course effect was found on the importance of community. In contrast to findings from other countries showing that young people attributed relatively high importance to leisure and relatively less importance to work, cohort effect regarding the latter was not observed in Israel. There, young people in the 1990s tended to view work and leisure as important as their predecessors did in the 1980s. Compared with research findings from the United States, Germany and Japan, work centrality in Israel was higher and more stable. (shrink)
We suggest to define objective probabilities by similarity-weighted empirical frequencies, where more similar cases get a higher weight in the computation of frequencies. This formula is justified intuitively and axiomatically, but raises the question, which similarity function should be used? We propose to estimate the similarity function from the data, and thus obtain objective probabilities. We compare this definition to others, and attempt to delineate the scope of situations in which objective probabilities can be used.
A decision maker has to choose one of several random variables whose distributions are not known. As a Bayesian, she behaves as if she knew the distributions. In this paper we suggest an axiomatic derivation of these (subjective) distributions, which is more economical than the derivations by de Finetti or Savage. Whereas the latter derive the whole joint distribution of all the available random variables, our approach derives only the marginal distributions. Correspondingly, the preference questionnaire needed in our case is (...) less smaller. (shrink)
The longitudinal research presented here is unique, having examined a model of stability and change in work values of the same people over the course of time. The purpose was to reflect the changes in work values that occurred in Israel during this period. The research focused on three domains: work goals, job satisfaction, and work centrality. Following an analysis of research literature, a model of work values was examined by the LISREL method. Instrumental and expressive goals effected work centrality (...) both directly and indirectly . While in 1981 only the positive effect of expressive goals on work centrality was significant, the 1993 analysis revealed that beyond the positive effect of expressive goals, there is also significant negative effect of instrumental goals on work centrality. Our research shows that the main changes occurred in peripheral values as compared with the stability of core values . Slight changes occurred in semi-peripheral values. (shrink)
New concepts may prove necessary to profit from the avalanche of sequence data on the genome, transcriptome, proteome and interactome and to relate this information to cell physiology. Here, we focus on the concept of large activity-based structures, or hyperstructures, in which a variety of types of molecules are brought together to perform a function. We review the evidence for the existence of hyperstructures responsible for the initiation of DNA replication, the sequestration of newly replicated origins of replication, cell division (...) and for metabolism. The processes responsible for hyperstructure formation include changes in enzyme affinities due to metabolite-induction, lipid-protein affinities, elevated local concentrations of proteins and their binding sites on DNA and RNA, and transertion. Experimental techniques exist that can be used to study hyperstructures and we review some of the ones less familiar to biologists. Finally, we speculate on how a variety of in silico approaches involving cellular automata and multi-agent systems could be combined to develop new concepts in the form of an Integrated cell (I-cell) which would undergo selection for growth and survival in a world of artificial microbiology. (shrink)