Description logics are a family of knowledge representation formalisms that are descended from semantic networks and frames via the system Kl-one. During the last decade, it has been shown that the important reasoning problems (like subsumption and satisfiability) in a great variety of description logics can be decided using tableau-like algorithms. This is not very surprising since description logics have turned out to be closely related to propositional modal logics and logics of programs (such as propositional dynamic logic), for which (...) tableau procedures have been quite successful.Nevertheless, due to different underlying institutions and applications, most description logics differ significantly from run-of-the-mill modal and program logics. Consequently, the research on tableau algorithms in description logics led to new techniques and results, which are, however, also of interest for modal logicians. In this article, we will focus on three features that play an important rôle in description logics (number restrictions, terminological axioms, and role constructors), and show how they can be taken into account by tableau algorithms. (shrink)

We describe BDD-based decision procedures for the modal logic K. Our approach is inspired by the automata-theoretic approach, but we avoid explicit automata construction. Instead, we compute certain fixpoints of a set of types — which can be viewed as an on-the-fly emptiness of the automaton. We use BDDs to represent and manipulate such type sets, and investigate different kinds of representations as well as a “level-based” representation scheme. The latter turns out to speed up construction and reduce memory consumption (...) considerably. We also study the effect of formula simplification on our decision procedures. To prove the viability of our approach, we compare our approach with a representative selection of other approaches, including a translation of K to QBF. Our results indicate that the BDD-based approach dominates for modally heavy formulae, while search-based approaches dominate for propositionally heavy formulae. (shrink)

This book examines the birth of the scientific understanding of motion. It investigates which logical tools and methodological principles had to be in place to give a consistent account of motion, and which mathematical notions were introduced to gain control over conceptual problems of motion. It shows how the idea of motion raised two fundamental problems in the 5th and 4th century BCE: bringing together being and non-being, and bringing together time and space. The first problem leads to the exclusion (...) of motion from the realm of rational investigation in Parmenides, the second to Zeno's paradoxes of motion. Methodological and logical developments reacting to these puzzles are shown to be present implicitly in the atomists, and explicitly in Plato who also employs mathematical structures to make motion intelligible. With Aristotle we finally see the first outline of the fundamental framework with which we conceptualise motion today. (shrink)

In this paper I investigate central temporal and spatial notions in the second part of Plato’s Parmenides and argue that also these notions, and not only the metaphysical ones usually discussed in the literature, can be understood as a response to positions and problems put on the table by Parmenides and Zeno. Of the spatial notions examined in the dialogue, I look at the problems raised for possessing location and shape, while with respect to temporal notions, I focus on the (...) discussion of ‘being in time’ and exaiphnês (the latter notion will be shown to be also an important influence for Aristotle’s Physics). In displaying a paradoxical character and taking up crucial notions from Parmenides, the second part of the Parmenides seems to display some resemblance to Zeno’s paradoxes. I will show, however, that in contrast to Zeno, the second part of Plato’s Parmenides also demonstrates Parmenides’ One to be problematic on its own terms. Furthermore, the dialogue presents not only important problems that these spatial and temporal notions seem to lead us into, but also establishes some positive features necessary to think of time and space. In this way, Plato’s Parmenides can be seen as contributing to the development of temporal and spatial conceptualisations in ancient Greek thought. (shrink)

(2013). Rational argument, rational inference. Argument & Computation: Vol. 4, Formal Models of Reasoning in Cognitive Psychology, pp. 21-35. doi: 10.1080/19462166.2012.689327.

This paper has two main goals: first, it reconstructs Aristotle’s account of measurement in his Metaphysics and shows how it connects to modern notions of measurement. Second, it demonstrates that Aristotle’s notion of measurement only works for simple measures, but leads him into a dilemma once it comes to measuring complex phenomena, like mo-tion, where two or more different aspects, such as time and space, have to be taken into account. This is shown with the help of Aristotle’s reaction to (...) one of the problems Zeno’s dichotomy paradox raises: Aristotle implicitly employs a complex measure of motion when solving this problem, while he explicitly characterizes the measure of motion as a simple measure in his Physics. (shrink)

This paper aims to show that—and how—Plato’s notion of the receptacle in the Timaeus provides the conditions for developing a mathematical as well as a physical space without itself being space. In response to the debate whether Plato’s receptacle is a conception of space or of matter, I suggest employing criteria from topology and the theory of metric spaces as the most basic ones available. I show that the receptacle fulfils its main task–allowing the elements qua images of the Forms (...) to exist as sensible things by being that in which the elements appear, change and move–in virtue of being pure continuity. All further qualifications required for a full notion of space are derived solely from the content of the receptacle. (shrink)

From the point of view of a dynamic morphology, form is not only the result of process(es) — it is process. This process may be analyzed in terms of two pairs of fundamental processes: growth and decay, differentiation and dedifferentiation. Each of these processes can be analyzed in terms of various modalities (parameters) and submodalities. This paper deals with those of growth (see Table 1). For the purpose of systematits and phylogenetic reconstruction the modalities and submodalities can be considered dynamic (...) characters that have states. Each state of such a dynamic character is a more detailed process, hence not static. For example, determinate growth represents a state of the dynamic character (or modality) of growth duration.The processes of Table 1 can be applied to the whole plant kingdom (although in certain cases only some processes of the whole set may be applicable). Thus, the diversity of plant form is seen as a diversity of process combinations. From this point of view, change in form implies change in the process combination(s). Questions that arise are, for example, the following: Which process combinations actually occur? Which of these are the most frequent? How and why have process combinations changed during ontogeny and phylogeny? (shrink)

A proposta deste artigo é proceder à análise de três obras utópicas escritas por mulheres, considerando os seus programas políticos em oposição às utopias masculinas canônicas, interpretando-as como feministas em seus projetos de abertura à cidadania feminina. Ao contar com a imaginação política como elemento imprescindível à escrita da utopia e ao opor-se à normatização da vida, Pizan, Cavendish e Gilman quebram o ciclo de engendramento distópico típico das utopias masculinistas normativas.

In recent years, the receipt and the perception of information has changed in ways which have fueled fears about the fates of our democracies. However, real information on these possibilities or the direction of these changes does not exist. Into this gap, Hahn and colleagues bring the power of Condorcet's (1785) Jury Theorem to show that changes in our information networks have affected voter inter‐dependence so that it is likely that voters are now collectively more ignorant even if individual voter (...) competence remains unchanged. (shrink)

Donald Davidson writes that “[r]easons for intending to do something are very much like reasons for action, indeed one might hold that they are exactly the same except for time.” That the reasons for forming an intention and the reasons for acting as intended are in some way related is a widely accepted claim. But it can take different forms: (1) the reasons may mirror each other so that there is a (derivative) reason to intend whenever there is a reason (...) to act; or (2) they may reduce to just one kind: perhaps all reasons for action are really reasons for forming intentions.3 Or the other way around: (3) all reasons for intentions are really reasons to act. The three versions are not equally strong contenders though. The third - that reasons to intend could reduce to reasons to act - seems unlikely. After all, there may be reasons to form future-directed intentions, in particular, independently of the reason to act as intended. The second suggestion falls prey to different considerations: reasons to act can, at least sometimes, be reasons to produce a certain outcome, quite independently of the intention with which the action is done, or whether it is done intentionally at all. In these cases, the reason to act is not (or not obviously) a reason to intend. Therefore, I don’t pursue the possibility of a reduction in this paper. My focus is on the first, non-reductive proposal. I will discuss various versions of it in some detail, but ultimately reject it. (shrink)

Background: Recent research has demonstrated that depressed individuals show impairments in inhibiting irrelevant emotional material, and that these impairments are linked to rumination. Cognitive inhibition, however, is not a unitary construct but consists of several components which operate at different stages of information processing. The present study was designed to assess two components of inhibition and examine their relation to depression and rumination in a sample of clinically depressed and healthy control participants. Methods: Twenty-two individuals diagnosed with a current depressive (...) episode and 27 never-disordered control participants completed an Emotional Flanker Task to assess individual differences in interference control and a modification of the Working Memory Selection Task to assess individual differences in the ability to discard no longer relevant emotional material from working memory. Participants completed self-report measures to assess depressive symptoms and rumination. Results: Clinically depressed compared to control participants showed significantly reduced interference control of irrelevant negative information. The groups, however, did not differ in their ability to discard no longer relevant negative information from working memory. In contrast, rumination was associated with difficulty removing no longer relevant negative material from working memory but not with deficits in interference control. Conclusions: Results highlight the importance of differentiating among components of inhibition to gain a better understanding of cognitive mechanisms underlying depression and rumination. (shrink)

This paper examines the basic question of how we can come to form accurate beliefs about the world when we do not fully know how good or bad our evidence is. Here, we show, using simulations with otherwise optimal agents, the cost of misjudging the quality of our evidence. We compare different strategies for correctly estimating that quality, such as outcome‐ and expectation‐based updating. We also identify conditions under which misjudgment of evidence quality can nevertheless lead to accurate beliefs, as (...) well as those conditions where no strategy will help. These results indicate both where people will nevertheless succeed and where they will fail when information quality is degraded. (shrink)

In this paper I show that one of the most fruitful ways of employing paradoxes has been as a philosophical method that forces us to reconsider basic assumptions. After a brief discussion of recent understandings of the notion of paradoxes, I show that Zeno of Elea was the inventor of paradoxes in this sense, against the background of Heraclitus’ and Parmenides’ way of argumentation: in contrast to Heraclitus, Zeno’s paradoxes do not ask us to embrace a paradoxical reality; and in (...) contrast to Parmenides, Zeno shows common assumptions to be internally problematic, not just in light of Eleatic positions. (shrink)

Possible measures to mitigate climate change require global collective actions whose impacts will be felt by many, if not all. Implementing such actions requires successful communication of the reasons for them, and hence the underlying climate science, to a degree that far exceeds typical scientific issues which do not require large-scale societal response. Empirical studies have identified factors, such as the perceived level of consensus in scientific opinion and the perceived reliability of scientists, that can limit people's trust in science (...) communicators and their subsequent acceptance of climate change claims. Little consideration has been given, however, to recent formal results within philosophy concerning the relationship between truth, the reliability of evidence sources, the coherence of multiple pieces of evidence/testimonies, and the impact of independence between sources of evidence. This study draws on these results to evaluate exactly what has been established in the empirical literature about the factors that bias the public's reception of scientific communications about climate change. (shrink)

In a notoriously obscure passage in Metaphysics 7.1 Aristotle claims that substance is primary in time. The only concrete literal interpretation suggested so far of this controversial claim is in terms of existing before and after in time. I argue that this interpretation faces serious problems. I then present a novel literal interpretation, in terms of being an appropriate subject of temporal predications, that is immune to these problems and strongly supported by philosophical and contextual considerations.

Our beliefs and opinions are shaped by others, making our social networks crucial in determining what we believe to be true. Sometimes this is for the good because our peers help us form a more accurate opinion. Sometimes it is for the worse because we are led astray. In this context, we address via agent-based computer simulations the extent to which patterns of connectivity within our social networks affect the likelihood that initially undecided agents in a network converge on a (...) true opinion following group deliberation. The model incorporates a fine-grained and realistic representation of belief and trust, and it allows agents to consult outside information sources. We study a wide range of network structures and provide a detailed statistical analysis concerning the exact contribution of various network metrics to collective competence. Our results highlight and explain the collective risks involved in an overly networked or partitioned society. Specifically, we find that 96% of the variation in collective competence across networks can be attributed to differences in amount of connectivity and clustering, which are negatively correlated with collective competence. A study of bandwagon or “group think” effects indicates that both connectivity and clustering increase the probability that the network, wholly or partly, locks into a false opinion. Our work is interestingly related to Gerhard Schurz’s work on meta-induction and can be seen as broadly addressing a practical limitation of his approach. (shrink)

This paper argues that the problem of how to act in the face of radical contingency is of central importance in Musil’s novel and intimately connected to what Musil calls the sense of possibility. There is a variety of different strategies by which individuals, and the state of Kakania as a whole, deal with contingency, and they all involve a claim to a kind of grounding or necessity; for example, the Parallel Campaign is one big attempt to ground Kakania in (...) what can be perceived as a form of metaphysical necessity. With the figure of Ulrich, Musil radicalizes the problem by showing the consequences of viewing even the relationship one has to one’s own self as contingent – the ultimate outcome of which is self-alienation. (shrink)

In this paper, I argue that a person can have a reason to do what she cannot do. In a nutshell, the argument is that a person can have derivate reasons relating to an action that she has a non-derivative reason to perform. There are clear examples of derivative reasons that a person has in cases where she cannot do what she (non-derivatively) has reason to do. She couldn’t have those derivative reasons, unless she also had the non-derivative reason to (...) do what she cannot do. I discuss a number of objections to this view, in particular two: (1) The objection that if there were reasons to do what one cannot do, many of those would be ‘crazy reasons’, and (2) the worry that if there were such reasons, then agents would have reasons to engage in futile deliberations and tryings. I develop an explanation of ‘crazy reasons’ that shows that not all reasons to do the impossible are crazy and only those that are need to be filtered out, and, regarding the second objecting, I show that the reasons for trying as well as for taking the means to doing something—instrumental reasons in a broad sense—are different from the reasons for performing the action in the first place. They are affected by impossibility, and we can explain why that is so. The view I argue for is that a person may have a reason to do what she cannot do, but she does not have a reason to try to do so or to take means to realizing the impossible. (shrink)

This paper argues that processes in the sensible realm can be in accord with reason in the Timaeus, since rationality is understood here as being based on regularity, which is conferred onto processes by time. Plato uses two different temporal structures in the Timaeus, associated with the contrast there drawn between Greek and Egyptian approaches to history. The linear order of before and after marks natural processes as rational and underlies the Greek treatment of history. By contrast, a bidirectional temporal (...) structure is the basis for the Egyptian approach to historical processes: present actions are not only determined by preceding ones in the past, but can also be influenced by the future (plans, aims). This latter temporal structure is shown to be necessary for learning from history, which makes human actions more regular. (shrink)

It is an assumption common to many theories of rationality that all practical reasons are based on a person's given desires. I shall call any approach to practical reasons which accepts this assumption a "Humean approach". In spite of many criticisms, the Humean approach has numerous followers who take it to be the natural and inevitable view of practical reason. I will develop an argument against the Humean view aiming to explain its appeal, as well as to expose its mistake. (...) I focus on just one argument in favour of the Humean approach, which I believe can be constructed as the background idea of many Humean accounts: the argument from motivation. (shrink)

The buck-passing account of values offers an explanation of the close relation of values and reasons for action: of why it is that the question whether something that is of value provides reasons is not ”open.” Being of value simply is, its defenders claim, a property that something has in virtue of its having other reason-providing properties. The generic idea of buck-passing is that the property of being good or being of value does not provide reasons. It is other properties (...) that do. There are, however, at least three versions of the account which differ in their understanding of those “other properties.” The first two versions both assume that non-normative properties provide reasons, the difference being that the second allows that normative properties also provide reasons. Both run into difficulties, which I explain, in trying to defend the claim that non-normative properties provide reasons for action. The third version of the buck-passing account which explains being of value in terms of more specific evaluative properties that are reason-providing remains unpersuasive as well. Once we understand the relation between general and specific properties as a difference in degree, there is no space for a reduction of the one kind of properties to the other. In section II I sketch an alternative account of the relation between reasons and values, which is based on a thesis that I call the Conceptual Link and the claim that values are not just co-extensive with reasons, but explain them. (shrink)

This paper investigates the dynamic and performative construction of publics in public engagement exercises. In this investigation, we, on the one hand, analyse how public engagement settings as political machineries frame particular kinds of roles and identities for the participating publics in relation to ‘the public at large’. On the other hand, we study how the participating citizens appropriate, resist and transform these roles and identities, and how they construct themselves and the participating group in relation to wider publics. The (...) empirical basis of our argument is a discussion of four different kinds of participation events in Austria. Building on these observations we develop conclusions about the public up-take of public participation in technoscience and the role of public engagement in current techno-political cultures. (shrink)

Bei Kant tauchen viele antike Autoren und Theorien auf. In dieser ersten Gesamtbearbeitung zum Thema wird gegen eine langjährige Forschungsmeinung gezeigt, dass nicht so sehr Platon und Aristoteles als vielmehr der hellenistischen Philosophie die entscheidende Rolle für sein Denken zukommt. Anhand der drei Kritiken werden Konstanzen und Umbrüche seines Antikeverständnisses herausgearbeitet und in ihren Konsequenzen für die Kantdeutung beleuchtet.

Luck, Value, and Commitment comprises eleven new essays which engage with, or take their point of departure from, the influential work in moral and political philosophy of Bernard Williams (1929-2003).

Is the wrongness of an action a reason not to perform it? Of course it is, you may answer. That an action is wrong both explains and justifies not doing it. Yet, there are doubts. Thinking that wrongness is a reason is confused, so an argument by Jonathan Dancy. There can’t be such a reason if ‘ϕ-ing is wrong’ is verdictive, and an all things considered judgment about what (not) to do in a certain situation. Such judgments are based on (...) all the relevant reasons for and against ϕ-ing. If that ϕ-ing is wrong, while being an all things considered verdict, would itself be a reason, it would upset the balance of reasons: it would be a further reason which has not yet been considered in reaching the verdict. Hence, the judgment wasn’t ‘all things considered' after all. I show that the argument against wrongness being a reason is unsuccessful, because its main assumption is false. Is main assumption is that a consideration which necessarily does not affect the balance of reasons is not a reason. I also argue that there can be no deontic buck-passing account. (shrink)

During mammalian development, maintenance of cell fate through mitotic divisions require faithful replication not only of the DNA but also of a particular epigenetic state. Germline cells have the capacity of erasing this epigenetic memory at crucial times during development, thereby resetting their epigenome. Certain marks, however, appear to escape this reprogramming, which allows their transmission to the offspring and potentially guarantees transgenerational epigenetic inheritance. Here we discuss the molecular requirements for faithful transmission of epigenetic information and our current knowledge (...) about the transmission of epigenetic information through generations. (shrink)