To qualify the truth of a proposition probabilistically is to place it within the scope of a special type of alethic modality. We expect that, as in other modal contexts, the merely probabilistic truth of an assumption in a valid inference must carry over to whatever conclusions are derived from the assumption. That expectation, however, is not always fulfilled in ordinary reasoning about conditional probabilities. There are simpler ways of illustrating what I shall call the paradoxes of conditional probabilistic reasoning (...) in ordinary language, but the following argument is a colorful example. Consider an apparently deductively valid inference, by an imaginary inmate of a penal institution supervised by a bitterly hated warden who is surrounded by dangerous criminals, including the argument’s author. (shrink)

According to the so-called ‘Taking Condition’ (a label due to Boghossian 2014) on inference, for a response R in circumstances C to count as an instance of reasoning or inferring, it must be the case that the agent’s taking it that R is warranted or justified in C plays (the right sort of) explanatory role in her R-ing. The Taking Condition has come under much criticism in the theory of reasoning. While I believe that these criticisms can be answered, my (...) aim in this paper is to build a positive case for the Taking Condition. More specifically, I argue that views based on the Taking Condition do a much better job accounting for crucial features of reasoning—especially once we recognize the pervasiveness and significance of defeasibility in our reasoning. (shrink)

A number of single- and dual-process theories provide competing explanations as to how reasoners evaluate conditional arguments. Some of these theories are typically linked to different instructions—namely deductive and inductive instructions. To assess whether responses under both instructions can be explained by a single process, or if they reflect two modes of conditional reasoning, we re-analysed four experiments that used both deductive and inductive instructions for conditional inference tasks. Our re-analysis provided evidence consistent with a single process. In two new (...) experiments we established a double dissociation of deductive and inductive instructions when validity and plausibility of conditional problems were pitted against each other. This indicates that at least two processes contribute to conditional reasoning. We conclude that single-process theories of conditional reasoning cannot explain the observed results. Theories that postulate at least two processes are needed to account for our findings. (shrink)

This article investigates the possibility and potential of a critical theory of nature and technology. A blind acceptance of the uninhibited development of the forces of production led traditional critical theory to neglect these areas, which it assigned to the domain of the natural sciences. The recognition that nature is socially constituted compels a reformulation of the interest in reasonable conditions that guided the older critical theory. The article asks what criteria offer themselves for determining what would be reasonable in (...) our relations both to the nature that we ourselves are, the body, as well as to the nature that we ourselves are not. Such questions might revitalize critical theory in the very moment it threatens to become historically obsolete. (shrink)

This article investigates the possibility and potential of a critical theory of nature and technology. A blind acceptance of the uninhibited development of the forces of production led traditional critical theory to neglect these areas, which it assigned to the domain of the natural sciences. The recognition that nature is socially constituted compels a reformulation of the interest in reasonable conditions that guided the older critical theory. The article asks what criteria offer themselves for determining what would be reasonable in (...) our relations both to the nature that we ourselves are, the body, as well as to the nature that we ourselves are not. Such questions might revitalize critical theory in the very moment it threatens to become historically obsolete. (shrink)

We present two approaches to investigate the validity of connexive principles and related formulas and properties within coherence-based probability logic. Connexive logic emerged from the intuition that conditionals of the form if not-A, thenA, should not hold, since the conditional’s antecedent not-A contradicts its consequent A. Our approaches cover this intuition by observing that the only coherent probability assessment on the conditional event $${A| \overline{A}}$$ A | A ¯ is $${p(A| \overline{A})=0}$$ p ( A | A ¯ ) = (...) 0. In the first approach we investigate connexive principles within coherence-based probabilistic default reasoning, by interpreting defaults and negated defaults in terms of suitable probabilistic constraints on conditional events. In the second approach we study connexivity within the coherence framework of compound conditionals, by interpreting connexive principles in terms of suitable conditional random quantities. After developing notions of validity in each approach, we analyze the following connexive principles: Aristotle’s theses, Aristotle’s Second Thesis, Abelard’s First Principle, and Boethius’ theses. We also deepen and generalize some principles and investigate further properties related to connexive logic (like non-symmetry). Both approaches satisfy minimal requirements for a connexive logic. Finally, we compare both approaches conceptually. (shrink)

There is a long tradition in formal epistemology and in the psychology of reasoning to investigate indicative conditionals. In psychology, the propositional calculus was taken for granted to be the normative standard of reference. Experimental tasks, evaluation of the participants’ responses and psychological model building, were inspired by the semantics of the material conditional. Recent empirical work on indicative conditionals focuses on uncertainty. Consequently, the normative standard of reference has changed. I argue why neither logic nor standard probability (...) theory provide appropriate rationality norms for uncertain conditionals. I advocate coherence based probability logic as an appropriate framework for investigating uncertain conditionals. Detailed proofs of the probabilistic non-informativeness of a paradox of the material conditional illustrate the approach from a formal point of view. I survey selected data on human reasoning about uncertain conditionals which additionally support the plausibility of the approach from an empirical point of view. (shrink)

This paper reviews the psychological investigation of reasoning with conditionals, putting an emphasis on recent work. In the first part, a few methodological remarks are presented. In the second part, the main theories of deductive reasoning (mental rules, mental models, and the probabilistic approach) are considered in turn; their content is summarised and the semantics they assume for if and the way they explain formal conditional reasoning are discussed, in particular in the light of experimental work on the probability (...) of conditionals. The last part presents the recent shift of interest towards the study of conditional reasoning in context, that is, with large knowledge bases and uncertain premises. (shrink)

Abstract David Sobel (2001) objects to Bernard Williams's internalism, the view that an agent has a reason to perform an action only if she has some motive that will be served by performing that action. Sobel is an unusual challenger in that he endorses neo-Humean subjectivism, ?the view that it is the agent's subjective motivational set that makes it the case that an agent does or does not have a reason to φ? (219). Sobel's objection in fact arises from this (...) very commitment. Internalism, he says, is incompatible with the best subjectivist accounts of reasons for action?accounts that suggest that there are what he calls fragile reasons and perhaps also superfragile ones, both of which allegedly provide for counterexamples to internalism. I argue that such reasons do not in fact threaten internalism. I then briefly explore whether internalism is vulnerable to a related charge?that it commits the conditional fallacy. (shrink)

The reasoning abilities of large language models (LLMs) are the topic of a growing body of research in artificial intelligence and cognitive science. In this paper, we probe the extent to which a dozen LLMs are able to distinguish logically correct inferences from logically fallacious ones. We focus on inference patterns involving conditionals (e.g., 'If Ann has a queen, then Bob has a jack') and epistemic modals (e.g., 'Ann might have an ace', 'Bob must have a king'). These inference (...) patterns have been of special interest to logicians, philosophers, and linguists, since they plausibly play a central role in human reasoning. Assessing LLMs on these inference patterns is thus highly relevant to the question of how much the reasoning abilities of LLMs match those of humans. Among the LLMs we tested, all but GPT-4 often make basic mistakes with conditionals. Moreover, even GPT-4 displays logically inconsistent judgments across inference patterns involving epistemic modals. (shrink)

Children approach counterfactual questions about stories with a reasoning strategy that falls short of adults’ Counterfactual Reasoning (CFR). It was dubbed “Basic Conditional Reasoning” (BCR) in Rafetseder et al. (Child Dev 81(1):376–389, 2010). In this paper we provide a characterisation of the differences between BCR and CFR using a distinction between permanent and nonpermanent features of stories and Lewis/Stalnaker counterfactual logic. The critical difference pertains to how consistency between a story and a conditional antecedent incompatible with a nonpermanent feature of (...) the story is achieved. Basic conditional reasoners simply drop all nonpermanent features of the story. Counterfactual reasoners preserve as much of the story as possible while accommodating the antecedent. (shrink)

This paper sketches a theory of the reason‐giving force of well‐being that allows us to reconcile our intuitions about two of the most recalcitrant problem cases in population ethics: Jan Narveson's Procreation Asymmetry and Derek Parfit's Non‐Identity Problem. I show that what has prevented philosophers from developing a theory that gives a satisfactory account of both these problems is their tacit commitment to a teleological conception of well‐being, as something to be ‘promoted’. Replacing this picture with one according to which (...) our reasons to confer well‐being on people are conditional on their existence allows me to do better. It also enables us to understand some of the deep structural parallels between seemingly disparate normative phenomena such as procreating and promising. The resulting theory charts a middle way between the familiar dichotomy of narrow person‐affecting theories and totalist or wide‐person affecting theories in population ethics. (shrink)

Probabilistic theories of reasoning assume that people use their prior knowledge to estimate the conditional probability of q given p and that this probability predicts the acceptance of modus ponens inferences. But how do people reason with unfamiliar conditionals for which they do not have prior knowledge? Reasoning without prior knowledge has been extensively investigated in experiments in which participants were instructed to reason deductively. But it is still not clear how people reason with unfamiliar conditionals when they (...) are instructed to reason as in daily life. Can probabilities also predict reasoning with unfamiliar content? In two experiments we instructed participants to reason as in everyday life and to evaluate conclusions from familiar and unfamiliar conditionals. Results showed that reasoning with familiar conditionals can be predicted by the conditional probability. For unfamiliar conditionals, however, this was not the case. Conclusions from unfamiliar conditionals were accepted more strongly than what could be expected according to their conditional probability. Our findings challenge probabilistic theories of reasoning and suggest that other approaches, such as a dual-strategy model, describe our results more adequately. (shrink)

Case-based reasoning is a familiar method of evaluating sentences. But when applied to conditionals, it seems to lead to implausible conclusions. In this paper I argue that the problem arises from equating the probability of a conditional sentence on the evidential supposition of some condition with the conditional probability of the former, given the latter.

Most of the core concepts of the Western philosophical tradition originate in antiquity. Yet boredom is strikingly absent from classical thought. In this philosophical study, Dmitri Nikulin explores the concept's genealogy to argue that boredom is the mark of modernity. Nikulin contends that boredom is a specifically modern phenomenon. He provides a critical reconstruction of the concept of the modern subject as universal, rational, autonomous, and self-sufficient. Understanding itself in this way, this subject is at once the protagonist, playwright, director, (...) and spectator of the staged drama of human existence. It is therefore inevitably monological, lonely, and alone, and can neither escape its own presence nor get rid of it. In other words, it is bored-and this boredom is the fundamental expression and symptom of the modern condition. Considering such thinkers as Descartes, Pascal, Kant, Kierkegaard, Kracauer, Heidegger, and Benjamin, Critique of Bored Reason places boredom on center stage in the philosophical critique of modernity. Nikulin also considers the alternative to the notion of the autonomous subject in the-nonbored and nonboring-dialogic and comic subject capable of shared existence with others. (shrink)

An experiment was conducted to investigate the relative contributions of syntactic form and content to conditional reasoning. The content domain chosen was that of causation. Conditional statements that described causal relationships (if (cause>, then (effect>) were embedded in simple arguments whose entailments are governed by the rules -oftruth-functional logic (i.e., modus ponens, modus tollens, denying the antecedent, and affirming the consequent). The causal statements differed in terms ofthe number of alternative causes and disabling conditions that characterized the causal relationship. (A (...) disabling condition is an event that prevents an effect from occurring even though a relevant cause is present.) Subjects were required to judge whether or not each argument’s conclusion could be accepted. Judgments were found to vary systematically with the number of alternative causes and disabling conditions. Conclusions of arguments based on conditionals with few alternative causes or disabling conditionswerefoun~d:tobe-rnore accept~ able than cdnclusions based on those with many. (shrink)

Many metaethicists endorse a cognitive constraint which links the reasons for which we act or hold attitudes (motivating reasons) to normative reasons (reasons that speak in favour of an action or attitude). As traditionally formulated, this constraint (known as the Taking Condition) requires that an agent’s motivating reasons are mentally represented by her as corresponding normative reasons. In response to the charge that the Taking Condition is overly demanding, Errol Lord and Kurt Sylvan have (...) proposed a reformulation which eschews the need for normative representation (Lord and Sylvan 2019 [“Prime Time (for the Basing Relation).” In Well-Founded Belief, edited by J. Adam Carter, and Patrick Bondy, 141–173. London and New York: Routledge]). As they argue, agents must treat their motivating reasons as normative reasons, where this notion picks out a specific set of dispositions rather than a representational state. I argue that this proposal seriously distorts our understanding of the relation between an action or attitude and the reasons for which we perform or hold it. On the plausible assumption that an account of motivating reasons should not stray too far from this understanding, this response to the over-demandingness charge thus fails. I also provide some directions on how friends of the Taking Condition should instead respond this charge. (shrink)

We present a unified approach for investigating rational reasoning about basic argument forms involving indicative conditionals, counterfactuals, and basic quantified statements within coherence-based probability logic. After introducing the rationality framework, we present an interactive view on the relation between normative and empirical work. Then, we report a new experiment which shows that people interpret indicative conditionals and counterfactuals by coherent conditional probability assertions and negate conditionals by negating their consequents. The data support the conditional probability interpretation of (...) conditionals and the narrow-scope reading of the negation of conditionals. Finally, we argue that coherent conditional probabilities are important for probabilistic analyses of conditionals, nonmonotonic reasoning, quantified statements, and paradoxes. (shrink)

This paper addresses the apparent mismatch between the normative and descriptive literatures in the cognitive science of conditional reasoning. Descriptive psychological theories still regard material implication as the normative theory of the conditional. However, over the last 20 years in the philosophy of language and logic the idea that material implication can account for everyday indicative conditionals has been subject to severe criticism. The majority view is now apparently in favour of a subjective conditional probability interpretation. A comparative model (...) fitting exercise is presented that shows that a conditional probability model can explain as much of the data on abstract indicative conditional reasoning tasks as psychological theories that supplement material implication with various rationally unjustified processing assumptions. Consequently, when people are asked to solve laboratory reasoning tasks, they can be seen as simply generalising their everyday probabilistic reasoning strategies to this novel context. (shrink)

This book covers lymphoproliferative disorders in patients with congenital or acquired immunodeficiencies. Acquired immunodeficiencies are caused by infections with the human immunodeficiency virus or arise following immunosuppressive therapy administered after organ transplantation or to treat connective tissue diseases such as rheumatoid arthritis. It was recently discovered that various diseases or therapeutic modalities that induce a state of immunosuppression may cause virally driven lymphoproliferations. This book summarizes for the first time this group of immunodeficiency-associated lymphoproliferations.

We report two new phenomena of deontic reasoning: (1) For conditionals with deontic content such as, "If the nurse cleaned up the blood then she must have worn rubber gloves", reasoners make more modus tollens inferences (from "she did not wear rubber gloves" to "she did not clean up the blood") compared to conditionals with epistemic content. (2) For conditionals in the subjunctive mood with deontic content, such as, "If the nurse had cleaned up the blood then (...) she must have had to wear rubber gloves", reasoners make the same frequency of all inferences as they do for conditionals in the indicative mood with deontic content. In this regard, subjunctive deontics are different from subjunctive epistemic conditionals: reasoners interpret subjunctive epistemic conditionals as counterfactual and they make more negative inferences such as modus tollens from them. The experiments show these two phenomena occur for deontic conditionals that contain the modal auxiliary "must" and ones that do not. We discuss the results in terms of the mental representations of deontic conditionals and of counterfactual conditionals. (shrink)

In this article we introduce a logical structure for normative reasoning, called Normative Detachment Structure with Ideal Conditions, that can be used to represent the content of certain legal texts in a normalized way. The structure exploits the deductive properties of a system of bimodal logic able to distinguish between ideal and actual normative statements, as well as a novel formalization of conditional normative statements able to capture interesting cases of contrary-to-duty reasoning and to avoid deontic paradoxes. Furthermore, we illustrate (...) how the theoretical framework proposed can be mechanized to get an automated procedure of query-answering on an example of legal text. (shrink)

Four experiments are reported which investigated the types of truth tables that people associate with conditional sentences and the kinds of inferences that they will draw from them. The present studies differed from most previous ones in using different types of content in the conditionals, for example promises and warnings. It was found that the type of content had a strong and consistent effect on both truth tables and inferences. It is suggested that this is because in real life (...) conditionals make probabilistic assertions, and that the strength of the probabilistic link is determined by the situation in which the conditional occurs. The implications of these findings for current theories of reasoning are considered and it is concluded that none of them is entirely satisfactory. It is suggested that more linguistically based theories may prove more successful. (shrink)

Theoretical reasoning (inference) is a conscious personal‐level activity and a causal process. It is the process of revising one's beliefs for a reason whereby some of our beliefs cause or result in other beliefs. But inference is more than mere causation. This raises the question of what exactly distinguishes theoretical reasoning from mere causal processes. Paul Boghossian has located the distinguishing feature of inference in, what he calls, the “taking condition” requirement (TC). It turns out, however, that all attempts to (...) explain this notion fail. In this paper, I shall offer an indirect argument for the taking condition grounded in a specific account of the structure of epistemic reasons that distinguishes two levels of epistemic normativity, namely, the possession and justification levels. I show how such an account can legitimize the role of (TC) in reasoning and deflect the standard objections raised against it. Finally, I explain how this proposal naturally accommodates the defeasibility of reasoning. (shrink)

Political philosophers have long focused on how to explain democratically legitimate governance under social conditions of pluralism. The challenge, when framed this way, is how to justify a common set of political principles without imposing controversial moral, religious, or metaphysical doctrines on one another. In this paper I propose an alternate starting point, replacing the concept of “social conditions of pluralism” with the background assumption that democratic societies must respond to “social conditions of strangerhood.” In the first section, I make (...) my case for viewing political relationships in terms of relationships with and as strangers, partly illustrated by empirical examples. In the second section, I explain why I think solutions to the challenges of democratic pluralism in terms of the support for public deliberation and reasoning are doomed to fail in addressing much deeper dilemmas posed by the persistence of governing as strangers to the extent that they depend on ties of cultural or epistemic familiarity and commonality. Finally, in the third section, I propose ways we might change our expectations of democratic legitimacy to better facilitate our political relationships with and as strangers. (shrink)

This paper addresses the apparent mismatch between the normative and descriptive literatures in the cognitive science of conditional reasoning. Descriptive psychological theories still regard material implication as the normative theory of the conditional. However, over the last 20 years in the philosophy of language and logic the idea that material implication can account for everyday indicative conditionals has been subject to severe criticism. The majority view is now apparently in favour of a subjective conditional probability interpretation. A comparative model (...) fitting exercise is presented that shows that a conditional probability model can explain as much of the data on abstract indicative conditional reasoning tasks as psychological theories that supplement material implication with various rationally unjustified processing assumptions. Consequently, when people are asked to solve laboratory reasoning tasks, they can be seen as simply generalising their everyday probabilistic reasoning strategies to this novel context. (shrink)

This book reviews the work of prominent psychologists and philosophers on conditional reasoning. It provides empirical research on how people deal with conditional arguments and examines how conditional statements are used and interpreted in everyday communication.

The paper presents a non-monotonic inference relation on a language containing a conditional that satisfies the Ramsey Test. The logic is a weakening of classical logic and preserves many of the ‘paradoxes of implication’ associated with the material implication. It is argued, however, that once one makes the proper distinction between supposing that something is the case and accepting that it is the case, these ‘paradoxes’ cease to be counterintuitive. A representation theorem is provided where conditionals are given a (...) non-bivalent semantics and epistemic states are represented via preferential models. (shrink)

This study examined the hypothesis that a key process in conditional reasoning with concrete premises involves on-line retrieval of information about potential alternate antecedents. Participants were asked to solve reasoning problems with causal conditional premises (If cause P then effect Q). These premises were inserted into short contexts. The availability of potential alternatives was varied from one context to another by adding statements that explicitly invalidated one or more of these alternatives (i.e., other causes that lead to the effect Q). (...) The invalidated alternatives differed in the degree of their semantic association to the consequent term (Q). The results show that the effect of invalidating one or more potential alternatives on the two uncertain logical forms, AC and DA, was largely determined by their relative associative strength. These results strongly support a model for conditional reasoning with causal premises that supposes that a key element in responding to the uncertain logical forms is on-line retrieval of at least one potential alternative antecedent. (shrink)

This article is about conditionalized modal statements whose antecedents concern a preferential attitude of an agent. The focus is on anankastic conditionals or, as they are known in the philosophical literature, hypothetical imperatives. We present a linguistically-motivated analysis of anankastic and related conditionals and use it to address challenges for semantic theories of natural language conditionals motivated by certain philosophical concerns about practical reasoning and the requirements of rationality.

We report three experimental studies of reasoning with double conditionals, i.e. problems based on premises of the form: If A then B. If B then C. where A, B, and C, describe everyday events. We manipulated both the logical structure of the problems, using all four possible arrangements (or “figures” of their constituents, A, B, and C, and the believability of the two salient conditional conclusions that might follow from them, i.e. If A then C, or If C then (...) A. The experiments showed that with figures for which there was a valid conclusion, the participants more often, and more rapidly, drew the valid conclusion when it was believable than when it was unbelievable. With figures for which there were no valid conclusions, the participants tended to draw whichever of the two conclusions was believable. These results were predicted by the theory that reasoning depends on constructing mental models of the premises. (shrink)

The main aim of this paper is to study the notion of conditional right by means of a dialogical approach to constructive type theory (CTT). We will develop this idea in a framework where the distinction between local-reason and strategic-reason leads to the further distinction between two basic kinds of pieces of evidence, factual and logical. The present paper is based on Rahman (2015). However, though the underlying CTT-analysis is the same, the dialogical reconstruction makes use of a new way (...) of linking dialogical logic and CTT. (shrink)

In the first part of this paper, I delineate Peirce's general concept of diagrammatic reasoning from other usages of the term that focus either on diagrammatic systems as developed in logic and AI or on reasoning with mental models. The main function of Peirce's form of diagrammatic reasoning is to facilitate individual or social thinking processes in situations that are too complex to be coped with exclusively by internal cognitive means. I provide a diagrammatic definition of diagrammatic reasoning that emphasizes (...) the construction of, and experimentation with, external representations based on the rules and conventions of a chosen representation system. The second part starts with a summary of empirical research regarding cognitive effects of working with diagrams and a critique of approaches that use “mental models” to explain those effects. The main focus of this section is, however, to elaborate the idea that diagrammatic reasoning should be conceptualized as a case of “distributed cognition.” Using the mathematics lesson described by Plato in his Meno, I analyze those cognitive conditions of diagrammatic reasoning that are relevant in this case. (shrink)

Conditionals are most important objects in knowledge representation, commonsense reasoning and belief revision. Due to their non-classical nature, however, they are not easily dealt with. This paper presents a new approach to conditionals, which is apt to capture their dynamic power particularly well. We show how this approach can be applied to represent conditional knowledge inductively, and to guide revisions of epistemic states by sets of beliefs. In particular, we generalize system-Z* as an appropriate counterpart to maximum entropy-representations (...) in a semi-quantitative setting, and provide a theoretical justification to make its basic ideas usable also for belief revision. (shrink)

ABSTRACTStudies examining the interpretation that is given to if–then statementstypically use what are referred to as basic conditionals, which give contextless relations between two unrelated concrete terms. However, there is some evidence that basic conditionals require a more abstract form of representation. In order to examine this, we presented participants with truth-table tasks involving either basic conditionals or conditionals referring to imaginary categories, and standard conditional inference tasks with abstract and familiar premises. As expected, fewer typical (...) defective conditional interpretations were given to basic conditionals. In addition, partial correlations showed a unique relationship between the interpretation of basic conditionals and abstract inferential reasoning. Results suggest that people process basic conditionals as a form of abstract reasoning, and that the interpretation of conditionals... (shrink)

Argumentation can play an important role in medical consultation. A doctor could, for instance, argue in support of a treatment advice to overcome a patient’s hesitance about it. In this argumentation, the doctor might explicitly present him- or herself as an authority, thereby presenting an argument by authority. Depending on the specific conditions under which the doctor advances such an argument, the doctor’s argument by authority can constitute a sound or a fallacious contribution to the discussion. In this paper, I (...) shall determine what the specific soundness conditions are that apply to a doctor’s argumentation by authority in medical consultation. Keywords: medical consultation, pragma-dialectical analysis, soundness condition, argument by authority, doctor-patient communication. (shrink)

We report three experimental studies of reasoning with double conditionals, i.e. problems based on premises of the form: If A then B. If B then C. where A, B, and C, describe everyday events. We manipulated both the logical structure of the problems, using all four possible arrangements (or ''figures" of their constituents, A, B, and C, and the believability of the two salient conditional conclusions that might follow from them, i.e. If A then C , or If C (...) then A . The experiments showed that with figures for which there was a valid conclusion, the participants more often, and more rapidly, drew the valid conclusion when it was believable than when it was unbelievable. With figures for which there were no valid conclusions, the participants tended to draw whichever of the two conclusions was believable. These results were predicted by the theory that reasoning depends on constructing mental models of the premises. (shrink)

Nonmonotonic reasoning is a discipline of computer science, epistemology, and cognition: It models inferences where classical logic is inadequate in symbolic AI, defines normative models for reasoning with defeasible information in epistemology, and models human reasoning under information change in cognition. Its building blocks are defeasible rules formalised as DeFinetti conditionals. In this thesis, Christian Eichhorn examines qualitative and semi-quantitative inference relations on top said conditionals, using the conditional structure of the knowledge base and Spohn’s Ordinal Conditional Functions, (...) using established properties. Converting network approaches from probabilistics, he shows how to approach the relations with regard to implementation. (shrink)

The main aim of this paper is to study the notion of conditional right by means of constructive type theory (CTT) which provides the means to develop a system of contentual inferences rather than of syntactic derivations. Moreover, in line with Armgardt, we will first study the general notion of dependence as triggered by hypotheticals and then the logical structure of dependence specific to conditional right. I will develop this idea in a dialogical framework where the distinction between play-object and (...) strategy-object leads to the further distinction between two basic kinds of pieces of evidence and where meanings is constituted by the interaction of obligations and entitlements. The present paper is based on Rahman (2015). However, though the underlying CTT-analysis is the same, the dialogical reconstruction makes use of a new way of linking dialogical logic and CTT. Introduction. (shrink)

Ranking theory is a formal epistemology that has been developed in over 600 pages in Spohn's recent book The Laws of Belief, which aims to provide a normative account of the dynamics of beliefs that presents an alternative to current probabilistic approaches. It has long been received in the AI community, but it has not yet found application in experimental psychology. The purpose of this paper is to derive clear, quantitative predictions by exploiting a parallel between ranking theory and a (...) statistical model called logistic regression. This approach is illustrated by the development of a model for the conditional inference task using Spohn's ranking theoretic approach to conditionals. (shrink)

We report two studies on the effect of implicitly versus explicitly conveying affirmation and denial problems about conditionals. Recently Evans and Handley (1999) and Schroyens et al. (1999b, 2000b) showed that implicit referencing elicits matching bias: Fewer determinate inferences are made, when the categorical premise (e.g., B) mismatches the conditional's referred clause (e.g., A). Also, the effect of implicit affirmation (B affirms not-A) is larger than the effect of implicit denial (B denies A). Schroyens et al. hypothesised that this (...) interaction is due to uncertainty in the case-wise affirmation of the contrast class of negated elements involved in implicit affirmations. In Experiment 1 we tested this hypothesis by manipulating the set size of the conditional clauses. The results confirm that binary sets, where the contrast class is a singleton, eliminate the differential effect of implicit affirmation and denial. With non-binary sets the interaction is not modulated by the scope of the contrast class (3, 5, 9 elements). Experiment 2 further investigated the role of contrast classes by using class inclusion to construct implicit affirmations (Mammal vs Mammal or Monkey) and implicit denial (No-Mammal vs Mammal or Monkey), in addition to the standard implicit problems mediated by contrast-class inclusion [(No-)Mammal/No-Mammal; Reptile; Snake). Findings indicate that class inclusion (Mammal/Monkey; Reptile/ Snake) only marginally affects performance, and is independent of the type of problem. This would suggest that the implicitness problem-type interaction is dependent on constructing contrast classes. However, the experiment failed to replicate the interaction, even on the subset of problems repeating the abstract letter/number format of Experiment 1. Moreover, with the natural binary set-sizes (vowels/consonants) the implicitness effect was eliminated entirely. (shrink)