Page 1. Economics and Philosophy, 26 291--320 Copyright C Cambridge University Press doi: 10.1017 / S0266267110000386 TWO KINDS OF WE-REASONING RAUL HAKLI, KAARLO MILLER AND RAIMO TUOMELA University of Helsinki.

Various sources in the literature claim that the deduction theorem does not hold for normal modal or epistemic logic, whereas others present versions of the deduction theorem for several normal modal systems. It is shown here that the apparent problem arises from an objectionable notion of derivability from assumptions in an axiomatic system. When a traditional Hilbert-type system of axiomatic logic is generalized into a system for derivations from assumptions, the necessitation rule has to be modified in a way that (...) restricts its use to cases in which the premiss does not depend on assumptions. This restriction is entirely analogous to the restriction of the rule of universal generalization of first-order logic. A necessitation rule with this restriction permits a proof of the deduction theorem in its usual formulation. Other suggestions presented in the literature to deal with the problem are reviewed, and the present solution is argued to be preferable to the other alternatives. A contraction-and cut-free sequent calculus equivalent to the Hubert system for basic modal logic shows the standard failure argument untenable by proving the underivability of DA from A. (shrink)

A proof-theoretical treatment of collectively accepted group beliefs is presented through a multi-agent sequent system for an axiomatization of the logic of acceptance. The system is based on a labelled sequent calculus for propositional multi-agent epistemic logic with labels that correspond to possible worlds and a notation for internalized accessibility relations between worlds. The system is contraction- and cut-free. Extensions of the basic system are considered, in particular with rules that allow the possibility of operative members or legislators. Completeness with (...) respect to the underlying Kripke semantics follows from a general direct and uniform argument for labelled sequent calculi extended with mathematical rules for frame properties. As an example of the use of the calculus we present an analysis of the discursive dilemma. (shrink)

Endorsing the idea of group knowledge seems to entail the possibility of group belief as well, because it is usually held that knowledge entails belief. It is here studied whether it would be possible to grant that groups can have knowledge without being committed to the controversial view that groups can have beliefs. The answer is positive on the assumption that knowledge can be based on acceptance as well as belief. The distinction between belief and acceptance can be seen as (...) a refinement of the ordinary language concept of belief, and it may be useful in understanding the nature of epistemic justification and classifying various types of epistemic subjects. (shrink)

Epistemic justification of non-summative group beliefs is studied in this paper. Such group beliefs are understood to be voluntary acceptances, the justification of which differs from that of involuntary beliefs. It is argued that whereas epistemic evaluation of involuntary beliefs can be seen not to require reasons, justification of voluntary acceptance of a proposition as true requires that the agent, a group or an individual, can provide reasons for the accepted view. This basic idea is studied in relation to theories (...) of dialectical justification in which justification is taken to require ability to justify. Since the reasons offered can in principle always be challenged, there is no ultimate end to the dialectical chain of justification. This makes justification of acceptance, and thus group belief, social and, in a way, contextual, but this does not seem to entail strong forms of epistemic relativism. (shrink)

Attitudes toward robots influence the tendency to accept or reject robotic devices. Thus it is important to investigate whether and how attitudes toward robots can change. In this pilot study we investigate attitudinal changes in elderly citizens toward a tele-operated robot in relation to three parameters: (i) the information provided about robot functionality, (ii) the number of encounters, (iii) personality type. Fourteen elderly residents at a rehabilitation center participated. Pre-encounter attitudes toward robots, anthropomorphic thinking, and personality were assessed. Thereafter the (...) participants interacted with a tele-operated robot (Telenoid) during their lunch (c. 30 min.) for up to 3 days. Half of the participants were informed that the robot was tele-operated (IC) whilst the other half were naïve to its functioning (UC). Post-encounter assessments of attitudes toward robots and anthropomorphic thinking were undertaken to assess change. Attitudes toward robots were assessed with a new generic 35-items questionnaire (attitudes toward social robots scale: ASOR-5), offering a differentiated conceptualization of the conditions for social interaction. There was no significant difference between the IC and UC groups in attitude change toward robots though trends were observed. Personality was correlated with some tendencies for attitude changes; Extraversion correlated with positive attitude changes to intimate-personal relatedness with the robot (r = 0.619) and to psychological relatedness (r = 0.581) whilst Neuroticism correlated negatively (r = -0.582) with mental relatedness with the robot. The results tentatively suggest that neither information about functionality nor direct repeated encounters are pivotal in changing attitudes toward robots in elderly citizens. This may reflect a cognitive congruence bias where the robot is experienced in congruence with initial attitudes, or it may support action-based explanations of cognitive dissonance reductions, given that robots, unlike computers, are not yet perceived as action targets. Specific personality traits may be indicators of attitude change relating to specific domains of social interaction. Implications and future directions are discussed. (shrink)

The robotics industry is growing rapidly, and to a large extent the development of this market sector is due to the area of social robotics – the production of robots that are designed to enter the space of human social interaction, both physically and semantically. Since social robots present a new type of social agent, they have been aptly classified as a disruptive technology, i.e. the sort of technology which affects the core of our current social practices and might lead (...) to profound cultural and social change. -/- Due to its disruptive and innovative potential, social robotics raises not only questions about utility, ethics, and legal aspects, but calls for “robo-philosophy” – the comprehensive philosophical reflection from the perspectives of all philosophical disciplines. This book presents the proceedings of the first conference in this new area, “Robo-Philosophy 2014 – Sociable Robots and the Future of Social Relations", held in Aarhus, Denmark, in August 2014. The short papers and abstracts collected here address questions of social robotics from the perspectives of philosophy of mind, social ontology, ethics, meta-ethics, political philosophy, aesthetics, intercultural philosophy, and metaphilosophy. -/- Social robotics is still in its early stages, but it is precisely now that we need to reflect its possible cultural repercussions. This book is accessible to a wide readership and will be of interest to everyone involved in the development and use of social robotics applications, from social roboticists to policy makers. (shrink)