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Possible Worlds (possible + world)
Selected AbstractsCounterfactual Reasoning: Developing a Sense of "Nearest Possible World"CHILD DEVELOPMENT, Issue 1 2010Eva Rafetseder This study investigated at what point in development 3- to 6-year-old children begin to demonstrate counterfactual reasoning by controlling for fortuitously correct answers that result from basic conditional reasoning. Basic conditional reasoning occurs when one applies typical regularities (such as "If ,whenever' it doesn't rain the street is dry") to counterfactual questions (such as "If it had not rained, would the street be wet or dry?") without regard to actual events (e.g., if street cleaners had just been washing the street). In counterfactual reasoning, however, the conditional reasoning must be constrained by actual events (according to the "nearest possible world"). In situations when counterfactual reasoning and basic conditional reasoning would yield the same answers, even the youngest children gave mostly correct answers. However, tasks in which the 2 reasoning strategies resulted in different answers proved unusually difficult even for the older children. [source] Lewis, Causality, and Possible WorldsDIALECTICA, Issue 2 2000Graham White First page of article [source] SEMANTIC EXTERNALISM AND A PRIORI SELF-KNOWLEDGERATIO, Issue 2 2006Jussi Haukioja The argument known as the ,McKinsey Recipe' tries to establish the incompatibility of semantic externalism (about natural kind concepts in particular) and a priori self-knowledge about thoughts and concepts by deriving from the conjunction of these theses an absurd conclusion, such as that we could know a priori that water exists. One reply to this argument is to distinguish two different readings of ,natural kind concept': (i) a concept which in fact denotes a natural kind, and (ii) a concept which aims to denote a natural kind. Paul Boghossian has argued, using a Dry Earth scenario, that this response fails, claiming that the externalist cannot make sense of a concept aiming, but failing, to denote a natural kind. In this paper I argue that Boghossian's argument is flawed. Borrowing machinery from two-dimensional semantics, using the notion of ,considering a possible world as actual', I claim that we can give a determinate answer to Boghossian's question: which concept would ,water' express on Dry Earth?1 [source] Gödelian time-travel and anthropic cosmologyRATIO, Issue 2 2004Alasdair M. Richmond This paper looks at Kurt Gödel's causally-pathological cosmological models (derived from general relativity), in the light of anthropic explanations. If a Gödelian world is a possible world, could anthropic reasoning shed any light on whether or not our world is Gödelian? This paper argues that while there are some good anthropic reasons why our world ought to be Gödelian, too many observations suggest that our world can't possibly be Gödelian in fact. If Gödel's world is a possible one, anthropic teleology alone cannot explain why it isn't the world we inhabit. Furthermore, if our world were Gödelian, anthropic arguments against the existence of extraterrestrial intelligences would imply a bleak human future. En route, some general objections to relativistic causal pathologies are addressed and some anthropic arguments to the effect that Gödelian worlds couldn't sustain life are also addressed and dismissed. [source] Counterfactual Reasoning: Developing a Sense of "Nearest Possible World"CHILD DEVELOPMENT, Issue 1 2010Eva Rafetseder This study investigated at what point in development 3- to 6-year-old children begin to demonstrate counterfactual reasoning by controlling for fortuitously correct answers that result from basic conditional reasoning. Basic conditional reasoning occurs when one applies typical regularities (such as "If ,whenever' it doesn't rain the street is dry") to counterfactual questions (such as "If it had not rained, would the street be wet or dry?") without regard to actual events (e.g., if street cleaners had just been washing the street). In counterfactual reasoning, however, the conditional reasoning must be constrained by actual events (according to the "nearest possible world"). In situations when counterfactual reasoning and basic conditional reasoning would yield the same answers, even the youngest children gave mostly correct answers. However, tasks in which the 2 reasoning strategies resulted in different answers proved unusually difficult even for the older children. [source] On open-set lattices and some of their applications in semanticsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 12 2003Mouw-Ching Tjiok In this article, we present the theory of Kripke semantics, along with the mathematical framework and applications of Kripke semantics. We take the Kripke-Sato approach to define the knowledge operator in relation to Hintikka's possible worlds model, which is an application of the semantics of intuitionistic logic and modal logic. The applications are interesting from the viewpoint of agent interactives and process interaction. We propose (i) an application of possible worlds semantics, which enables the evaluation of the truth value of a conditional sentence without explicitly defining the operator "," (implication), through clustering on the space of events (worlds) using the notion of neighborhood; and (ii) a semantical approach to treat discrete dynamic process using Kripke-Beth semantics. Starting from the topological approach, we define the measure-theoretical machinery, in particular, we adopt the methods developed in stochastic process,mainly the martingale,to our semantics; this involves some Boolean algebraic (BA) manipulations. The clustering on the space of events (worlds), using the notion of neighborhood, enables us to define an accessibility relation that is necessary for the evaluation of the conditional sentence. Our approach is by taking the neighborhood as an open set and looking at topological properties using metric space, in particular, the so-called ,-ball; then, we can perform the implication by computing Euclidean distance, whenever we introduce a certain enumerative scheme to transform the semantic objects into mathematical objects. Thus, this method provides an approach to quantify semantic notions. Combining with modal operators Ki operating on E set, it provides a more-computable way to recognize the "indistinguishability" in some applications, e.g., electronic catalogue. Because semantics used in this context is a local matter, we also propose the application of sheaf theory for passing local information to global information. By looking at Kripke interpretation as a function with values in an open-set lattice ,,U, which is formed by stepwise verification process, we obtain a topological space structure. Now, using the measure-theoretical approach by taking the Borel set and Borel function in defining measurable functions, this can be extended to treat the dynamical aspect of processes; from the stochastic process, considered as a family of random variables over a measure space (the probability space triple), we draw two strong parallels between Kripke semantics and stochastic process (mainly martingales): first, the strong affinity of Kripke-Beth path semantics and time path of the process; and second, the treatment of time as parametrization to the dynamic process using the technique of filtration, adapted process, and progressive process. The technique provides very effective manipulation of BA in the form of random variables and ,-subalgebra under the cover of measurable functions. This enables us to adopt the computational algorithms obtained for stochastic processes to path semantics. Besides, using the technique of measurable functions, we indeed obtain an intrinsic way to introduce the notion of time sequence. © 2003 Wiley Periodicals, Inc. [source] Actuality and Modal RationalismPROCEEDINGS OF THE ARISTOTELIAN SOCIETY (HARDBACK), Issue 1pt3 2007Keith Hossack Modal rationalism is the doctrine that possible worlds are merely mental representations, and that necessity and apriority are the same thing. As an objection to modal rationalism, Kripke and others have proposed cases of the necessary that seem not to be a priori, and cases of the a priori that seem not to be necessary. I argue that the proposed counterexamples are unconvincing; in particular, there is nothing in the logic of the word ,actually' that need lead us to reject modal rationalism. [source] THE MODAL ARGUMENT FOR A PRIORI JUSTIFICATIONRATIO, Issue 2 2009Joachim Horvath Kant famously argued that, from experience, we can only learn how something actually is, but not that it must be so. In this paper, I defend an improved version of Kant's argument for the existence of a priori knowledge, the Modal Argument, against recent objections by Casullo and Kitcher. For the sake of the argument, I concede Casullo's claim that we may know certain counterfactuals in an empirical way and thereby gain epistemic access to some nearby, nomologically possible worlds. But I maintain that our beliefs about metaphysical necessities still cannot be justified empirically. Furthermore, I reject Casullo's deflationary thesis about the significance of such justification. Kitcher's most troublesome objection is that we can gain any modal justification whatsoever through testimony, i.e. in an experiential way. This can be countered by distinguishing between productive sources of justification, like perception, and merely reproductive sources, like testimony. Thus, some productive a priori source will always be needed somewhere.1 [source] IMPOSSIBLE WORLDS AND PROPOSITIONS: AGAINST THE PARITY THESISTHE PHILOSOPHICAL QUARTERLY, Issue 240 2010Francesco Berto Accounts of propositions as sets of possible worlds have been criticized for conflating distinct impossible propositions. In response to this problem, some have proposed to introduce impossible worlds to represent distinct impossibilities, endorsing the thesis that impossible worlds must be of the same kind; this has been called the parity thesis. I show that this thesis faces problems, and propose a hybrid account which rejects it: possible worlds are taken as concrete Lewisian worlds, and impossibilities are represented as set-theoretic constructions out of them. This hybrid account (1) distinguishes many intuitively distinct impossible propositions; (2) identifies impossible propositions with extensional constructions; (3) avoids resorting to primitive modality, at least so far as Lewisian modal realism does. [source] The Theses on Feuerbach as a political ecology of the possibleAREA, Issue 2 2009Alex Loftus This paper argues that Marx's Theses on Feuerbach offer a tremendous and yet neglected resource for work in political ecology and the production of nature. Whilst not calling for a dramatic shift in the way in which such work is conducted, the paper shows how the Theses offer a firm and concise foundation on which to base the ontological and epistemological claims of work on the politicised environment. Ontologically, nature is a differentiated unity, best understood as sensuous activity or practice. This fits well with Smith's claims that nature is produced, whilst not limiting production to capitalist activity. Environments are thereby made up of everyday activity. Subverting the apparent anthropocentrism of this claim, the paper shows how (as Gramsci recognised) the Theses on Feuerbach have an incipient sense of the socio-natural. Post-humanist critiques of Smith's (humanist) production of nature thesis are thereby disrupted. Production realises a differentiated unity of socio-natural relations. Epistemologically, the paper demonstrates how the Theses push political ecologists to construct knowledge claims from practical activity. An ecological politics thereby emerges from the situated knowledges of different actors. Building on this, the paper argues that Marx's ,notes to himself' give us a sense of possible worlds and possible ecologies beyond the topsy-turvy one we have made in the present. Through the concept of praxis evinced in the Theses, a vision of the engaged scholar activist, committed to learning about the world through changing it (and vice-versa), emerges. 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