A Logic For Inductive Probabilistic Reasoning

Inductive probabilistic reasoning is understood as the application of inference patterns that use statistical background information to assign (subjective) probabilities to single events. The simplest such inference pattern is direct inference: from “70% of As are Bs” and “a is an A” infer that a is a B with probability 0.7. Direct inference is generalized by Jeffrey’s rule and the principle of cross-entropy minimization. To adequately formalize inductive probabilistic reasoning is an interesting topic for artificial intelligence, as an autonomous system acting in a complex environment may have to base its actions on a probabilistic model of its environment, and the probabilities needed to form this model can often be obtained by combining statistical background information with particular observations made, i.e., by inductive probabilistic reasoning. In this paper a formal framework for inductive probabilistic reasoning is developed: syntactically it consists of an extension of the language of first-order predicate logic that allows to express statements about both statistical and subjective probabilities. Semantics for this representation language are developed that give rise to two distinct entailment relations: a relation ⊨ that models strict, probabilistically valid, inferences, and a relation that models inductive probabilistic inferences. The inductive entailment relation is obtained by implementing cross-entropy minimization in a preferred model semantics. A main objective of our approach is to ensure that for both entailment relations complete proof systems exist. This is achieved by allowing probability distributions in our semantic models that use non-standard probability values. A number of results are presented that show that in several important aspects the resulting logic behaves just like a logic based on real-valued probabilities alone.     

Extending probabilistic dynamic epistemic logic

This paper aims to extend in two directions the probabilistic dynamic epistemic logic provided in Kooi’s paper (J Logic Lang Inform 12(4):381–408, 2003) and to relate these extensions to ones made in van Benthem et al. (Proceedings of LOFT’06. Liverpool, 2006). Kooi’s probabilistic dynamic epistemic logic adds to probabilistic epistemic logic sentences that express consequences of public announcements. The paper (van Benthem et al., Proceedings of LOFT’06. Liverpool, 2006) extends (Kooi, J Logic Lang Inform 12(4):381–408, 2003) to using action models, but in both papers, the probabilities are discrete, and are defined on trivial σ-algebras over finite sample spaces. The first extension offered in this paper is to add a previous-time operator to a probabilistic dynamic epistemic logic similar to Kooi’s in (J Logic Lang Inform 12(4):381–408, 2003). The other is to involve non-trivial σ-algebras and continuous probabilities in probabilistic dynamic epistemic logic.     

Relational Science: A Synthesis

A synthesis of the two primary theory structures in Robert Rosen’s relational complexity, (1) relational entailment mapping based on category theory as described by Rosen and Louie, and (2) relational holism based on modeling relations, as described by Kineman, provides an integral foundation for relational complexity theory as a natural science and analytical method. Previous incompatibilities between these theory structures are resolved by re-interpreting Aristotle’s four causes, identifying final and formal causes as relations with context. Category theory is applied to introduce contextual entailment algebra needed to complete the synthesis. The modeling relation is represented as a recursive four-cause hierarchy, which is a unit of both whole and part analysis (a ‘holon’) that relates realized and contextual domains of nature as complementary inverse entailments between structure and function. Context is a non-localized domain of distributed potentials (models) for existence, as contrasted with the realized domain of localized interactive and measurable events. Synthesis is achieved by giving modeling relations an algebraic form in category theory and by expanding relational analysis to include contextual entailments. The revised form of analysis is applied and demonstrated to examine Rosen’s M-R diagram, showing that structure–function relations imply adaptive interaction with the environment, and that contextual relations imply three forms of the M-R entailment corresponding with the generally known three forms of life; Archaea, Bacteria, and Eukaryota, which can be represented by their holon diagrams. The result of this synthesis is a consistent foundation for relational science that should have important implications in many disciplines.     

Physicalism, Conceivability and Strong Necessities

David Chalmers’ conceivability argument against physicalism relies on the entailment from a priori conceivability to metaphysical possibility. The a posteriori physicalist rejects this premise, but is consequently committed to psychophysical strong necessities. These don’t fit into the Kripkean model of the necessary a posteriori, and they are therefore, according to Chalmers, problematic. But given semantic assumptions that are essential to the conceivability argument, there is reason to believe in microphysical strong necessities. This means that some of Chalmers’ criticism is unwarranted, and the rest equally afflicts the dualist. Moreover, given that these assumptions are independently plausible, there’s a general case to be made for the existence of strong necessities outside the psychophysical domain.     

Problems for Moral Twin Earth Arguments*

Terry Horgan and Mark Timmons have recently presented a series of papers in which they argue against what has come to be called the ‘new wave’ moral realism and moral semantics of David Brink, Richard Boyd, Peter Railton, and a number of other philosophers. The central idea behind Horgan and Timmons’s criticism of these ‘new wave’ theories has been extended by Sean Holland to include the sort of realism that drops out of response-dependent accounts that make use of an analogy between moral properties and secondary qualities. This paper argues that Holland’s extension depends crucially on the fact that his target is a direct response-dependent account of moral value. His argument does not work against such accounts of more basic normative notions such as ‘harm’ or ‘benefit’. And these more basic notions may then serve as the basic normative building blocks for an indirectly response-dependent moral theory. * Thanks to Mark Timmons for helpful and friendly comments on an earlier version of this paper, and also to an audience at the 2003 Pacific APA, and to the reviewers for this journal.     

Empirical Progress and Truth Approximation by the ‘Hypothetico-Probabilistic Method’

Three related intuitions are explicated in this paper. The first is the idea that there must be some kind of probabilistic version of the HD-method, a ‘Hypothetico-Probabilistic (HP-) method’, in terms of something like probabilistic consequences, instead of deductive consequences. According to the second intuition, the comparative application of this method should also be functional for some probabilistic kind of empirical progress, and according to the third intuition this should be functional for something like probabilistic truth approximation. In all three cases, the guiding idea is to explicate these intuitions by explicating the crucial notions as appropriate ‘concretizations’ of their deductive analogs, being ‘idealizations’. It turns out that the comparative version of the proposed HP-method amounts to the likelihood comparison (LC-) method applied to the cumulated evidence. This method turns out to be not only functional for probabilistic empirical progress but also for probabilistic truth approximation. The latter is based on a probabilistic threshold theorem constituting for this reason the analog of the deductive success theorem.

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Local contexts and local meanings

Stalnaker (1978) made two seminal claims about presuppositions. The most influential one was that presupposition projection is computed by a pragmatic mechanism based on a notion of ‘local context’. Due to conceptual and technical difficulties, however, the latter notion was reinterpreted in purely semantic terms within ‘dynamic semantics’ (Heim 1983). The second claim was that some instances of presupposition generation should also be explained in pragmatic terms. But despite various attempts, the definition of a precise ‘triggering algorithm’ has remained somewhat elusive. We discuss possible extensions of both claims. First, we offer a reconstruction of ‘local contexts’ which circumvents some of the difficulties faced by Stalnaker’s original analysis. We preserve the idea that local contexts are computed by a pragmatic mechanism that aggregates the information that follows from an incomplete sentence given the global context; but we crucially rely on a modified notion of entailment (‘R-entailment’), whose plausibility should be assessed on independent grounds. Second, we speculate that local contexts might prove necessary (though by no means sufficient) to understand how some presuppositions are triggered. In a nutshell, we suggest that a presupposition is triggered when the semantic contribution of an expression to its local context is in some sense ‘heterogeneous’. Without giving an analysis of the latter notion, we note that this architecture implies that presuppositions should be triggered on the basis of the meaning that an expression has relative to its local context (what we call its ‘local meaning’); we sketch some possible consequences of this analysis.     

An Admissible Semantics for Propositionally Quantified Relevant Logics

The Routley-Meyer relational semantics for relevant logics is extended to give a sound and complete model theory for many propositionally quantified relevant logics (and some non-relevant ones). This involves a restriction on which sets of worlds are admissible as propositions, and an interpretation of propositional quantification that makes ∀ pA true when there is some true admissible proposition that entails all p-instantiations of A. It is also shown that without the admissibility qualification many of the systems considered are semantically incomplete, including all those that are sub-logics of the quantified version of Anderson and Belnap’s system E of entailment, extended by the mingle axiom and the Ackermann constant t. The incompleteness proof involves an algebraic semantics based on atomless complete Boolean algebras.     

A Few More Useful 8-valued Logics for Reasoning with Tetralattice <Emphasis Type="Italic">EIGHT</Emphasis><Subscript>4</Subscript>

In their useful logic for a computer network Shramko and Wansing generalize initial values of Belnap’s 4-valued logic to the set 16 to be the power-set of Belnap’s 4. This generalization results in a very specific algebraic structure — the trilattice SIXTEEN ₃ with three orderings: information, truth and falsity. In this paper, a slightly different way of generalization is presented. As a base for further generalization a set 3 is chosen, where initial values are a — incoming data is asserted, d — incoming data is denied, and u — incoming data is neither asserted nor denied, that corresponds to the answer “don’t know”. In so doing, the power-set of 3, that is the set 8 is considered. It turns out that there are not three but four orderings naturally defined on the set 8 that form the tetralattice EIGHT ₄. Besides three ordering relations mentioned above it is an extra uncertainty ordering. Quite predictably, the logics generated by a–order (truth order) and d–order (falsity order) coincide with first-degree entailment. Finally logic with two kinds of operations (a–connectives and d–connectives) and consequence relation defined via a–ordering is considered. An adequate axiomatization for this logic is proposed.     

Statues and Lumps: A Strange Coincidence?

Puzzles about persistence and change through time, i.e., about identity across time, have foundered on confusion about what it is for ‘two things’ to be have ‘the same thing’ at a time. This is most directly seen in the dispute over whether material objects can occupy exactly the same place at the same time. This paper defends the possibility of such coincidence against several arguments to the contrary. Distinguishing a temporally relative from an absolute sense of ‘the same’, we see that the intuition, ‘this is only one thing’, and the dictum, ‘two things cannot occupy the same place at the same time’, are individuating things at a time rather than absolutely and are therefore compatible with coincidence. Several other objections philosophers have raised ride on this same ambiguity. Burke, originating what has become the most popular objection to coincidence, argues that if coincidence is possible there would be no explanation of how objects that are qualitatively the same at a time could belong to different sorts. But we can explain an object’s sort by appealing to its properties at other times. Burke’s argument to the contrary equivocates on different notions of ‘cross-time identity’ and ‘the statue’. From a largely negative series of arguments emerges a positive picture of what it means to say multiple things coincide and of why an object’s historical properties explain its sort rather than vice versa – in short, of how coincidence is possible.     

The Multidimensional Structure of ‘better than’

Axiomathes - According to the mixed lexicographic/additive account of ‘better than’ and similar aggregative value comparatives like ‘healthier than’, values are...     

Uncertainties

In contemporary science uncertainty is often represented as an intrinsic feature of natural and of human phenomena. As an example we need only think of two important conceptual revolutions that occurred in physics and logic during the first half of the twentieth century: (1) the discovery of Heisenberg’s uncertainty principle in quantum mechanics; (2) the emergence of many-valued logical reasoning, which gave rise to so-called ‘fuzzy thinking’. I discuss the possibility of applying the notions of uncertainty, developed in the framework of quantum mechanics, quantum information and fuzzy logics, to some problems of political and social sciences.     

Reasons and Entailment

What is the relation between entailment and reasons for belief? In this paper, I discuss several answers to this question, and I argue that these answers all face problems. I then propose the following answer: for all propositions p ₁,…,p _n and q, if the conjunction of p ₁,…, and p _n entails q, then there is a reason against a person’s both believing that p ₁,…, and that p _n and believing the negation of q. I argue that this answer avoids the problems that the other answers to this question face, and that it does not face any other problems either. I end by showing what the relation between deductive logic, reasons for belief and reasoning is if this answer is correct.     

Jewish pioneers on Canada’s prairies: The Lipton Jewish agricultural colony

This article offers a detailed analysis of the forces that shaped the Lipton colony in its 50-year existence, one of several dozen attempts to establish Jewish agricultural settlement on Canada’s Western prairies. Comparing both the particularities and the common features of Lipton with those of other colonies will allow strengthening some of the commonly accepted generalizations regarding these colonies, while at the same time showing other assumptions to be questionable or even myth. * A detailed discussion of the Jewish agricultural colonies in Western Canada may be found in Yossi Katz and John C. Lehr, The Last Best West: Essays on the Historical Geography of the Canadian Prairies (Jerusalem, 1999). Other sources discussing the colonies and the reasons for their establishment and ultimate disappearance are: Louis Rosenberg, “Jewish Agriculture in Canada” YIVO Annual of Social Sciences 5 (1950), 205–215; Louis Rosenberg, Canada’s Jews: A Social and Economic Study of the Jews of Canada in the 1930s (Montreal, 1931); Abraham J. Arnold, “The Contribution of the Jews to the Opening and Development of the West” Transactions of the Manitoba Historical Society Series 3 no. 3, (Winnipeg, 1968–’69).     

A puzzle about visualization

Visual imagination (or visualization) is peculiar in being both free, in that what we imagine is up to us, and useful to a wide variety of practical reasoning tasks. How can we rely upon our visualizations in practical reasoning if what we imagine is subject to our whims? The key to answering this puzzle, I argue, is to provide an account of what constrains the sequence in which the representations featured in visualization unfold—an account that is consistent with its freedom. Three different proposals are outlined, building on theories that link visualization to sensorimotor predictive mechanisms (e.g., “efference copies,” “forward models”). Each sees visualization as a kind of reasoning, where its freedom consists in our ability to choose the topic of the reasoning. Of the three options, I argue that the approach many will find most attractive—that visualization is a kind of “off-line” perception, and is therefore in some sense misrepresentational—should be rejected. The two remaining proposals both conceive of visualization as a form of sensorimotor reasoning that is constitutive of one’s commitments concerning the way certain kinds of visuomotor scenarios unfold. According to the first, these commitments impinge on one’s web of belief from without, in the manner of normal perceptual experience; according to the second, these commitments just are one’s (occurrent) beliefs about such generalizations. I conclude that, despite being initially counterintuitive, the view of visualization as a kind of occurrent belief is the most promising.     

Hempel’s Provisos and <Emphasis Type="Italic">Ceteris Paribus</Emphasis> Clauses

The problem of ceteris paribus clauses and Hempel’s problem of provisos are closely-related difficulties. Both challenge advocates of accounts of scientific theories involving laws understood as universal generalizations, and they have been treated as identical problems. Earman and Roberts argue that the problems are distinct. Towards arguing against them, I characterize the relationship between Hempel’s provisos and one way of expressing ceteris paribus clauses. I then describe the relationship between the problems attributed to the clauses, suggesting that they form a single problem-cluster. However, Hempel’s way of formulating provisos and discussing what they involve entangles provisos with the problem of skepticism. This creates a departure in Hempel’s discussion of provisos from the distinctive problem of vacuity which characterizes the problem of ceteris paribus clauses, though for different reasons than Earman and Roberts suggest.     

SHUTTING DRETSKE’S DOOR

Dretske proposes a theory of knowledge in terms of a theory of information, but wishes to deny that empirical knowledge settles the large question of scepticism. This leads him to deny the closure of knowledge under known entailment. In a recent paper J?ger argues that Dretske’s theory of information entails closure for knowledge, ‘at least for the kind of propositions here at issue’ (J?ger 2004:194). If J?ger is right, Dretske is seriously embarrassed and must give something up. In this paper I show that there are two flaws in J?ger’s argument. The principle of informational closure considered by J?ger is incompatible with Dretske’s theory of information, and J?ger’s argument that Dretske is committed to a certain kind of substitution instance of that principle of informational closure is invalid. I propose adequacy conditions on signalled information and use them to motivate a formulation of a general closure principle for signalled information. I show that Dretske’s account of information satisfies the adequacy conditions, but in a way which commits him to an instance of the general closure principle. I argue that Dretske is consequently committed to closure for some cases of knowledge for which he wishes to deny closure. Finally, I sketch how, on the basis of the closure principle to which Dretske is committed, J?ger’s broader argument may yet go through.