I take up the four issues considered by Johnson-Laird, Byrne and Girotto in their reply to Politzer ( 2007 ). Based on the conceptual clarification which they adduce, it seems that the disagreement can be settled about the first one (truth functionality) and can be attenuated about the second one (the paradoxes of material implication). However, I maintain and refine my criticisms on the last two (negation and the probability of conditionals), backed up by considerations borrowed from the (...) perspective of the conditional probability semantics for conditionals. (shrink)
Most instantiations of the inference ‘y; so if x, y’ seem intuitively odd, a phenomenon known as one of the paradoxes of the material conditional. A common explanation of the oddity, endorsed by Mental Model theory, is based on the intuition that the conclusion of the inference throws away semantic information. We build on this explanation to identify two joint conditions under which the inference becomes acceptable: (a) the truth of x has bearings on the relevance of asserting y; and (...) (b) the speaker can reasonably be expected not to be in a position to assume that x is false. We show that this dual pragmatic criterion makes accurate predictions, and contrast it with the criterion defined by the mental model theory of conditionals, which we show to be inadequate. (shrink)
A study is reported testing two hypotheses about a close parallel relation between indicative conditionals, if A then B , and conditional bets, I bet you that if A then B . The first is that both the indicative conditional and the conditional bet are related to the conditional probability, P(B|A). The second is that de Finetti's three-valued truth table has psychological reality for both types of conditional— true , false , or void for indicative conditionals and win , lose (...) , or void for conditional bets. The participants were presented with an array of chips in two different colours and two different shapes, and an indicative conditional or a conditional bet about a random chip. They had to make judgements in two conditions: either about the chances of making the indicative conditional true or false or about the chances of winning or losing the conditional bet. The observed distributions of responses in the two conditions were generally related to the conditional probability, supporting the first hypothesis. In addition, a majority of participants in further conditions chose the third option, “void”, when the antecedent of the conditional was false, supporting the second hypothesis. (shrink)
This paper aims to make explicit the methodological conditions that should be satisfied for the Bayesian model to be used as a normative model of human probability judgment. After noticing the lack of a clear definition of Bayesianism in the psychological literature and the lack of justification for using it, a classic definition of subjective Bayesianism is recalled, based on the following three criteria: an epistemic criterion, a static coherence criterion and a dynamic coherence criterion. Then it is shown that (...) the adoption of this framework has two kinds of implications. The first one regards the methodology of the experimental study of probability judgment. The Bayesian framework creates pragmatic constraints on the methodology that are linked to the interpretation of, and the belief in, the information presented, or referred to, by an experimenter in order for it to be the basis of a probability judgment by individual participants. It is shown that these constraints have not been satisfied in the past, and the question of whether they can be satisfied in principle is raised and answered negatively. The second kind of implications consists of two limitations in the scope of the Bayesian model. They regard (1) the background of revision (the Bayesian model considers only revising situations but not updating situations), and (2) the notorious case of the null priors. In both cases Lewisâ rule is an appropriate alternative to Bayesâ rule, but its use faces the same operational difficulties. (shrink)
It is argued that, in the traditional subject-predicate sentence, two interpretations of the subject term coexist, one intensional and the other extensional, which explains the superficial difference between the traditional S-P relation and the predication of predicate logic. Data from psychological studies of syllogistic reasoning support the view that the contrast between predicate and argument is carried over to the traditional S-P sentence.
The Bayesian model has been used in psychology as the standard reference for the study of probability revision. In the first part of this paper we show that this traditional choice restricts the scope of the experimental investigation of revision to a stable universe. This is the case of a situation that, technically, is known as focusing. We argue that it is essential for a better understanding of human probability revision to consider another situation called updating (Katsuno & Mendelzon, 1992), (...) in which the universe is evolving. In that case the structure of the universe has definitely been transformed and the revision message conveys information on the resulting universe. The second part of the paper presents four experiments based on the Monty Hall puzzle that aim to show that updating is a natural frame for individuals to revise their beliefs. (shrink)
We elaborate on the approach to syllogistic reasoning based on “case identification” (Stenning & Oberlander, 1995; Stenning & Yule, 1997). It is shown that this can be viewed as the formalisation of a method of proof that dates back to Aristotle, namely proof by exposition ( ecthesis ), and that there are traces of this method in the strategies described by a number of psychologists, from St rring (1908) to the present day. We hypothesised that by rendering individual cases explicit (...) in the premises, the chance that reasoners would engage in a proof by exposition would be enhanced, and thus performance improved. To do so, we used syllogisms with singular premises (e.g., this X is Y ). This resulted in a uniform increase in performance as compared to performance on the associated standard syllogisms. These results cannot be explained by the main theories of syllogistic reasoning in their current state. (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)
Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock's (1987) distinction between 'rebutting' and 'undercutting' defeaters. 'Inferential' conditionals are shown to come in two varieties, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used as the (...) major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)
When a new piece of information contradicts a currently held belief, one has to modify the set of beliefs in order to restore its consistency. In the case where it is necessary to give up a belief, some of them are less likely to be abandoned than others. The concept of epistemic entrenchment is used by some AI approaches to explain this fact based on formal properties of the belief set (e.g., transitivity). Two experiments were designed to test the hypothesis (...) that contrary to such views, (i) belief is naturally represented by degrees rather than in an all-or-nothing manner, (ii) entrenchment is primarily a matter of content and not only a matter of form, and (iii) consequently prior degree of belief is a powerful factor of change. The two experiments used Elio and Pelletier's (1997) paradigm in which participants were presented with full simple deductive arguments whose conclusion was denied, following which they were asked to decide which premise to revise. (shrink)
We elaborate on the approach to syllogistic reasoning based on “case identification” (Stenning & Oberlander, 1995; Stenning & Yule, 1997). It is shown that this can be viewed as the formalisation of a method of proof that dates back to Aristotle, namely proof by exposition ( ecthesis ), and that there are traces of this method in the strategies described by a number of psychologists, from St rring (1908) to the present day. We hypothesised that by rendering individual cases explicit (...) in the premises, the chance that reasoners would engage in a proof by exposition would be enhanced, and thus performance improved. To do so, we used syllogisms with singular premises (e.g., this X is Y ). This resulted in a uniform increase in performance as compared to performance on the associated standard syllogisms. These results cannot be explained by the main theories of syllogistic reasoning in their current state. (shrink)
Although we endorse the primacy of uncertainty in reasoning, we argue that a probabilistic framework cannot model the fundamental skill of proof administration. Furthermore, we are skeptical about the assumption that standard probability calculus is the appropriate formalism to represent human uncertainty. There are other models up to this task, so let us not repeat the excesses of the past.
When is a conclusion worth deriving? We claim that a conclusion is worth deriving to the extent that it is relevant in the sense of relevance theory (Sperber & Wilson, 1995). To support this hypothesis, we experiment with ''indeterminate relational problems'' where we ask participants what, if anything, follows from premises such as A is taller than B, A is taller than C . With such problems, the indeterminate response that nothing follows is common, and we explain why. We distinguish (...) several types of determinate conclusions and show that their rate is a function of their relevance. We argue that by appropriately changing the formulation of the premises, the relevance of determinate conclusions can be increased, and the rate of indeterminate responses thereby reduced. We contrast these relevance-based predictions with predictions based on linguistic congruence. (shrink)
Language pragmatics is applied to analyse problem statements and instructions used in a few influential experimental tasks in the psychology of reasoning. This analysis aims to determine the interpretation of the task which the participant is likely to construct. It is applied to studies of deduction (where the interpretation of quantifiers and connectives is crucial) and to studies of inclusion judgment and probabilistic judgment. It is shown that the interpretation of the problem statements or even the representation of the task (...) as a whole often turn out to differ from the experimenter's assumptions. This has serious consequences for the validity of these experimental results and therefore for the claims about human irrationality based on them. (shrink)
The explanation of the suppression of Modus Ponens inferences within the framework of linguistic pragmatics and of plausible reasoning (i.e., deduction from uncertain premises) is defended. First, this approach is expounded, and then it is shown that the results of the first experiment of Byrne, Espino, and Santamar a (1999) support the uncertainty explanation but fail to support their counterexample explanation. Second, two experiments are presented. In the first one, aimed to refute one objection regarding the conclusions observed, the additional (...) conditional premise ( if N, C ) was replaced with a statement of uncertainty ( it is not certain that N ); the answers produced by the participants remained qualitatively and quantitatively similar in both conditions. In the second experiment, a fine-grained analysis of the responses to and justifications for an evaluation task was performed. The results of both experiments strongly supported the uncertainty explanation. (shrink)
The Bayesian model is used in psychology as the reference for the study of dynamic probability judgment. The main limit induced by this model is that it confines the study of revision of degrees of belief to the sole situations of revision in which the universe is static (revising situations). However, it may happen that individuals have to revise their degrees of belief when the message they learn specifies a change of direction in the universe, which is considered as changing (...) with time (updating situations). We analyze the main results of the experimental literature with regard to elementary qualitative properties of these two situations of revision. First, the order effect phenomenon is confronted with the commutative property. Second, an apparent new phenomenon is presented: the redundancy effect that is confronted with the idempotence property. Finally, results obtained in this kind of experimental situations are reinterpreted in the light of pragmatic analysis. (shrink)
El filósofo francés Alain Guy (La Rochelle, 1918 - Narbonne, 1998) dedicó por entero su vida al estudio de la filosofía española e hispanoamericana, dándola a conocer no sólo en el extranjero sino también en nuestro país.
This paper replies to Politzer’s ( 2007 ) criticisms of the mental model theory of conditionals. It argues that the theory provides a correct account of negation of conditionals, that it does not provide a truth-functional account of their meaning, though it predicts that certain interpretations of conditionals yield acceptable versions of the ‘paradoxes’ of material implication, and that it postulates three main strategies for estimating the probabilities of conditionals.
Recent models in quantum cosmology make use of the concept of imaginary time. These models all conjecture a join between regions of imaginary time and regions of real time. We examine the model of James Hartle and Stephen Hawking to argue that the various no-boundary attempts to interpret the transition from imaginary to real time in a logically consistent and physically significant way all fail. We believe this conclusion also applies to quantum tunneling models, such as that proposed by Alexander (...) Vilenkin. We conclude, therefore, that the notion of emerging from imaginary time is incoherent. A consequence of this conclusion seems to be that the whole class of cosmological models appealing to imaginary time is thereby refuted. (shrink)
Recent studies have shown that Einstein did not write the EPR paper and that he was disappointed with the outcome. He thought, rightly, that his own argument for the incompleteness of quantum theory was badly presented in the paper. We reconstruct the argument of EPR, indicate the reasons Einstein was dissatisfied with it, and discuss Einstein's own argument. We show that many commentators have been misled by the obscurity of EPR into proposing interpretations of its argument that do not accurately (...) represent Einstein's own views. Finally, we evaluate Einstein's own incompleteness argument, concluding that recent experimental findings have likely shown it to be unsound. (shrink)
This study tested the hypothesis that overt rehearsal is sufficient to explain enhanced memory associated with emotion by experimentally manipulating rehearsal of emotional material. Participants viewed two sets of film clips, one set of emotional films and one set of relatively neutral films. One set of films was viewed in each of two sessions, with approximately 1 week between the sessions. Participants were given a free recall test of all of films viewed approximately 1 week after the second session. Rehearsal (...) was manipulated by instructing one group of participants not to discuss the films with anyone (no talkgroup) and instructing a second group to discuss both sets of films with at least three people (forced talkgroup). A third group consisted of participants instructed not to discuss the films with anyone, but who did not comply with these instructions (talkersgroup). All groups recalled significantly more of the emotional films than the neutral films. Furthermore, the relative number of emotional and neutral films recalled did not differ significantly among the three groups. The results indicate that overt rehearsal is insufficient to explain the enhancing effects of emotion on memory. (shrink)
The European Union welfare standardsfor intensively kept pigs have steadilyincreased over the past few years and areproposed to continue in the future. It isimportant that the cost implications of thesechanges in welfare standards are assessed. Theaim of this study was to determine theprofitability of rearing pigs in a range ofhousing systems with different standards forpig welfare. Models were constructed tocalculate the cost of pig rearing (6–95 kg) in afully-slatted system (fulfilling minimum EUspace requirements, Directive 91630/EEC); apartly-slatted system; a high-welfare,straw-based system (...) (complying with the UK-basedRoyal Society for the Prevention of Cruelty toAnimals, Freedom Food standards) and afree-range system. The models were also used toassess the consequences of potential increasesin space allowance, and to estimate the cost ofrearing pigs under organic standards.The cost of rearing pigs ranged from92.0 p/kg carcass weight (cw) and 94.6 p/kgcw forthe partly-slatted and fully-slatted systems,to 98.8 p/kgcw and 99.3 p/kgcw for the FreedomFood and free-range systems respectively. Whenspace allowance was increased by 60% to levelsin a recent proposal to revise pig welfareDirective (91/630/EEC), the rearing costs wereunchanged for the free-range system but rose by4.6 p/kgcw for the fully-slatted system. Rearingcosts under organic standards were 31% higherthan in the free-range system. These resultssuggest that improved pig welfare can beachieved with a modest increase in cost. (shrink)
A test of directional entailment properties of classical quantifiers defined by the theory of generalized quantifiers (Barwise & Cooper 1981) is described. Participants had to solve a task which consisted of four kinds of inference. In the first one, the premise was of the form ‘Q–hyponym–verb–blank predicate’, where Q is a classical quantifier (e.g. ‘Some cats are [ ]’), and the question was to indicate what, if anything, can be concluded by filling the slots in ‘...–hyperonym–verb–blank predicate’ (e.g. ‘... animals (...) are [ ]’). The second kind of inference was the same, except that the hyperonym was in the premise and the hyponym in the conclusion. The third and fourth kinds of inference differed from the first two by the position of the hyperonym (respectively hyponym) which occupied the place of the predicate (e.g. ‘some [ ] are animals’). It was observed that if the directional entailment holds people respond accordingly in most cases and that if the entailment does not hold they correctly fail to produce it. These results provide elementary, but essential empirical support to this semantic approach to quantification, and are a prerequisite for its application to the study of reasoning with quantifiers. The implications for the psychology of reasoning are discussed. (shrink)
Machine-generated contents note: Preface -- 1 - Introduction -- Section One: Race Relations and Racial (In)justice in Colonial New Zealand -- 2 - Missionary and Maori, 1840-1865 -- 3 - Voiceless at Parihaka, 1881 -- 4 - Anti-Asian Racism in 'White' New Zealand -- Section Two: Legislating for Godliness -- 5 - Keeping Quiet About the Sabbath, 1860-1930 -- 6 - Sunday or Fun-day, 1931-1990 -- 7 - The Battle of the Booze -- 8 - Uncorking the Bottle: The Alcohol (...) Issue, 1920-2000 -- Section Three: In Search of Utopia -- 9 - Women Count in the 1890s -- 10 - Social Gospel and Socialism -- 11 - The 'Great Depression', 1929-1935 -- Section Four: Issues of War and Peace -- 12 - Fighting for Peace, 1899-1918 -- 13 - Versailles to Vietnam (and Beyond): Issues of War and Peace, 1919-1989 -- Section Five: Combating Racism at Home and Abroad -- 14 - Racism and Religion in Pukekohe, 1959 -- 15 - No Horis in the Scrum: Rugby and Race, 1959-1980 -- 16 - Tackling Apartheid: The 1981 Rugby Tour Controversy -- 17 - Race in the Eighties: 'Not One Acre More' at Bastion Point -- Section Six: The Place of Sex in Society -- 18 - Sex and Celluloid: The Film Censorship Debate, 1965- 1976 -- 19 - Abortion in the Back Streets: 1930 to 1960s -- 20 - Life versus Life: The 1970s Abortion Debate -- Section Seven: Issues of Gender and Sexuality -- 21 - Liberation at Last: Second-wave Feminism from 1970 -- 22 - Good as You? Gay or Sad? Debate over Homosexuality, 1960-1986 -- Section Eight: Toward the Future -- 23 - Hikoi and Hope: Social Justice in the 1990s -- 24 - Afterword -- Notes -- Abbreviations -- Bibliography -- Index. (shrink)
Hájek has recently presented the following paradox. You are certain that a cable guy will visit you tomorrow between 8 a.m. and 4 p.m. but you have no further information about when. And you agree to a bet on whether he will come in the morning interval (8, 12] or in the afternoon interval (12, 4). At first, you have no reason to prefer one possibility rather than the other. But you soon realise that there will definitely be a future (...) time at which you will (rationally) assign higher probability to an afternoon arrival than a morning one, due to time elapsing. You are also sure there may not be a future time at which you will (rationally) assign a higher probability to a morning arrival than an afternoon one. It would therefore appear that you ought to bet on an afternoon arrival. The paradox is based on the apparent incompatibility of the principle of expected utility and principles of diachronic rationality which are prima facie plausible. Hájek concludes that the latter are false, but doesn't provide a clear diagnosis as to why. We endeavour to further our understanding of the paradox by providing such a diagnosis. (shrink)
Unpublished draft. Let me know if you're interested to see it. See also my "Possibility and Permission? Intellectual Character, Inquiry, and the Ethics of Belief," forthcoming in H. Rydenfelt and S. Pihlstrom (eds.) William James on Religion (Palgrave McMillan “Philosophers in Depth” Series, 2012/2013).
The Cable Guy will definitely come between 8 a.m. and 4 p.m., and I can bet on one of two possibilities: that he will arrive between 8 and 12, or between 12 and 4. Since I have no more information, it seems (eminently) plausible to suppose the two bets are equally attractive. Yet Hajek has presented a tantalising argument that purports to show that the later interval is, initial appearances to the contrary, more choice worthy. In this paper, I rebut (...) the argument. (shrink)
We discuss the cable guy paradox, both as an object of interest in its own right and as something which can be used to illuminate certain issues in the theories of rational choice and belief. We argue that a crucial principle—The Avoid Certain Frustration (ACF) principle—which is used in stating the paradox is false, thus resolving the paradox. We also explain how the paradox gives us new insight into issues related to the Reflection principle. Our general thesis is that principles (...) that base your current opinions on your current opinions about your future opinions need not make reference to the particular times in the future at which you believe you will have those opinions, but they do need to make reference to the particular degrees of belief you believe you will have in the future. (shrink)
Review of Julian Savulescu, Ruud ter Meulen and Guy Kahane eds., Enhancing Human Capacities Content Type Journal Article Category Book Review Pages 1-4 DOI 10.1007/s12152-011-9148-y Authors Thomas Johnson, Graduate School of Humanities and Social Sciences, University of Melbourne, Parkville, VIC, Australia Journal Neuroethics Online ISSN 1874-5504 Print ISSN 1874-5490.
The Cable Guy is coming. You have to be home in order for him to install your new cable service, but to your chagrin he cannot tell you exactly when he will come. He will definitely come between 8.a.m. and 4 p.m. tomorrow, but you have no more information than that. I offer to keep you company while you wait. To make things more interesting, we decide now to bet on the Cable Guy’s arrival time. We subdivide the relevant part (...) of the day into two 4-hour long intervals, ‘morning’: (8, 12], and ‘afternoon’: (12, 4). You nominate an interval on which you will bet. If he arrives during your interval, you win and I will pay you $10; otherwise, I win and you will pay me $10. Notice that we stipulate that if he arrives exactly on the stroke of noon, then (8, 12] is the winning interval, since it is closed on the right; but we agree that this event has probability 0 (we have a very precise clock!). At first you think: obviously there is no reason to favour one interval over the other. Your probability distribution of his arrival time is uniform over the 8 a.m. – 4 p.m. period, and thus assigns probability 1/2 to each of the two 4-hour periods at issue. Whichever period you nominate, then, your expected utility is the same. The two choices are equally rational. But then you reason as follows. Suppose that you choose the morning interval. Then there will certainly be a period during which you will regard the other interval as.. (shrink)
This article reviews the importance of the French philosopher Guy Hocquenghem. An early theorist of radical homosexuality, Hocquenghem was prescient about the rightward pull on many in the ‘68 generation in France, including those who would go on to media fame in France for liberal critiques of their earlier political incarnations. Hocquenghem would die too soon in 1988, but not before leaving an influential corpus for those thinking non-heterosexist forms of desire and political communities.
