ABSTRACT A trivalent theory of indicative conditionals automatically enforces Stalnaker's thesis – the equation between probabilities of conditionals and conditional probabilities. This result holds because the trivalent semantics requires, for principled reasons, a modification of the ratio definition of conditional probability in order to accommodate the possibility of undefinedness. I explain how this modification is motivated and how it allows the trivalent semantics to avoid a number of well-known triviality results, in the process clarifying why these results hold for many (...) bivalent theories. In short, the slew of triviality results published in the last 40-odd years need not be viewed as an argument against Stalnaker's thesis: it can be construed instead as an argument for abandoning the bivalent requirement that indicative conditionals somehow be assigned a truth-value in worlds in which their antecedents are false. (shrink)

Over-simple internalist accounts of practical reasons imply that we cannot have reasons to become more rational, because they claim that we have a reason to φ only if we would have some desire to φ if we were fully rational. But if we were fully rational, we would have no desire to become more rational. Robert Johnson has recently argued that in their attempts to avoid this problem, existing versions of internalism yield reasons which do not have an appropriate connection (...) with potential explanations of action. I suggest that the problem is partly a result of failure to see that action-tokens are usually tokens of a wide variety of action-types, and that the internalist conditional need only be true of one of these types in order to justify a reason claim about the token. (shrink)

Truthmakers, truth conditions, and analyses are closely related, but distinct in rather important ways. A failure to properly appreciate their differences has led to some confusion regarding the role that possible worlds ought to play with respect to modality. Those philosophers who initially proposed the existence of possible worlds were understood as providing an analysis of modality. More recently, many have interpreted them as providing modal truthmakers. But, possible worlds are only suited to serve as truth conditions for modal truths. (...) My goals are as follows: First, to dispel this confusion by detailing the differences between these three concepts. Second, to apply the lesson learned to the famous Humphrey objection against possible worlds. While this objection, if successful, does undermine Lewisian modal realism, it only partially undermines ersatzism, and leaves available a route by which ersatzers may avoid the objection altogether. (shrink)

There is an increased interest in how excessive avoidance can diminish. Avoidance reduction is typically tested by using Extinction with Response Prevention protocols, where feared stimuli a...

The proposed heavy dependence on Pavlovian conditioning to account for social behavior confounds phylogenically and ontogenically selected behavior patterns and ignores the extension of the principle of selection by consequences from biological to learning theory. Instead of acknowledging operant relations, Domjan et al. construct vaguely specified mechanisms based upon anticipatory cost-benefit considerations that are not supported by the Pavlovian conditioning literature.

Women heard another person state attitudes that were either in high agreement or high disagreement with their own attitudes. The potency of an approach-avoidance dependent variable was compared with traditional dependent variables for this situation, ratings of inter-personal attraction. Eighty-five percent of those hearing high agreement volunteered to return to the laboratory to continue participation in the study at a later time. Nobody who heard high disagreement volunteered to return. This difference between the two treatment conditions was considerably greater (...) than the difference for ratings of attractiveness. It was concluded that the increased potency of the approach-avoidance measure came from its importance to the subjects and that approach-avoidance would be a good measure to use in comparing different predictions from the several theoretical positions that attempt to account for the effects of agreement and disagreement. (shrink)

Previous research showed that the repeated approaching of one stimulus and avoiding of another stimulus typically leads to more positive evaluations of the former stimuli. In the current study, we examined whether approach and avoidance training effects on evaluations of neutral stimuli can be modulated by introducing a regularity between the approach-avoidance actions and a positive or negative stimulus. In an AAT task, participants repeatedly approached one neutral non-word and avoided another neutral non-word. Half of the participants also (...) approached a negative fear-conditioned stimulus and avoided a conditioned safe stimulus. The other half of the participants avoided the CS+ and approached the CS−. Whereas participants in the avoid CS+ condition exhibited a typical AAT effect, participants in the approach CS+ condition exhibited a reversed AAT effect. These findings provide evidence for the malleability of the AAT effect when strongly valenced stimuli are approached or avoided. We discuss the practical and theoretical implications of our findings. (shrink)