According to Adams's Thesis, the acceptability of an indicative conditional sentence goes by the conditional probability of its consequent given its antecedent. We test, for the first time, whether this thesis is descriptively correct and show that it is not; in particular, we show that it yields the wrong predictions for people's judgments of the acceptability of important subclasses of the class of inferential conditionals. Experimental results are presented that reveal an interaction effect between, on the one hand, the type of inferential connection between a conditional's antecedent and its consequent and, on the other, the judged acceptability of the conditional in relation to the conditional probability of its consequent given its antecedent. Specifically, these results suggest a family of theses, each pertaining to a different type of conditional, about how conditionals relate to the relevant conditional probabilities.

According to what is now commonly referred to as "the Equation" in the literature on indicative conditionals, the probability of any indicative conditional equals the probability of its consequent of the conditional given the antecedent of the conditional. Philosophers widely agree in their assessment that the triviality arguments of Lewis and others have conclusively shown the Equation to be tenable only at the expense of the view that indicative conditionals express propositions. This study challenges the correctness of that assessment by presenting data that cast doubt on an assumption underlying all triviality arguments.

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Evidence from reasoning tasks shows that promises and threats both tend to receive biconditional interpretations. They also both display high speaker control. On the face of it, the only difference seems to be the positive or negative signing of the consequent. In a promise, the speaker tries to persuade the hearer to do something by holding out the prospect of a particular reward; in a threat, the speaker tries to refrain the hearer from doing something by holding out the prospect of a particular punishment. This paper investigates the respects in which conditional promises and threats differ further by means of an inference task. The credibility of the consequent was manipulated in order to examine whether the acceptability ratings of inferences based on promises and on threats would be equally affected. The results of the inference task and an analysis of the reasons people give for their answers suggest that the credibility of promises is less affected by the use of excessive consequents than the credibility of threats. In other words, promise remains debt, whereas threat is another matter.

The difference between ‘car’ and ‘parce que’ is often explained in the literature by the type of causal relation (objective or subjective) that each connective prototypically conveys. Recent corpus studies have demonstrated, however, that this distinction does not hold in speech, and is fluctuating in writing. In this article, we present new empirical data to assess the status of this pair of connectives. In Experiment 1, we test French-speakers’ intuitions about ‘car’ and ‘parce que’ in a completion task, and compare these results with those of a similar experiment in Dutch. In Experiment 2, we measure the processing of objective and subjective causal relations containing ‘car’ and ‘parce que’ in an online reading experiment. Experiments 1 and 2 lead us to conclude that ‘car’ has to a large extent lost its specific procedural meaning. In the literature, the difference between ‘car’ and ‘parce que’ is also linked to a difference of register, ‘car’ being perceived as a formal equivalent of ‘parce que’. We assess the strength of this distinction in Experiment 3, by means of a completion task involving sentences from different registers. Results confirm the effect of register as a distinguishing factor between ‘car’ and ‘parce que’.