Moran conceives of conscious belief as a conscious activity, rather than awareness of a mental state. Once conscious belief is understood in this way, the notion of suppressed belief becomes problematic. In this paper, I draw on the work of Merleau-Ponty to sketch an account of suppressed belief. I suggest that suppressed beliefs should not be understood as attitudes towards propositions. Instead, they should be conceived as ways of perceiving and interacting with the world that are out of keeping with how one repre-sents it as being.

The objective of this paper is to discuss the nature of nonconceptual, as opposed to conceptual, states and their content, by exploring the suggestion that the distinction between the conceptual and the nonconceptual be mapped onto the distinction between the linguistic and the nonlinguistic. This approach gives special relevance to our intuitions about the cognitive relationship between small children and adults, especially regarding the acquisition of concepts, in the course of normal cognitive development. Assuming that there is a developmental challenge to be met, the paper considers both the conceptualist and nonconceptualist strategies used to meet it; and concludes that conceptualism is a more satisfying option.

In my opinion, Richard Moran’s account of the connections between self-knowledge and intentional ac-tion presents a certain unresolved tension. On the one hand, the epistemic privilege of the first person derives from the fact that forming an intention is a matter of the subject endorsing a course of action. An en-dorsing subject is not a mere observer of her intentions. On the other hand, the transparency of endorsement is assimilated to the putative fact that an agent forms her intentions by reflecting on the reasons to make up her mind. The resulting picture is an extremely rationalistic account of intentional action. I will try to defend that this form of practical rationalism can be avoided without renouncing the basic intuitions behind Moran’s use of the notion of endorsement.

This paper is an examination and evaluation of McDowell’s criticisms of Davidson’s views on conceptual schemes and empiricism. I will argue that McDowell does not understand the real nature of Davidson’s arguments against the scheme-content dualism and that his new empiricist proposal fails to solve all the problems that old empiricism has traditionally raised. This is so because Davidson does not try to reject only a certain conception of experience by rejecting the dualism of scheme and content, but a way of thinking about meaning and knowledge that assumes a dualism that cannot be maintained.

In her book Abductive Reasoning Atocha Aliseda (2006) stresses the attention to the logical models of abduction, centering on the semantic tableaux as a method for extending and improving both the whole cognitive/philosophical view on it and on other more restricted logical approaches. I will provide further insight on two aspects. The first is re-lated to the importance of increasing logical knowledge on abduction: Aliseda clearly shows how the logical study on abduction in turn helps us to extend and modernize the classical and received idea of logic. The second refers to some ideas coming from the so-called distributed cognition and concerns the role of logical models as forms of cognitive exter-nalizations of preexistent in-formal human reasoning performances. The logical externalization in objective systems, communicable and sharable, is able to grant stable perspectives endowed with symbolic, abstract, and rigorous cogni-tive features. I will also emphasize that Aliseda especially stresses that this character of stability and objectivity of logical achievements are not usually present in models of abduction that are merely cognitive and epistemological, and of ex-treme importance from the computational point of view.

In this paper, we present a goal-directed proof procedure for abductive reasoning. This procedure will be compared with Aliseda’s approach based on semantic tableaux. We begin with some comments on Aliseda’s algorithms for computing conjunctive abductions and show that they do not entirely live up to their aims. Next we give a concise account of goal-directed proofs and we show that abductive explanations are a natural spin-off of these proofs. Finally, we show that the goal-directed procedure solves the problems we encountered in Aliseda’s algorithms.

Abduction can be intended as a special kind of deductive consequence. In fact a general trend is to consider it as a backward deduction with some additional conditions. However, there can be more than one kind of deduction, so that any definition of abduction must take that into account. From a logical perspec-tive the problem is precisely the formalization of conditions when the deductive consequence is fixed. In this paper, we adopt Makinson’s method to define new consequence relations, hence abduction is defined as a reverse relation corresponding to each one of such relations.

Abduction is a typical theme where logic and philosophy of science meet today: occasionally, with computer science as a go-between. This is just one instance of a broader study of ‘styles of reasoning’, dating back to Bolzano and Peirce. The resulting concern with ‘logical architecture’ moves us closer to cognitive science, and the dynamics of reasoning intertwined with learning and belief revision. The crucial process of self-correction involved here is usually triggered by others, and hence a shared target of logic and philoso-phy of science should be the phenomenon of ‘intelligent interaction’ between rational agents.

After a brief comparison of Aliseda’s account with different approaches to abductive reasoning, I relate abduction, as studied by Aliseda, to idealization, a notion which also occupies a very important role in scientific change, as well as to different ways of dealing with the growth of scientific knowledge understood as a particular kind of non-monotonic process. A particularly interesting kind of abductive reasoning could be that of finding an appropriate concretization case for a theory, originally revealed as extraordinarily success-ful but later discovered to be strictly false or only approximately or ideally true. I try to show this with the example of the Kepler-Newton relation. At the end of the paper, I give criteria in order to construe abduc-tive explanations in correspondence with a reasonable account of empirical progress.

Assuming, with Hasok Chang, that the history and philosophy of science can contribute to scientific knowledge, particularly when it is a matter of disposing of groundless or useless notions, I examine the case of the luminiferous ether, and seek to ascertain what factors may have kept it alive until 1905, when Einstein declared it superfluous.

Aliseda’s Abductive Reasoning is focused on the logical problem of abduction. My paper, in contrast, deals with the epistemic problems raised by this sort of inference. I analyze the relation between abduction and inference to the best explanation (IBE). Firstly a heuristic and a normative interpretation of IBE are distin-guished. The epistemic problem is particularly pressing for the latter interpretation, since it is devoid of content without specific epistemic criteria for separating acceptable explanations from those which are not. Then I discuss two different normative interpretations of IBE. I. Niiniliuoto favours a “probabilistic-confirmational” translation of explanatory merit while S. Psillos thinks that the insight of IBE is lost in a pure probabilistic format. My conclusion is that Aliseda’s theory of abduction fits better with a heuristic ac-count of IBE.

The motivation behind the collection of papers presented in this THEORIA forum on Abductive reasoning is my book Abductive Reasoning: Logical Investigations into the Processes of Discovery and Explanation. These contributions raise fundamental questions. One of them concerns the conjectural character of abduction. The choice of a logical framework for abduction is also discussed in detail, both its inferential aspect and search strategies. Abduction is also analyzed as inference to the best explanation, as well as a process of epistemic change, both of which chal-lenge the argument-like format of abduction. Finally, the psychological question of whether humans reason abduc-tively according to the models proposed is also addressed. I offer a brief summary of my book and then comment on and respond to several challenges that were posed to my work by the contributors to this issue.

Atocha Aliseda’s Abductive Reasoning (2006) gives a structural characterization of the “forward” explana-tory reasoning from a theory to observational data. This paper asks whether there are any interesting structural rules for the “backward” abductive reasoning from observations to explanatory theories. Ignoring statistical cases, a partial explication of abduction is converse deductive explanation: h is abducible from e iff h deductively explains e. This relation of abducibility trivially satisfies Converse Entailment (if h entails e, then h is abducible from e ), but it does not generally satisfy Converse Consequence (if h is abducible from e and g entails h, then g is abducible from e ), since deductive explanation is not always transitive.

This is an examination of similarities and differences between two recent models of abductive reasoning. The one is developed in Atocha Aliseda’s Abductive Reasoning: Logical Investigations into the Processes of Discovery and Evaluation (2006). The other is advanced by Dov Gabbay and the present author in their The Reach of Abduction: Insight and Trial (2005). A principal difference between the two approaches is that in the Gabbay-Woods model, but not in the Aliseda model, abductive inference is ignorance-preserving. A further differ-ence is that Aliseda reconstructs the abduction relation in a semantic tableaux environment, whereas the Woods-Gabbay model, while less systematic, is more general. Of particular note is the connection between abduction and legal reasoning.