Although in some contexts the notions of an ordinary argument’s presumption, assumption, and presupposition appear to merge into the one concept of an implicit premise, there are important differences between these three notions. It is argued that assumption and presupposition, but not presumption, are basic logical notions. A presupposition of an argument is best understood as pertaining to a propositional element (a premise or the conclusion) e of the argument, such that the presupposition is a necessary condition for the truth (...) of e or for a term in e to have a referent. In contrast, an assumption of an argument pertains to the argument as a whole in that it is integral to the reasoning or inferential structure of the argument. A logical assumption of an argument is essentially a proposition that must be true in order for the argument aside from that proposition to be fully cogent. Nothing that is both comparable and distinguishing can be said about presumptions of arguments. Rather, presumptions of arguments are distinctively conventional; they are introduced through conventional rules (e.g., those that concern how to treat promises). So not all assumptions and not all presuppositions of arguments are presumptions of those arguments, although all presumptions of arguments are either assumptions or presuppositions of those arguments. This account avoids making the (monological) notion of presumption vacuous and dissolving the distinction between assumption and presumption, which is a vulnerability of alternative views such as Hansen’s and Bermejo-Luque’s, as is shown. (shrink)

Under the rubric of understanding the problem of explainability of AI in terms of abductive cognition, I propose to review the lessons from AlphaGo and her more powerful successors. As AI players in Baduk have arrived at superhuman level, there seems to be no hope for understanding the secret of their breathtakingly brilliant moves. Without making AI players explainable in some ways, both human and AI players would be less-than omniscient, if not ignorant, epistemic agents. Are we bound to have (...) less explainable AI Baduk players as they make further progress? I shall show that the resolution of this apparent paradox depends on how we understand the crucial distinction between abduction and inference to the best explanation. Some further philosophical issues arising from explainable AI will also be discussed in connection with this distinction. (shrink)

This paper outlines an integrated approach to trust and relevance with respect to arguments: in particular, it is suggested that trust in relevance has a central role in argumentation. We first distinguish two types of argumentative relevance: internal relevance, i.e. the extent to which a premise has a bearing on its purported conclusion, and external relevance, i.e. a measure of how much a whole argument is pertinent to the matter under discussion, in the broader dialogical context where it is proposed. (...) Then, we argue that judgements of internal relevance heavily rely on trust, and that such trust, although occasionally misplaced , is nonetheless based on several reasons, and thus often justified, by either epistemic or pragmatic considerations. We conclude by sketching potential methods to formally model trust in argumentative relevance, and briefly discussing the technological implications of this line of research. (shrink)

In my opinion, it is only in the framework of a research dealing with abductive cognition that we can analyze important cognitive aspects of human and machine capacities. From the point of view of human capacities the phenomenological concept of anticipation, which is related to the problem of the spontaneous generation of spatiality and its three-dimensionality, will be central. I will describe that anticipations can be seen as types of visual and manipulative abduction and also fruitful to illustrate, in the (...) case of human and machine capacities, the respective role of two kinds of strategic reasoning: locked and unlocked abductive strategies, which characterize the basic cognitive pro- cedure of “reading ahead”. The specificity of these contrasting inferential strategies is also related to their potentiality in producing different kinds of hypothetical outcomes, which in turn represent dissimilar levels of knowledge creativity. This diversity is also fundamental to depict the special character, the kind of creativity, and the limits of current computational deep learning AI systems, such as AlphaGo, which realize abductive cognitive processes. (shrink)

The principle of charity is used in philosophy of language and argumentation theory as an important principle of interpretation which credits speakers with “the best” plausible interpretation of their discourse. I contend that the argumentation account, while broadly advocated, misses the basic point of a dialectical conception which approaches argumentation as discussion between two parties who disagree over the issue discussed. Therefore, paradoxically, an analyst who is charitable to one discussion party easily becomes uncharitable to the other. To overcome this (...) paradox, I suggest to significantly limit the application of the principle of charity depending on contextual factors. (shrink)

Recent work on conditional reasoning argues that denying the antecedent [DA] and affirming the consequent [AC] are defeasible but cogent patterns of argument, either because they are effective, rational, albeit heuristic applications of Bayesian probability, or because they are licensed by the principle of total evidence. Against this, we show that on any prevailing interpretation of indicative conditionals the premises of DA and AC arguments do not license their conclusions without additional assumptions. The cogency of DA and AC inferences rather (...) depends on contingent factors extrinsic to, and independent of, what is asserted by DA and AC arguments. arguments do not license their conclusions without additional assumptions. The cogency of DA and AC inferences rather depends on contingent factors extrinsic to, and independent of, what is asserted by DA and AC arguments. (shrink)

From a decision theoretic perspective, arguments stem from decisions made by arguers. Despite some promising results, this approach remains underdeveloped in argumentation theories, mostly because it is assumed to be merely descriptive. This assumption is mistaken: considering arguments as the product of decisions brings into play various normative models of rational choice. The challenge is rather to reconcile strategic rationality with other normative constraints relevant for argumentation, such as inferential validity and dialectical appropriateness.