It is a platitude that when we reason, we often take things for granted, sometimes even justifiably so. The chemist might reason from the fact that a substance turns litmus paper red to that substance being an acid. In so doing, they take for granted, reasonably enough, that this test for acidity is valid. We ordinarily reason from things looking a certain way to their being that way. We take for granted, reasonably enough, that things are as they look Although (...) it is a platitude that we often take things for granted when we reason—whether justifiably or not—one might think that we do not have to. In fact, it is a natural expectation that were we not pressed by time, lack of energy or focus, we could always in principle make explicit in the form of premises every single presupposition we make in the course of our reasoning. In other words, it is natural to expect it to be true that presuppositionless reasoning is possible. In this essay, I argue that it is false: presuppositionless reasoning is impossible. Indeed, I think this is one of the lessons of a long-standing paradox about inference and reasoning known as Lewis Carroll’s (1985) regress of the premises. Many philosophers agree that Carroll’s regress teaches us something foundational about reasoning. I part ways about what it is that it teaches us. What it teaches us is that the structure of reasoning is constitutively presuppositional. (shrink)

In this paper, I motivate a puzzle about epistemic rationality. On the one hand, there seems to be something problematic about frequently changing your mind. On the other hand, changing your mind once is often permissible. Why do one-off changes of mind seem rationally permissible, even admirable, while constant changes seem quintessentially irrational? The puzzle of fickleness is to explain this asymmetry. To solve the puzzle, I propose and defend the Ratifiable Reasoning Account. According to this solution, as agents redeliberate, (...) they gain two types of evidence. First, they gain inductive evidence that they will not stably settle their belief. Second, this inductive evidence affords higher-order evidence that they are unreliable at assessing the matter at hand. The fact that fickle agents gain this higher-order evidence explains why fickleness can be epistemically—not just practically—irrational. In addition to solving the puzzle, my account captures a wide range of contextual factors that are relevant for our judgments. (shrink)

Suppositional reasoning can seem spooky. Suppositional reasoners allegedly (e.g.) “extract knowledge from the sheer workings of their own minds” (Rosa), even where the knowledge is synthetic a posteriori. Can literary fiction pull such a rabbit out of its hat? Where P is a work’s fictional ‘premise’, some hold that some works reason declaratively (supposing P, Q), imperatively (supposing P, do Q), or interrogatively (supposing P, Q?), and that this can be a source of knowledge if the reasoning is good. True, (...) I will argue, although only within the context of judicious critical interpretation. Further evident constraints include that the form of the suppositional reasoning needs to be declarative or imperative, and that the fictional ‘premise’ of the work needs to be a metaphysical counterfactual possibility, not merely a temporal counterfactual and not merely an epistemic possibility or probabilistic supposition. (shrink)

This thesis brings together two concerns. The first is the nature of inference—what it is to infer—where inference is understood as a distinctive kind of conscious and self-conscious occurrence. The second concern is the possibility of doxastic agency. To be capable of doxastic agency is to be such that one is capable of directly exercising agency over one’s beliefs. It is to be capable of exercising agency over one’s beliefs in a way which does not amount to mere self-manipulation. Subjects (...) who can exercise doxastic agency can settle questions for themselves. A challenge to the possibility of doxastic agency stems from the fact that we cannot believe or come to believe “at will”, where this in turn seems to be so because belief “aims at truth”. It must be explained how we are capable of doxastic agency despite that we cannot believe or come to believe at will. On the orthodox ‘causalist’ conception of inference for an inference to occur is for one act of acceptance to cause another in some specifiable “right way”. This conception of inference prevents its advocates from adequately seeing how reasoning could be a means to exercise doxastic agency, as it is natural to think it is. Suppose, for instance, that one reasons and concludes by inferring where one’s inference yields belief in what one infers. Such an inference cannot be performed at will. We cannot infer at will when inference yields belief any more than we can believe or come to believe at will. When it comes to understanding the extent to which one could be exercising agency in such a case the causalist conception of inference suggests that we must look to the causal history of one’s concluding act of acceptance, the nature of the act’s being determined by the way in which it is caused. What results is a picture on which such reasoning as a whole cannot be action. We are at best capable of actions of a kind which lead causally to belief fixation through “mental ballistics”. The causalist account of inference, I argue, is in fact either inadequate or unmotivated. It either fails to accommodate the self-consciousness of inference or is not best placed to play the very explanatory role which it is put forward to play. On the alternative I develop when one infers one’s inference is the conscious event which is one’s act of accepting that which one is inferring. The act’s being an inference is determined, not by the way it is caused, but by the self-knowledge which it constitutively involves. This corrected understanding of inference renders the move from the challenge to the possibility of doxastic agency to the above ballistics picture no longer tempting. It also yields an account of how we are capable of exercising doxastic agency by reasoning despite being unable to believe or come to believe at will. In order to see how such reasoning could amount to the exercise of doxastic agency it needs to be conceived of appropriately. I suggest that paradigm reasoning which potentially amounts the exercise of doxastic agency ought to be conceived of as primarily epistemic agency—agency the aim of which is knowledge. With inference conceived as suggested, I argue, it can be seen how to engage in such reasoning can just be to successfully exercise such agency. (shrink)

The article develops and justifies, on the basis of the epistemological argumentation theory, two central pieces of the theory of evaluative argumentation interpretation: 1. criteria for recognizing argument types and 2. rules for adding reasons to create ideal arguments. Ad 1: The criteria for identifying argument types are a selection of essential elements from the definitions of the respective argument types. Ad 2: After presenting the general principles for adding reasons (benevolence, authenticity, immanence, optimization), heuristics are proposed for finding missing (...) reasons, for deductive arguments, e.g., semantic tableaux are suggested. (shrink)

In this paper I deal with epistemological issues that stem from the hypothesis that reasoning is not only a means of transmitting knowledge from premise-beliefs to conclusion-beliefs, but also a primary source of knowledge in its own right. The idea is that one can gain new knowledge on the basis of suppositional reasoning. After making some preliminary distinctions, I argue that there are no good reasons to think that purported examples of knowledge grounded on pure reasoning are just examples of (...) premise-based inferences in disguise. Next, I establish what kinds of true propositions can to a first approximation be known on the basis of pure reasoning. Finally, I argue that beliefs that are competently formed on the basis of suppositional reasoning satisfy both externalist and internalist criteria of justification. (shrink)

Neste artigo trato da questão sobre o que torna uma dedução confiável. Uma resposta satisfatória a tal questão nos ajudaria a entender como dedução pode expandir ou gerar conhecimento. Eu exploro duas respostas a tal questão. A primeira faz uso da noção de acarretamento lógico-formal, enquanto que a segunda faz uso da noção de acarretamento metafísico. A última é superior à primeira, pois nos permite explicar a confiabilidade de uma classe mais ampla de deduções.

In this paper I explore alternative ways of addressing the infinite regress problem of inference, as it was depicted in Lewis Carroll’s ‘What the Tortoise said to Achilles’. Roughly put, the problem is that if a claim to the effect that one’s premises give support to one’s conclusion must itself be part of one’s premises, then an infinite regress of reasons ensues. I discuss some recent attempts to solve that problem, but I find all of them to be wanting. Those (...) attempts either require the reasoner to believe that her premises give support to her conclusion, or to take her premises to give support to her conclusion, where taking is not a doxastic attitude. I conclude that, on the face of the failure of those attempts to solve the problem, there is a strong prima facie case for allowing inference to be blind. (shrink)

Speakers of a natural language regularly form justified beliefs about what others are saying when they utter sentences of the language. What accounts for these justified beliefs? At one level, we already have a plausible answer: there is a perfectly good ordinary sense in which users of a language know what its sentences mean, and it is very plausible that the hearer’s knowledge of the meaning of S helps explain her justification for her belief about what is said by an (...) utterance of S. But what exactly does our knowledge of sentence meanings consist in? In this essay I advance and defend the view that we know the meanings of sentences in virtue of having a certain distinctive kind of know-how that I call inferential practical knowledge. I argue that this view provides the best explanation for the justification of our beliefs about what is said. In particular, it provides a better explanation than the more conventional and widely accepted view that we know the meaning of S in virtue of possessing the theoretical knowledge that S has such-and-such meaning. (shrink)

In ‘Reasoning and Regress’ I argued that inferring a conclusion from a set of propositions may simply consist in taking it that the conclusion follows from these propositions—thereby defusing familiar regress arguments. Sinan Dogramaci challenges the generality of this view, on the grounds that sometimes you may draw conclusions from no premisses that you believe. I respond by clarifying a distinction between the premisses of an argument from the reasons your conclusion is based upon. While suppositional reasoning may involve no (...) premisses in the former sense, it does not follow that it does not involve concluding something on the basis of reasons. This allows the view defended in ‘Reasoning and Regress’ to extend to suppositional reasoning. (shrink)

In this paper I address the question 'How is knowledge of logical truths possible'. The sought-after explanation should be independent of what the true story about logical truth is. In particular, I try to account for the epistemic warrant that is conferred upon logical beliefs when they are neither inferred from other beliefs nor grounded on empirical evidence or testimony. The need for such an account is motivated by the apparent failure of the notions ofanalyticity on the one hand and (...) intuition on the other in addressing the relevant question. I end up defending an account according to which warranted logical beliefs can be grounded on pure reasoning: they can be inferentially formed on the basis of pieces of suppositional reasoning. (shrink)

No presente artigo, trato da questão 'Como o conhecimento de verdades lógicas é possível?'. A explicação que procuro deveria ser independente de qual é a verdadeira teoria sobre verdades lógicas. Mais especificamente, tento explicar a natureza do status epistêmico conferido sob crenças em proposições lógicas quando tais crenças não são inferidas de outras crenças, ou sequer baseadas em evidência empírica ou testemunho. A necessidade de tal teoria é motivada pela aparente falha das noções de analiticidade e intuição em responder à (...) questão mencionada. Termino defendendo uma teoria de acordo com a qual crenças lógicas com status epistêmico positivo podem ser embasadas em puro raciocínio: elas podem ser formadas inferencialmente com base em raciocínio envolvendo suposições. (shrink)