Analysis of Knowledge, Assertion, Verification Daniele Chiffi Abstract: Since Plato’s Theatetus, propositional knowledge has been a perennial topic in philosophy. Even though the concept of knowledge and its analysis present such a long tradition, there is still the presence of “an extraordinary range of existing disagreements concerning conditions of knowing that should figure in an analysis of knowing” (Shope 2002, p. 25). According to the Platonic ‘tripartite analysis of knowledge’, knowledge is justified true belief. In this definition, the term truth reminds us of a realistic concept, that is, a mind-independent concept, while the justification of a belief reminds us of a mind- dependent concept1. The relation between mind and world is also a basic feature of the concept of assertion. This is so, since every assertion is based on an act of judgement which has to acknowledge the truth of a proposition, which speaks in itself of the world. Thus, the primary role is to linguistically express our judgements about the external world. Hence both knowledge and assertion regard the interplay between mind and world. On the one hand, one could claim that knowledge and assertion are independent concepts, but I am very sceptical of this, since they are both propositional attitudes, belong to the same linguistic category. On the other hand, one could maintain that knowledge and assertion are concepts of the same linguistic category, a view that I agree with, since they both aim to the truth of determined propositions. The same propositions express our thoughts on the world, and they are analysed in terms of beliefs and judgements, which are mind-dependent concepts. In the following sections I will try: i) to clarify how knowledge can be analysed in a fallibilist and probabilistic setting so that it can be connected to the concept of assertion in order to overcome the counterexamples that any previous analysis of knowledge have presented, ii) to determine the constitutive rule(s) of the act of assertion iii) to establish the consequences of the concepts thus analysed of assertion and knowledge for the verificationist programs in (constructive) mathematics and theory of meaning (notably in the dispute between Dummett and Hintikka on the correct logic of verificationism). Usually, the topic i) is mainly considered to belong to epistemology, the topic ii) to philosophy of language and iii) to constructive and/or epistemic logics. I hope that my unified view can open new horizons on these nested concepts. Notice that, differently from the proposals of a descriptive (or naturalized) epistemology, the present work has been written having in mind a normative framework for epistemology, within which it is possible to introduce criteria of justification in order to get a rational reconstruction about the concepts of knowledge and assertion. Namely, I am interested in presenting an explication of these concepts in order to make sense of the paradoxes that turn out to be connected with knowledge and assertion. Thus, I will not focus too much on the common use of these terms from a descriptive (and cognitive) point of view. Nevertheless, their rational reconstruction offers a proper linguistic treatment which can clarify the ambiguities (and paradoxes) of their use in natural language. Of course, different approaches to knowledge and assertion will determine a variety of interpretations and theories connected with these notions. Only after the assumption of a possible initial framework within which analysing a notion, one can apply a determined theory that turns out to be coherent with respect to the initial framework. In this sense, every theory implies some (partially hidden) philosophical and methodological assumptions, due also to external factors, that lead and determine the object of the research2. If so, then there exists the problem of comparing different approaches towards similar phenomena. My proposal indicates that only a rational reconstruction of a notion can handle the minimal features that every interpretation of that notion requires. Once the rational reconstruction has been fixed as a criterion of material adequacy, one can apply a particular theory (with its philosophical and empirical assumptions) which saves the phenomena explicated in the rational reconstruction. Of course, there can exists cases in which there is no agreement on the minimal features of the rational reconstructions of a notion, so, only in this case the requirement of the rational reconstruction can be overcome. Section 2 explores the problems of the analysis of knowledge and indicates my probabilistic treatment of the issue, while in Section 3 I show the validity and the limits of Williamson’s account of assertion and I claim that assertions are governed by two rules of assertions, namely the knowledge rule and the warrant rule. Moreover, I show the connection between these two rules and two different tendencies in the verificationist program, that I have called epistemic verificationism and pragmatic verificationism. In case of mathematical knowledge these two tendencies require different formalisms, as it follows in the analysis of the Dummett-Hintikka dispute. In Section 4, I will be back to the dichotomy between normative and descriptive epistemology, in order to reconsider the initial claims of the present work concerning the analysis of knowledge and assertion.