Browsing by Author "Weiss, Bernhard"

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    The Fertility of Theories
    (2009) Segall, Robert; Weiss, Bernhard
    In addition to empirical adequacy and compatibility with other current theories, scientific theories are commonly judged on three criteria ' simplicity, elegance, and fertility. Fertility has received comparatively little attention in the philosophical literature. A definition of a certain sort of fertility, called P-fertility, proposed by Ernan McMullin, is that it consists in the capacity of a theory to be successfully modified over time to explain new experimental data or theoretical insights. McMullin made the major claim that he has a novel and perhaps the sole argument for Scientific Realism. His argument involves two strands (i) theories must be considered diachronically and it is an historical fact that long standing successful scientific theories are P-fertile, and (ii) the correct explanation of this fact is that these theories reflect the realities of a mind-independent world. A rebuttal of McMullin's position given in the literature is considered and rejected. His argument therefore requires further consideration. The plausible first strand of McMullin's argument is accepted for the purposes of discussion, and thus the observation requires explanation, either along McMullin's own lines or otherwise. The concept of diachronicity and the implications of accepting a diachronic view of scientific theories are considered. The identity of theory across time can be understood both from a Realist and an Anti-realist perspective via the concept of significant claims in the successive versions of the long standing successful theories. This defuses a possible objection to McMullin's argument, namely that by assuming diachronicity he begs the question against the Anti-realist. Explanations of the conjunction of success and P-fertility are examined from the perspective of Scientific Realism and the major current Anti-realist stances ' Entity Realism, Structural Realism, Instrumentalism, and Internal Realism. 3 To justify the second strand of McMullin's argument, a notion of the approximate truth or of the verisimilitude of theories is required. Inter alia it is argued that a distinction must be made between the approximate truth of a scientific theory and that of a simple assertion or a simple narrative. The concepts of the approximate truth of scientific theories and their verisimilitude are explored and some serious difficulties are identified. First, it is difficult to accommodate differences in respect as well as in degree in delineating the nature of an approximately true theory. Second, it is difficult to give a satisfactory account of the metric used to assess the verisimilitude of theories. It is argued that in any case no version of these concepts can adequately support the second strand of McMullin's thesis. This is because, at best, approximate truth and verisimilitude can only support a pragmatic claim ' the improved empirical adequacy of successive versions of the long standing theory. In contrast, McMullin's thesis requires that successor versions generally are better theories. Third, there is an intractable theory dependent weighting problem posed by the open ended nature of scientific theories in contrast with the closed narratives describing idealized models. The role of the approximate truth of scientific theories is explored, within the frameworks of Realism and Anti-realism, with regard to the possible responses to the existence of two highly successful, well corroborated, but incompatible theories ' general relativity and quantum mechanics. It is suggested that Scientific Realism itself, not only McMullin's argument for Scientific Realism, requires the notion of approximate truth or verisimilitude of theories. Putnam's Internal Realism is considered, and, if as I suggest, no adequate account of the concepts of the approximate truth or verisimilitude of scientific theories can be given, Internal Realism (which need not draw on these concepts because of its denial that there is a unique correct description of the world) is more plausible than the full blooded Scientific Realism advocated by McMullin, despite granting the claim of the historical observation of the conjunction between long standing successful theories and their P-fertility.
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    Introducing a Kantian interpretation of quantum physics : in accordance with Kant's philosophy of science in the Critique of the power of judgment, reinterpreted and reworked with special attention to the supersensible realm
    (2015) Mc Loud, Willem; Weiss, Bernhard; Ritchie Jack
    In this thesis I confront the problem of indeterminism in quantum physics. The first pioneers accepted indeterminism as part of their Copenhagen interpretation and it was incorporated in Von Neumann's formulation (as the "projection postulate"). But how deep does this indeterminism go? With the arrival of quantum physics, the idea that the world is fundamentally deterministic has been shattered. Redhead's work showed that the experimental confirmation of the violation of Bell's inequality means that determinism has broken down; he even formulated a version of the Bell inequality that is not dependent on local hidden variables and showed that the violation thereof negates even what might be called "stochastic" determinism - at least in the framework of the Lorentzian space-time manifold (Redhead 1987:83, 103). With the acceptance of non-determinism as part of our world, we are confronted with the question: How can the possibility of non-determinism be explained and how can it be reconciled with determinism in one coherent conceptualization of the world? I use the philosophy of science that Immanuel Kant developed in the Critique of the Power of Judgment to develop an answer to these questions. In this part of his philosophy of science Kant is concerned with the possibility and conceivability of a spontaneous (albeit effective) causality in nature's producing its products. Kant developed the idea of this causality in analogy to the achievement of human ends, conceptualizing it as a capacity that non-extended wholes and parts have to be realized as parts forming an aggregated whole in nature. An important feature of my approach is that I develop a new interpretation of Kant's philosophy as presented in his well-known Critique of Pure Reason. In contrast with the two-object and twoaspect views in Kantian interpretation, I argue that the noumenal realm refers to an ontologically distinct realm outside nature, problematically assumed. This agrees with Kant's view in the Critique of the Power of Judgment where it is conceptualized as the substratum of nature and forms a central part of his philosophy of science. It is only when the noumenal (supersensible) realm is conceptualized in this manner that spontaneous causality becomes not only logically possible, but also conceivable within the framework of his philosophy. In my Kantian interpretation of quantum physics his concept of nature is taken as referring to the "classical realm" (where the theories of relativity would apply). His non-extended wholes and parts, which belong to the supersensible realm, find application in superpositions of states, which I argue belong to an ontologically distinct realm - the pre-measurement "quantum realm". Since the classical and quantum realms are taken as ontologically distinct realms, there is no contradiction in ascribing two heterogeneous laws, namely of deterministic and spontaneous causality (which is manifest in the reduction of the wave packet), to these realms which are combined in one description in quantum mechanics. In my view spontaneous causality grounds a non-spatiotemporal potentiality which explains why superpositions of states have the ability to collapse to reduced states. I develop these ideas in the framework of the various interpretations of quantum mechanics.
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    Knowledge through communication : a response to the question of how testimony-based knowledge is possible
    (2014) Dewhurst, Thérèse; Weiss, Bernhard; Chapman, Dean; Jeremy Wanderer
    The aim of this thesis is to offer a response to the question of how it is that a hearer can get knowledge from testimony. The project has two main components. The first is to suggest that the obstacle to getting knowledge through testimony (the obstacle of epistemic vulnerability) is one that can be ignored. The second is to set out how it is that mere communication could be sufficient to explain how testimony can be a source of knowledge. The first component constitutes a proposal to reject the problem of testimony as it is usually conceived. Testimony is often seen to be epistemically distinct and interesting because of the apparent epistemic vulnerability posed by its being an indirect source of knowledge. Viewing the problem in this way has led most epistemologists to set out on a project of justification: the challenge is to explain how it is that hearing an assertion can be sufficient grounds for coming to know what is asserted. Whether one is a reductionist or a non-reductionist, the aim has been to establish that essential link between hearing a speaker assert that p, and p's being true. I will argue that seeing the problem of testimony as one of epistemic vulnerability is only inevitable if one has a particular view of knowledge. If we take knowledge to be a state metaphysically distinct from belief, a state not dependent on its justification to establish it as knowledge, then the indirectness of testimony does not inevitably result in a problem of vulnerability. The second component constitutes a positive explanation for the possibility of knowledge through testimony. I argue that (rather than seeking to justify our testimony-based beliefs) we ought to try to understand the mechanism whereby knowledge can be made available to a hearer simply by understanding an assertion. In this endeavour, I propose a certain theory of communication, such that understanding a communicative utterance entails coming to recognise the speaker's actual mental state. If successful communication gives the hearer access to the speaker's actual mental state, then successful communication can explain how understanding an assertion that p can get a hearer to know that p. I argue that correctly understanding an assertion that p entails coming to know that p. I defend the idea that the institution of communication explains how knowledge through testimony is possible.
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    Logic and the limits of explanation: the justification of deduction, Carrollian regress, logical validity and deductive inferential knowledge
    (2006) Chapman, Dean; Weiss, Bernhard
    This essay engages with the problems of the justification of deduction, Carrollian regress, and deductive inferential knowledge. Also, it is considered whether Lewis Carroll's tale of what the tortoise said to Achilles can be interpreted as suggesting an argument against the possibility of logically valid argument. Such an argument is presented and shown to be unsound. Any justification of one of our basic rules of deductive inference, such as modus ponens, will inevitably make use of the very rule it means to justify. It will be a 'rule-circular' argument and invite charges that it begs the question and 'keeps bad company'. Following Paul Boghossian, the contention in this essay is that a thinker need not know that the rule according to which a given inference proceeds is sound in order to be entitled to carry out the inference. Thus, a rule-circular argument for the soundness of modus ponens does not beg the question. Also, by a conceptual role semantics which takes as its starting point that of Boghossian, and with insights gained from Robert Brandom's inferentialism, it is argued that a thinker who carries out an inference which is meaning-constituting of some concept for her is entitled to that act of inference, in part because she is epistemically blameless in it. One of the ways to counter a Cartesian sceptic is to maintain that some of our beliefs are beliefs we are entitled to have no doubt about. To make that claim good, it is argued, one must hold two things: first, that some of our beliefs are such that we have conclusive evidence for them, evidence which guarantees their truth; and second, that for some of these beliefs, we know that we have conclusive evidence for them - there are infallibilist and intemalist constraints on the possibility of us having knowledge that is certain. Pace Boghossian, the contention here is that anyone who carries out an inference which is meaning-constituting of some concept for her, in fact knows that inference to be valid. It is argued that knowing of the validity of an inference is sufficient for being entitled to carry it out so that one can thereby come to have what is here called 'certain knowledge' of the truth of its conclusion, given the satisfaction of other broadly applicable constraints. Thus, it is held that a thinker who carries out a meaning-constituting inference can thereby come to have certain knowledge of the truth of its conclusion. The central undertaking of this essay is therefore to face up to the problem of Carrollian regress, insofar as the main difficulty it raises for us has to do with the possibility of deductive inferential knowledge. By a conceptual role semantics it is argued that the error committed in allowing ourselves to be led into Carrollian regress is that of distinguishing too sharply between practical and propositional knowledge. It is a proper requirement that a reasoner must know that an inference is valid in order to be entitled to carry it out; but we need not think further that such knowledge must be deployed with the proposition of whose truth the thinker knows as a premise of the argument for her conclusion. A belief can serve as the basis of a subject's carrying out of an act - such as an assertion, or an inference - and an inferer's belief that an inference is valid being a case of knowledge is sufficient for her being entitled to that act of inference. The account is satisfyingly an account of both epistemic inferential entitlement as well as the rationality of inference.
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    Logic and the limits of explanation: the justification of deduction, Carrollian Regress, logical validity, and deductive inferential knowledge
    (2006) Chapman, Dean; Weiss, Bernhard
    This essay engages with the problems of the justification of deduction, Carrollian regress, and deductive inferential knowledge. Also, it is considered whether Lewis Carroll's tale of what the tortoise said to Achilles can be interpreted as suggesting an argument against the possibility of logically valid argument. Such an argument is presented and shown to be unsound. Any justification of one of our basic rules of deductive inference, such as modus ponens, will inevitably make use of the very rule it means to justify. It will be a 'rule-circular' argument and invite charges that it begs the question and 'keeps bad company'. Following Paul Boghossian, the contention in this essay is that a thinker need not know that the rule according to which a given inference proceeds is sound in order to be entitled to carry out the inference. Thus, a rule-circular argument for the soundness of modus ponens does not beg the question. Also, by a conceptual role semantics which takes as its starting point that of Boghossian, and with insights gained from Robert Brandom's inferentialism, it is argued that a thinker who carries out an inference which is meaning-constituting of some concept for her is entitled to that act of inference, in part because she is epistemically blameless in it. One of the ways to counter a Cartesian sceptic is to maintain that some of our beliefs are beliefs we are entitled to have no doubt about. To make that claim good, it is argued, one must hold two things: first, that some of our beliefs are such that we have conclusive evidence for them, evidence which guarantees their truth; and second, that for some of these beliefs, we know that we have conclusive evidence for them - there are infallibilist and intemalist constraints on the possibility of us having knowledge that is certain. Pace Boghossian, the contention here is that anyone who carries out an inference which is meaning-constituting of some concept for her, in fact knows that inference to be valid.
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    On naturalistic saltation genealogies of content: an exploration of continuity & discontinuity in nonreductive diachronic explanations of content by Adam H. Schroeder supervised by University of Cape Town
    (2024) Schroeder, Adam; Weiss, Bernhard; Nefdt, Ryan
    Explanations involving the relationship between naturalism, normativity and intentional content are often plagued with difficulty. Incorporating any two in an explanation usually leads to challenges with integrating the third. My thesis aims to explore this tension, by considering an ambitious version of naturalistic explanation for the emergence of normative intentional content. I wish to cast doubt on this explanation by showing how it fails to alleviate the aforementioned tension. In fact, I will argue that this explanation is inconsistent owing to the inimical relationship between naturalism, normativity and intentional content. The explanation I will be considering is one amongst a variety of naturalistic explanations for solving the placement problem, i.e., how to locate intentional content, or items involving intentional content, “in a world exhaustively characterized in terms of the … collective posits of the … sciences.” 1 Traditionally, the answer to this location problem has been pursued by trying to naturalise content. In general, this involves providing some reductive relation between content and accepted natural facts in the hope of demonstrating that content can be understood in completely naturalistic non-contentful terms. This strategy has faced several difficulties in relation to normativity such as the disjunction problem and gerrymandering objection inter alia. As a prophylactic measure to deal with these difficulties, a strategy has recently come into vogue which forgoes attempts to provide purely reductive explanations of content; rather, it aims to explain how it is possible for content to nonreductively emerge in the natural world. In other words, it aims to explain the natural origins of content, rather than naturalise content. I name accounts fitting this strategy Naturalistic Saltation Genealogies of Content. Despite the benefits this strategy affords in avoiding the perennial objections naturalisation projects face in relation to normativity, my aim is to show that it is susceptible to its own set of difficulties due to the tension between naturalism, normativity and intentional content. More specifically, my aim is to show that the central assumptions of this strategy are inconsistent, and as a result, entail that they are discontinuous explanations of content. Alternatively put, these genealogical explanations cannot succeed in answering the placement problem. A consequence of this aim will be that if one is committed to the continuity of a naturalistic saltation genealogy of content, then this can be shown to implicitly entail the reduction of the normative to the nonnormative or the use of some non-naturalistic resources in explanation. The aim and consequence of my argumentation can by captured by the following slogan: (S) Naturalistic saltation genealogies of content are either discontinuous explanations or implicitly entail the reduction of the normative to the nonnormative or the rejection of naturalism. This is the same as saying that: (S*) Naturalistic saltation genealogies of content are either discontinuous explanations or self-defeating. Whereby ‘self-defeating' I mean that proponents of these genealogies unwittingly revert to other strategies for solving the placement problem – strategies that naturalistic saltation genealogies of content were precisely aimed at avoiding. This slogan will be demonstrated to be a product of the structural objection named the Continuity-Discontinuity Regress Argument. I.e., for every continuous naturalistic saltation genealogy, there is a Discontinuity Argument against it; and for every Discontinuity Argument there must be a sub-continuous naturalistic saltation genealogy constructed in response. This sets off a regress which results in an infinite regress of location problems.