Contemporary logicians continue to address problems associated with the existential import of categorical propositions. One notable problem concerns invalid instances of subalternation in the case of a universal proposition with an empty subject term. To remedy problems, logicians restrict first-order predicate logics to exclude such terms. Examining the historical origins of contemporary discussions reveals that logicians continue to make various category mistakes. We now believe that no proposition per se has existential import as commonly understood and thus it is unnecessary (...) to restrict first-order predicate logics to non-empty classes. After introducing the problem, we trace some nineteenth century treatments of the issue to locate a source of misconstruing propositional import in misconceptions of ‘implies’ and ‘affirms’ and name the process/product fallacy, along with the translation of categorical sentences using quantifiers and accommodating an empty class. Next we treat some metalogical matters to orient our discussion by which we provide a more precise nomenclature about ‘sentence’ and ‘proposition’ to correct previous misconceptions; here we uncover a common category mistake in respect of a proposition’s efficacy. The semantic distinction between agent and force is helpful in this connection. We conclude by showing that logicians have reinserted existence as a predicate, a position previously excised by Kant, and that the Frege-Russell ambiguity thesis applies only to relationships within a categorical sentence between grammatical predicate and subject. (shrink)

Populism is on the rise, especially in Western Europe. While it is often assumed that populist actors have a tendency for fallacious reasoning, this has not been systematically investigated. We analyze the use of informal fallacies by right-wing populist politicians and their representation in the media during election campaigns. We conduct a quantitative content analysis of press releases of right-wing populist parties and news articles in print media during the most recent elections in the United Kingdom and Switzerland in 2015. (...) The results show that fallacies are used in more than a third of all analyzed texts and overwhelmingly co-occur with populist key messages. Moreover, fallacies occur more often in populist parties’ press releases than in news articles and are more common in Switzerland compared to the United Kingdom. This study confirms the argument that populist actors use fallacies in combination with populist claims. (shrink)

This essay presents a skeleton of a potential conceptual framework for human flourishing in a free society. Its aim is to present a diagram that illustrates the ways in which its topics relate to one another and why they do. It argues for a plan of conceptualization rather than for the topics themselves. It emphasizes the interconnections among the components of the schema presented. It sees an essential interconnection between objective concepts, arguing that all of the disciplines of human action (...) can be integrated into a paradigm of human flourishing based on the nature of man and the world. (shrink)

The vision of natural kinds that is most common in the modern philosophy of biology, particularly with respect to the question whether species and other taxa are natural kinds, is based on a revision of the notion by Mill in A System of Logic. However, there was another conception that Whewell had previously captured well, which taxonomists have always employed, of kinds as being types that need not have necessary and sufficient characters and properties, or essences. These competing views employ (...) different approaches to scientific methodologies: Mill’s class-kinds are not formed by induction but by deduction, while Whewell’s type-kinds are inductive. More recently, phylogenetic kinds (clades, or monophyletic-kinds) are inductively projectible, and escape Mill’s strictures. Mill’s version represents a shift in the notions of kinds from the biological to the physical sciences. (shrink)

In this paper it is shown how plausible reasoning of the kind illustrated in the ancient Greek example of the weak and strong man can be analyzed and evaluated using a procedure in which the pro evidence is weighed against the con evidence using formal, computational argumentation tools. It is shown by means of this famous example how plausible reasoning is based on an audience’s recognition of situations of a type they are familiar with as normal and comprehensible in their (...) shared common knowledge. The paper extends previous work on this example by using three new multiagent argumentation schemes closely related to the scheme for argument from negative consequences. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Rhetoric 34.2 (2001) 93-112 [Access article in PDF] Enthymemes, Common Knowledge, and Plausible Inference Douglas Walton The study of enthymemes has always been regarded as important in logic, critical thinking, and rhetoric, but too often it is the formal or mechanistic aspect of it that has been in the forefront. This investigation will show that there is a kind of plausibilistic script-based reasoning, of a kind that (...) has mainly been studied in artificial intelligence, that should have a much more important role to play in the study of enthymemes. But then curiously, as will also be shown, this plausibilistic type of reasoning was familiar in the ancient world, to the Sophists, as well as to leading philosophers such as Plato and Aristotle. By linking this ancient notion of plausibility to the modern notion used in computer science, this investigation reveals an important basis for the enthymeme that has a type of logical structure in its own right, but also has an informal aspect.An enthymeme, in current usage, is an argument that has one or more premises, or possibly a conclusion, not explicitly stated in the text, but that needs to have these propositions explicitly stated to extract the complete argument from the text. Sometimes enthymemes are described as arguments with "missing premises." That vocabulary is awkward, however, because the nonexplicit statement that needs to be added can be a conclusion, at least in a minority of cases. To make the exposition below smoother, the term nonexplicit assumption will be used to cover either the case of a nonexplicit premise or that of a nonexplicit conclusion. The problem with enthymemes is that if the nonexplicit assumptions in an argument are supposed to be propositions used by the arguer (as opposed to just the propositions needed to make the argument structurally correct, according to some standard), reasonable people can have differences of opinion on what the nonexplicit assumptions are supposed to be. The problem is that filling in the missing parts of enthymemes depends on interpreting the natural language [End Page 93] in which the argument was put forward to try to determine what the speaker meant to say.The solution to the problem comes through the recognition that enthymemes rest not only on formal (structural) criteria, but also on informal criteria. One of the most important of these informal criteria is something often called "common knowledge" (Govier 1992; Freeman 1995). But as shown below in a set of selected case studies of enthymemes, "common knowledge" is not really a kind of knowledge at all. It is really plausibility, or eikos, something well known in the ancient world and often misleadingly translated as "probability." Curiously, Aristotle's original doctrine of the enthymeme was based on this notion of plausibility. This historical fact has often been a source of puzzlement and confusion, and sometimes it has even been taken to indicate a defect or contradiction in Aristotle's treatment of the enthymeme. However, the goal of this investigation is not primarily historical. It is to work out one of the most important required steps toward a solution to the problem of enthymemes. But to do this, it is necessary to come back to the ancient notion of plausible inference. 1. The problem with enthymemes Once you have any formal theory of inference, like syllogistic, for example, you will be confronted by cases of arguments in everyday discourse that meet all the requirements for a structurally correct inference except that some part or parts, usually a premise or a conclusion, is missing. By "missing" is meant that the proposition in question has not been explicitly stated in the text of discourse, even though it may be clear enough that the speaker (writer) was relying on it, or including it, as part of the argument. The classic example is the following inference: All men are mortal; therefore, Socrates is mortal. To evaluate such an argument, surely some account of the "hidden" or "missing" assumption needs to be taken. The problem with enthymemes (Burke 1985; Gough and Tindale 1985; Hitchcock 1985) is that, if given carte... (shrink)

The work of Hugh MacColl (1837–1909) suffered the same fate after his death as before it:despite being vaguely alluded to and in part even commended, on the whole it has remained an unknown quantity. Even worse, those of his ideas which have played a decisive role in the history of logic have been credited to his successors; this is especially the case with the definition of strict implication and the first formal development of formal modal logic. This paper takes an (...) initial step towards a rectification of this unfortunate misrepresentation, presenting a bibliography of MacColl’s most significant publications with particular regard to their reception. (shrink)

Bayesian reasoning has been applied formally to statistical inference, machine learning and analysing scientific method. Here I apply it informally to more common forms of inference, namely natural language arguments. I analyse a variety of traditional fallacies, deductive, inductive and causal, and find more merit in them than is generally acknowledged. Bayesian principles provide a framework for understanding ordinary arguments which is well worth developing.

Three distinctly different interpretations of Aristotle’s notion of a sullogismos in Prior Analytics can be traced: (1) a valid or invalid premise-conclusion argument (2) a single, logically true conditional proposition and (3) a cogent argumentation or deduction. Remarkably the three interpretations hold similar notions about the logical relationships among the sullogismoi. This is most apparent in their conflating three processes that Aristotle especially distinguishes: completion (A4-6)reduction(A7) and analysis (A45). Interpretive problems result from not sufficiently recognizing Aristotle’s remarkable degree of metalogical (...) sophistication to distinguish logical syntax from semantics and, thus, also from not grasping him to refine the deduction system of his underlying logic. While it is obvious that Aristotle most often uses ‘sullogimos’ to denote a valid argument of a certain kind, we show that at Prior Analytics A4-6, 7, 45 Aristotle specifically treats a sullogismos as an elemental argument pattern having only valid instances and that such a pattern then serves as a rule of deduction in his syllogistic logic. By extracting Aristotle’s understanding of three proof-theoretic processes, this paper provides new insight into what Aristotle thinks reasoning syllogistically is and, moreover, it resolves three problems in the most recent interpretation that takes a sullogismos to be a deduction. (shrink)

In the middle of last century metaphysics was widely criticized, ridiculed, and committed to the flames. During this period a handful of philosophers, against several anti-metaphysical trends, defended metaphysics and articulated novel metaphysical doctrines. Donald C. Williams was one of these philosophers. But while his contributions to metaphysics are well known his defence of metaphysics is not and yet it played a key part in the development and revival of metaphysics. In this paper I present his defence of metaphysics in (...) its historical context. I also show how his defence is relevant in response to recent attacks on metaphysics. (shrink)

Philosophy becomes speculative when it raises questions about the ultimate nature of being and thought. What does it mean to be? What does it mean to think? How are being and thought related? What does it mean to ask these questions? These questions have occupied a central place in philosophy throughout history, but have led a shadow existence in twentieth-century thought, which has cut the tie between reason and these fundamental questions, leaving the questions in the twilight, and reason instrumentalised. (...) A.N. Whitehead (1861-1947), one of the founders of analytic philosophy and co-author (with Bertrand Russell) of Principia Mathematica, is one of the few contemporary thinkers to have developed an explicit speculative philosophy. Unsurprisingly, his philosophy has played a marginal role in academic debates. In this study, the methodological foundation of Whitehead’s speculative thought is reconstructed. On the basis of a systematic and historical examination of the nature of the question of being, Whiteheads ontology of the event as the passage into novelty emerges in its full scope, allowing the reader to understand why and to what extent Whitehead has walked a different path than other contemporary thinkers. His philosophy contains a conception of reason that is not alien to newness and creativity while being more than procedural or pragmatic, and a mode of understanding existence that brings out the acuteness of freedom, value and legitimacy, as well as the unity of things, of thought and nature. In order to show what is really happening in this philosophy, the received interpretation of Whitehead’s ontology is radically dismantled. The central thought, that to be means to happen, is explained in a process of reiteration and gradual clarification, examining traditional philosophical problems in metaphysics and epistemology (on topics like: nature and matter, knowledge, categorical structure, freedom and necessity, truth and meaning, modality) from its perspective. What emerges is a philosophy in which the temporality of being, when taken seriously, changes the status of familiar problems and dualisms and offers possibilities for thought, which previously did not exist. Whitehead “hears” the classical questions of philosophy in a new way. Beyond the trenches of twentieth-century philosophy, Whitehead’s speculative thinking contains many elements that will be of value to those studying the foundations of thought today and looking for new directions. In a time when the dualism of nature and man is maintained cynically in our economies and dismantled, but only in a biologistic fashion and therefore only seemingly, as a cover-up, in science and philosophy, Whitehead’s new and creative way of hearing, and answering, old questions about ultimate concerns, when understood properly, is more up to date than ever before. (shrink)

My purpose in this chapter is to survey some of the principal approaches to inductive inference in the philosophy of science literature. My first concern will be the general principles that underlie the many accounts of induction in this literature. When these accounts are considered in isolation, as is more commonly the case, it is easy to overlook that virtually all accounts depend on one of very few basic principles and that the proliferation of accounts can be understood as efforts (...) to ameliorate the weaknesses of those few principles. In the earlier sections, I will lay out three inductive principles and the families of accounts of induction they engender. In later sections I will review standard problems in the philosophical literature that have supported some pessimism about induction and suggest that their import has been greatly overrated. In the final sections I will return to the proliferation of accounts of induction that frustrates efforts at a final codification. I will suggest that this proliferation appears troublesome only as long as we expect inductive inference to be subsumed under a single formal theory. If we adopt a material theory of induction in which individual inductions are licensed by particular facts that prevail only in local domains, then the proliferation is expected and not problematic. (shrink)

It is my intention in this thesis to demonstrate that there exists a clear and explicit formal relationship between the seemingly exclusive descriptions of spatio-temporal and purely temporal continuity, and further, that this relationship manifests itself within our most fundamental understanding of the physical world itself, namely; within our understanding of the identity, diversity and re-identification of material bodies. It may therefore be claimed that behind that cultural understanding which leads us to imagine that the physical world is located in (...) both space and time, whereas our thoughts and feelings are located in time alone, there lies a formal logical framework, or an explicit formal description of how being in space and time relates to being in time alone - leading us to wonder, perhaps, whether these two things are really as distinct as we might at first imagine. That I should then go on to apply to this analysis a philosophical interpretation of Bergson's conception of the relationship between the intuition and the intellect is of lesser importance - indicating as it does little more than my own philosophical inclinations. However, something will be gained, I hope, from this further exercise. Along the way it will allow me to clarify a number of technical points of which the general philosopher may be unaware; for example the unobservable nature of numerical identity and re-identification, the importance of the principle of special relativity to the topic of mind and the technical difficulties of claiming that mental events are 'in time' at all. Notwithstanding these latter points, however, the intentions of this work are predominantly analytical and are adequately described as an attempt to consolidate spatio-temporal and purely temporal description under a unified logical framework. (shrink)

Aristotle studies syllogistic argumentation in Sophistical Refutations and Prior Analytics. In the latter he focuses on the formal and syntactic character of arguments and treats the sullogismoi and non-sullogismoi as argument patterns with valid or invalid instances. In the former Aristotle focuses on semantics and rhetoric to study apparent sullogismoi as object language arguments. Interpreters usually take Sophistical Refutations as considerably less mature than Prior Analytics. Our interpretation holds that the two works are more of a piece than previously believed (...) and, indeed, that Aristotle's treatment of fallacious reasoning presupposes the results of the formal theory. (shrink)