These notes are meant to continue from the paper on Consistency, in proving number-theoretic theorems from the second-order arithmetical system called FFFF. Its ultimate target is Quadratic Reciprocity, although it introduces and proves some facts about the least common multiple at the start.

For those who have understood the solution to the Liarʼs Paradox and the Paradoxes of Predication, presented in A Comprehensive Solution to the Paradoxes and The Solution to the Liarʼs Paradox1, it will come as no surprise how the Berry Paradox should be solved. Nonetheless, the solution will be presented here in a short note, for completenessʼ sake.

Bertand's Postulate is proved in Peano Arithmetic minus the Successor Axiom.

I recently had the occasion to reread Naming and Necessity by Saul Kripke. NaN struck me this time, as it always has, as breathtakingly clear and lucid. It also struck me this time, as it always has, as wrong-headed in several major ways, both in its methodology and its content. Herein is a brief explanation why.

General Arithmetic is the theory consisting of induction on a successor function. Normal arithmetic, say in the system called Peano Arithmetic, makes certain additional demands on the successor function. First, that it be total. Secondly, that it be one-to-one. And thirdly, that there be a first element which is not in its image. General Arithmetic abandons all of these further assumptions, yet is still able to prove many meaningful arithmetic truths, such as, most basically, Commutativity and Associativity of Addition and (...) Multiplication, but also Lagrange’s Four-Square Theorem. Adding one more axiom, the one-oneness of succession, one can prove many more theorems, such as Quadratic Reciprocity and Fermat’s Little Theorem. By looking at arithmetic in this general setting, one receives a deeper understanding of the underlying structures. (shrink)

In "The Nature and Meaning of Numbers," Dedekind produces an original, quite remarkable proof for the holy grail in the foundations of elementary arithmetic, that there are an infinite number of things. It goes like this. [p, 64 in the Dover edition.] Consider the set S of things which can be objects of my thought. Define the function phi(s), which maps an element s of S to the thought that s can be an object of my thought. Then phi is (...) evidently one-to-one, and the image of phi is contained in S. Indeed, it is properly contained in S, because I myself can be an object of my thoughts and so belong to S, but I myself am not a mere thought. Thus S is infinite. (shrink)

How-many numbers, such as 2 and 1000, relate or are capable of expressing the size of a group or set. Both Cantor and Frege analyzed how-many number in terms of one-to-one correspondence between two sets. That is to say, one arrived at numbers by either abstracting from the concept of correspondence, in the case of Cantor, or by using it to provide an out-and-out definition, in the case of Frege.

A solution to the paradoxes has two sides: the philosophical and the technical. The paradoxes are, first and foremost, a philosophical problem. A philosophical solution must pinpoint the exact step where the reasoning that leads to contradiction is fallacious, and then explain why it is so.

As it is currently used, "foundations of arithmetic" can be a misleading expression. It is not always, as the name might indicate, being used as a plural term meaning X = {x : x is a foundation of arithmetic}. Instead it has come to stand for a philosophico-logical domain of knowledge, concerned with axiom systems, structures, and analyses of arithmetic concepts. It is a bit as if "rock" had come to mean "geology." The conflation of subject matter and its study (...) is a serious one, because in the end, one can lose sight of what one should be doing in the first place. Perhaps it is taking matters too literally, but it seems that there is something to be said for taking the term to represent X. Doing so and accepting the term to have some kind of significance, it is then natural to focus on the question of what a foundation of arithmetic should be; and, if one exists, what one is. Whatever the case, that is what shall be done in this paper. (shrink)

On the one hand, first-order theories are able to assert the existence of objects. For instance, ZF set theory asserts the existence of objects called the power set, while Peano Arithmetic asserts the existence of zero. On the other hand, a first-order theory may or not be consistent: it is if and only if no contradiction is a theorem. Let us ask, What is the connection between consistency and existence?

A solution to the Liar must do two things. First, it should say exactly which step in the Liar reasoning - the reasoning which leads to a contradiction - is invalid. Secondly, it should explains why this step is invalid.

I begin with a personal confession. Philosophical discussions of existence have always bored me. When they occur, my eyes glaze over and my attention falters. Basically ontological questions often seem best decided by banging on the table--rocks exist, fairies do not. Argument can appear long-winded and miss the point. Sometimes a quick distinction resolves any apparent difficulty. Does a falling tree in an earless forest make noise, ie does the noise exist? Well, if noise means that an ear must be (...) there to hear it, then the answer to the question is evidently "no." But if noise means that, if there were (counterfactually) someone there, then he would hear it, then just as obviously, the answer becomes "yes.". (shrink)

It might seem that three of Godel’s results - the Completeness and the First and Second Incompleteness Theorems - assume so little that they are reasonably indisputable. A version of the Completeness Theorem, for instance, can be proven in RCA0, which is the weakest system studied extensively in Simpson’s encyclopaedic Subsystems of Second Order Arithmetic. And it often seems that the minimum requirements for a system just to express the Incompleteness Theorems are sufficient to prove them. However, it will be (...) shown that a particular sub-system of Peano Arithmetic is powerful enough to express assertions about syntax, provability, consistency, and models, while being too weak to allow the standard proofs of the theorems to go through. An alternative proof is available for the First Incompleteness Theorem, but is of such a different nature that the import of the theorem changes. And there are no alternative proofs for (certainly) the Completeness and (apparently) the Second Incompleteness Theorems. It is therefore perfectly rational for someone to be skeptical about Godel’s results. (shrink)

The system called F is essentially a sub-theory of Frege Arithmetic without the ad infinitum assumption that there is always a next number. In a series of papers (Systems for a Foundation of Arithmetic, True” Arithmetic Can Prove Its Own Consistency and Proving Quadratic Reciprocity) it was shown that F proves a large number of basic arithmetic truths, such as the Euclidean Algorithm, Unique Prime Factorization (i.e. the Fundamental Law of Arithmetic), and Quadratic Reciprocity, indeed a sizable amount of arithmetic. (...) In particular, F proves some (but not all) of the Peano Axioms; that is, F proves the axioms of a sub-theory - call it FPA - of second-order Peano-Arithmetic. This short technical note will demonstrate that the converse also holds, in the following sense. F has the same language as second-order Peano Arithmetic except that, in addition, it has a two-place predicate symbol “Μ”. Then it is possible to provide a definition, indeed a reasonable definition, for “Μ” such that FPA proves all the axioms of F. So F and FPA effectively have the same proof-theoretic strength. In particular FPA, which lacks the Successor Axiom stating that every natural number has a successor, is able to prove the Euclidean Algorithm, Unique Prime Factorization, and Quadratic Reciprocity, indeed (again) a sizable amount of arithmetic. (shrink)

Because it is time-dependent, parallel computation is fundamentally different from sequential computation. Parallel programs are non-deterministic and are not effective procedures. Given the brain operates in parallel, this casts doubt on AI's attempt to make sequential computers intelligent.

Andrew Marvell’s “To His Coy Mistress” is one of the best known and most commented on poems in the English language. According to the critical consensus, the poem is a seduction gambit in the “Carpe Diem” tradition. Interpretive debate therefore revolves around the significance of the allusions and imagery of the poem, rather than its central meaning. Moving against the current, this article challenges the critical consensus that Marvell’s “To His Coy Mistress” is a poem that has seduction as (...) its main significance or implied intention. Reading the poem with attention to its ironic moments and theological references reveals that its allusions and imagery are systematically ambivalent. In the context of Marvell’s other poetry, especially “Dialogue of the Soul and the Body,” it becomes possible to show that “Coy Mistress” shares many features with these metaphysical meditations on mortality and spirituality. By making reference to psychoanalytic theory, the article then demonstrates the plausibility of a reading in which the poem aims to avoid, rather than engorge, sexual desire. The poem is a monument to repression, and a reminder of mortality, not a love lyric. (shrink)

The extent to which British Idealism was heavily influenced by Scots has been little noticed, yet not only were they at the forefront of introducing Hegel into Britain in the work of Ferrier, Carlyle, Hutcheson, Stirling and Edward Caird, but they were also distinctive in locating themselves in relation to the Scottish philosophical tradition they sought to extend. The Scottish Idealists, among them Edward Caird, David George Ritchie, Andrew Seth Pringle Pattison, William Mitchell, John Watson, and the Welshman Henry (...) Jones who found his spiritual home in Glasgow, comprised a formidable force and dominated the philosophical professoriate in Britain, Australia and Canada from the late nineteenth century to the years leading up to the First World War. Its main centres were St. Andrews, Glasgow and Edinburgh in Scotland, Cardiff in Wales, and Oxford in England. This collection of readings, the first of its kind, has been chosen with a view to displaying the variety, richness and strength of the Scottish Idealist tradition, beginning with an essay from the famous Essays in Philosophical Criticism, a book that set-out the future direction of enquiry for this group of thinkers who shared a 'common purpose or tendency'. Scottish Idealism was immensely spiritual in character and recognized no hard and fast distinctions between philosophy, religion, poetry and science. It was a formidable force in social and educational reform.. (shrink)

This paper explores the rhetoric of obstetric ultrasound technology as it relates to the abortion debate, specifically the interpretation given to ultrasound images by opponents of abortion. The tenor of the anti-abortion approach is precisely captured in the videotape, Ultrasound:A Window to the Womb. Aspects of this videotape are analyzed in order to tease out the assumptions about the (female) body and about the access to truth yielded by scientific technology (ultrasound) held by militant opponents of abortion. It is argued (...) that the ultrasound images do not offer transparent confirmation of the ontological status of the embryo and fetus. Rather, the window of ultrasound is constructed through a complex combination of visual and verbal devices: ultrasound images, photographic images, verbal argument, and emotional appeal. (shrink)

This paper examines the idea of objective phenomenology, or a way of understanding the phenomenal character of conscious experiences that doesn’t require one to have had the kinds of experiences under consideration. My central thesis is that structural facts about experience—facts that characterize purely how conscious experiences are structured—are objective phenomenal facts. I begin by precisifying the idea of objective phenomenology and diagnosing what makes any given phenomenal fact subjective. Then I defend the view that structural facts about experience are (...) objective. I also argue that structural facts about experience, despite being objective, nevertheless still give rise to an explanatory gap. (shrink)

Perception is riddled with cases of reliable misperception. These are cases in which a perceptual state is tokened inaccurately any time it is tokened under normal conditions. On the face of it, this fact causes trouble for theories that provide an analysis of perceptual content in non-semantic, non-intentional, and non-phenomenal terms, such as those found in Millikan (1984), Fodor (1990), Neander (2017), and Schellenberg (2018). I show how such theories can be extended so that they cover such cases without giving (...) up their core commitments. (shrink)

This is a discussion of the state of discussion on pragmatic reasons for belief.

This book brings together an international group of scholars to discuss the ramifications of Heidegger's Black Notebooks for philosophy and the humanities. In contrast to both those who seek to exonerate Heidegger and those who simply condemn him, they urge careful reading and rereading of his work to turn Heideggerian thought against itself.

The Stoics are traditionally regarded as the founders of propositional logic. However, this is not entirely correct. They developed a theory of inference from signs (omens). And their theory became a continuation of the logical technique of Babylonian divination (in particular, of Babylonian medical forecasting). The Stoic theory was not so much propositional logic as it was a technique of propositional logic for databases consisting of IF-THEN expert rules. In the Babylonian divination, each event has a positive or negative value (...) and all events are connected to each other. The Stoics also developed this idea and proposed a special modal logic in which logical determinism is considered an axiom. The paper reconstructs the sign-inference of the Stoics, as well as their modal logic. In particular, two Stoic squares of oppositions are proposed (for signs and for modal operators), which differ markedly from Aristotle’s square. (shrink)

While many aspects of cognition have been shown to be shared between humans and non-human animals, there remains controversy regarding whether the capacity to mentally time travel is a uniquely human one. In this paper, we argue that there are four ways of representing when some event happened: four kinds of temporal representation. Distinguishing these four kinds of temporal representation has five benefits. First, it puts us in a position to determine the particular benefits these distinct temporal representations afford an (...) organism. Second, it provides the conceptual resources to foster a discussion about which of these representations is necessary for an organism to count as having the capacity to mentally time travel. Third, it enables us to distinguish stricter from more liberal views of mental time travel that differ regarding which kind(s) of temporal representation is taken to be necessary for mental time travel. Fourth, it allows us to determine the benefits of taking a stricter or more liberal view of mental time travel. Finally, it ensures that disagreement about whether some species can mentally time travel is not merely the product of unrecognised disagreement about which temporal representation is necessary for mental time travel. We argue for a more liberal view, on the grounds that it allows us to view mental time travel as an evolutionarily continuous phenomenon, and to recognise that differences in the ways that organisms mentally time travel might reflect different temporal representations, or combinations thereof, that they employ. Our ultimate aim, however, is to create the conceptual framework for further discussion regarding what sorts of temporal representations are required for mental time travel. (shrink)

The aim of the Analytic of Concepts is to derive and deduce a set of pure concepts of the understanding, the categories, which play a central role in Kant’s explanation of the possibility of synthetic a priori cognition and judgment. This chapter is structured around two questions. First, what is a pure concept of the understanding? Second, what is involved in a deduction of a pure concept of the understanding? In answering the first, we focus on how the categories differ (...) from the pure forms of sensibility and examine whether they are known only to be the pure forms of human thinking or rather the forms of discursive cognition as such. In answering the second, we draw a distinction between the application and the exemplification of the categories and use it to identify different ways of understanding Kant’s project in the Transcendental Deduction of the Categories. These questions connect because the answer to the first determines how we should understand the kind of entitlement which is to be established in the Deduction. (shrink)

This chapter addresses an ambiguity in some of the literature on rational peer disagreement about the use of the term 'rational'. In the literature 'rational' is used to describe a variety of normative statuses related to reasons, justification, and reasoning. This chapter focuses most closely on the upshot of peer disagreement for what is rationally required of parties to a peer disagreement. This follows recent work in theoretical reason which treats rationality as a system of requirements among an agent's mental (...) states. It is argued that peer disagreement has either no, or a very limited, affect on what rationality requires of an agent in a given circumstance. This is in part because of difficulties generated by a novel example of evidence of evidence of p being evidence against p. This example calls into question the mechanisms whereby peer disagreement might affect what is rationally required of an agent. The chapter also reevaluates the importance of actual peer disagreement against the backdrop of prior expectations about whether disagreement is believed to be likely, arguing that peer disagreement is most likely to change what is rationally required of an agent when it is believed to be unlikely. (shrink)

This paper outlines a new pluralistic theory of normative reasons for belief, welfarist pluralism, which aims to explain how there can be basic alethic/epistemic reasons for belief and basic pragmatic/non-alethic reasons for belief that can combine to determine what one ought to believe. The paper shows how this non-derivative first-order pluralism arises from a purely welfarist account of the foundations of theoretical normativity, thereby combining foundational pragmatism with non-derivative pluralism about normative reasons for belief. In addition, this paper outlines how (...) welfarist pluralism provides a new and potentialy attractive account of the value of truth (or its indicators), namely that the value of truth (or its indicators) is its direct contribution to individuals' personal good or wellbeing. (shrink)

I argue that the following theses are both popular among evidentialists but also jointly inconsistent with evidentialism: 1) Time-Slice Mentalism: one’s justificational properties at t are grounded only by one’s mental properties at t; 2) Experience Ultimacy: all ultimate evidence is experiential; and 3) Sleep Justification: we have justified beliefs while we have dreamless, nonexperiential sleep. Although I intend for this paper to be a polemic against evidentialists, it can also be viewed as an opportunity for them to clarify their (...) views. Furthermore, the paper is not only relevant to evidentialists. For example, the arguments of this paper could give Time-Slice Mentalists a reason to deny evidentialism. (shrink)

This is a critical, but sympathetic, examination of the manifesto for naturalized metaphysics that forms the first chapter of James Ladyman and Don Ross's 2006 book, Every Thing Must Go, but it has wider implications than this description suggests.

This entry discusses the notion of a unit of normativity. This notion may be understood in two distinct ways. One way to understand a unit of normativity is as some particular type of assignment of normative status, e.g., a requirement, an ought, a reason, or a permission. A second way to understand a unit of normativity is as a measure of a quantity of normativity, perhaps associated with the numerical assignment given to the strength of reasons. This entry outlines some (...) basic differences among units of normativity in the first sense, noting that they vary slightly depending on whether one is talking about normativity in a more general or more robust sense. This entry also discusses in more detail the question of whether there might be a unit of normativity in the second sense. It discusses the relevant metaphysical questions. It also provides an explanation of why reasons can be assigned numerical strengths, even if there are no units of normativity in the sense of measurements of quantities of normativity. (shrink)

Source [1] Andrew E. P. Mitchell, Federica Galli, Sondra Butterworth. (2023). Editorial: Equality, diversity and inclusive research for diverse rare disease communities. Front. Psychol., vol. 14. doi:10.3389/fpsyg.2023.1285774. "It is also important to recognize that certain mental health disorders are classified as rare conditions and have their own cultural concepts of distress, as defined in the DSM-5 (American Psychiatric Association, 2013)" and require “equal attention and support for individuals and their families, both physically and emotionally”. [1].