Alexander George; Discussions: ‘Goldbach's Conjecture Can Be Decided in One Minute’: On an Alleged Problem for Intuitionism, Proceedings of the Aristotelian Soc.

Alexander George; Discussions: ‘Goldbach's Conjecture Can Be Decided in One Minute’: On an Alleged Problem for Intuitionism, Proceedings of the Aristotelian Soc.

Goldbach’s conjecture, if not read in number theory, but in a precise foundation theory of mathematics, that refers to the metaphysical ‘theory of the participation’ of Thomas Aquinas, poses a surprising analogy between the category of the quantity, within which the same arithmetic conjecture is formulated, and the transcendental/formal dimension. It says: every even number is ‘like’ a two, that is: it has the form-of-two. And that means: it is the composition of two units; not two equal (...) arithmetic units, but two different formal-transcendental units, which are, in arithmetic, two prime numbers. (shrink)

In this short note many conjectures on partitions of integers as summations of prime numbers are presented, which are extension of Goldbach conjecture.

So-called Neo-Russellians, such as Salmon, Braun, Crimmins, and Perry, hold that the semantic content of ‘ n is F ’ in a context c is the singular proposition ⟨ o, P ⟩, where o is the referent of the name n in c, and P is the property expressed by the predicate F in c. This is also known as the Neo-Russellian theory. Using truth ascriptions with names designating propositions, such as ‘Goldbach's conjecture’, in this paper, I will (...) argue that, together with highly plausible principles regarding a priori knowledge, the Neo-Russellian theory leads to unacceptable consequences. I will call this ‘the Goldbach puzzle’. Since the solution to the Goldbach puzzle cannot be to reject the discussed principles regarding a priori knowledge, the puzzle will undermine the Neo-Russellian theory. (shrink)

i. a poetic solution of the Goldbach Conjecture; ii. several responses to the Epimenides Paradox; iii. the volitional solution to Russell's Paradox.

In recent decades, experimental mathematics has emerged as a new branch of mathematics. This new branch is defined less by its subject matter, and more by its use of computer assisted reasoning. Experimental mathematics uses a variety of computer assisted approaches to verify or prove mathematical hypotheses. For example, there is “number crunching” such as searching for very large Mersenne primes, and showing that the Goldbach conjecture holds for all even numbers less than 2 × 1018. There are (...) “verifications” of hypotheses which, while not definitive proofs, provide strong support for those hypotheses, and there are proofs involving an enormous amount of computer hours, which cannot be surveyed by any one mathematician in a lifetime. There have been several attempts to argue that one or another aspect of experimental mathematics shows that mathematics now accepts empirical or inductive methods, and hence shows mathematical apriorism to be false. Assessing this argument is complicated by the fact that there is no agreed definition of what precisely experimental mathematics is. However, I argue that on any plausible account of ’experiment’ these arguments do not succeed. (shrink)

The purpose of this article is to defend Hume's claim that whatever is conceivable is possible from a criticism by William Kneale. Kneale argues that although a mathematician can conceive of the falsehood of the Goldbach conjecture, he does not conclude that it is not necessarily true. The author suggests that by taking into account Hume's distinction between intuitive and demonstrative knowledge, a revised version of his claim can be offered which is not open to Kneale's criticism.

Number theory abounds with conjectures asserting that every natural number has some arithmetic property. An example is Goldbach’s Conjecture, which states that every even number greater than 2 is the sum of two primes. Enumerative inductive evidence for such conjectures usually consists of small cases. In the absence of supporting reasons, mathematicians mistrust such evidence for arithmetical generalisations, more so than most other forms of non-deductive evidence. Some philosophers have also expressed scepticism about the value of enumerative inductive (...) evidence in arithmetic. But why? Perhaps the best argument is that known instances of an arithmetical conjecture are almost always small: they appear at the start of the natural number sequence. Evidence of this kind consequently suffers from size bias. My essay shows that this sort of scepticism comes in many different flavours, raises some challenges for them all, and explores their respective responses. (shrink)

By “epistemic modals,” I mean epistemic uses of modal words: adverbs like “necessarily,” “possibly,” and “probably,” adjectives like “necessary,” “possible,” and “probable,” and auxiliaries like “might,” “may,” “must,” and “could.” It is hard to say exactly what makes a word modal, or what makes a use of a modal epistemic, without begging the questions that will be our concern below, but some examples should get the idea across. If I say “Goldbach’s conjecture might be true, and it might (...) be false,” I am not endorsing the Cartesian view that God could have made the truths of arithmetic come out differently. I make the claim not because I believe in the metaphysical contingency of mathematics, but because I know that Goldbach’s conjecture has not yet been proved or refuted. Similarly, if I say “Joe can’t be running,” I am not saying that Joe’s constitution prohibits him from running, or that Joe is essentially a non-runner, or that Joe isn’t allowed to run. My basis for making the claim may be nothing more than that I see Joe’s running shoes hanging on a hook. (shrink)

Just as we can be more or less certain that there is extraterrestrial life or that Goldbach’s conjecture is correct, we can be more or less certain about normative matters, such as whether euthanasia is permissible or whether utilitarianism is true. However, accommodating the phenomenon of degrees of normative certitude is a difficult challenge for non-cognitivist and expressivist views, according to which normative judgements are desire-like attitudes rather than beliefs. Several attempts have been made on behalf of non-cognitivism (...) and expressivism to meet the challenge Studies in metaethics, Oxford University Press, Oxford, 2007; Sepielli in Philos Stud 160: 191–207, 2012; Eriksson and Francén Olinder in Aust J Philos 94: 719–735, 2016). These attempts have all been found wanting. Michael Ridge has recently offered a quasi-realist solution, according to which expressivists can say exactly what cognitivists say about certitude, including normative certitude. In this paper, we explain the basic problem and Ridge’s quasi-realist solution. We then argue that the quasi-realist account of normative certitude faces severe difficulties that do not arise for cognitivist accounts, according to which normative judgements are beliefs. (shrink)

I want to discuss a puzzle about the semantics of epistemic modals, like “It might be the case that” as it occurs in “It might be the case that Goldbach’s conjecture is false.”1 I’ll argue that the puzzle cannot be adequately explained on standard accounts of the semantics of epistemic modals, and that a proper solution requires relativizing utterance truth to a context of assessment, a semantic device whose utility and coherence I have defended elsewhere for future contingents (...) (MacFarlane.. (shrink)

In 1932, von Neumann proposed classifying the statistical behavior of differentiable systems. Joint work of B. Weiss and the author proved that the classification problem is complete analytic. Based on techniques in that proof, one is able to show that the collection of recursive diffeomorphisms of the 2-torus that are isomorphic to their inverses is $\Pi ^0_1$-hard via a computable 1-1 reduction. As a corollary there is a diffeomorphism that is isomorphic to its inverse if and only if the Riemann (...) Hypothesis holds, a different one that is isomorphic to its inverse if and only if Goldbach’s conjecture holds and so forth. Applying the reduction to the $\Pi ^0_1$-sentence expressing “ZFC is consistent” gives a diffeomorphism T of the 2-torus such that the question of whether $T\cong T^{-1}$ is independent of ZFC. (shrink)

SummaryThe platonist, in affirming the principle of bivalence for sentences for which there is no decision procedure, disconnects their truth‐conditions from conditions that would enable us to prove them ‐ as if Goldbach's conjecture, say, might just happen to be true. According to Dummett, what has gone wrong here is that the meaning of the relevant sentences has been conceived so as to go beyond what could be learned in learning to use them, or displayed in using them (...) competently. Dummett draws the general conclusion that accounts of meaning must traffic only in decidable circumstances. I suggest that Dummett can be right about platonism but wrong in this general conclusion: the centrality of decidable circumstances in competent use of language is a special feature of mathematical language. This means that someone who recoils from the anti‐realism constituted by Dummett's generalized anti‐platonism, in the case of, say, statements about other minds, need not be recoiling into a close analogue of platonism, as Dummett suggests. We can reinstate the intuitive idea that platonism goes wrong by inappropriately modelling the epistemology and metaphysics of mathematics on the epistemology and metaphysics of the natural world. And we make room for the suggestion that anti‐realism makes a converse mistake; in this vein, I propose a picture of Dummettian anti‐realism as a novel expression of familiar and suspect epistemological and metaphysical thoughts. (shrink)

_Conjectures and Refutations_ is one of Karl Popper's most wide-ranging and popular works, notable not only for its acute insight into the way scientific knowledge grows, but also for applying those insights to politics and to history. It provides one of the clearest and most accessible statements of the fundamental idea that guided his work: not only our knowledge, but our aims and our standards, grow through an unending process of trial and error.

Clayton and Stevens argue that political liberals should engage with the religiously unreasonable by offering religious responses and showing that their religious views are mistaken, instead of refusing to engage with them. Yet they recognize that political liberals will face a dilemma due to such religious responses: either their responses will alienate certain reasonable citizens, or their engagements will appear disingenuous. Thus, there should be a division of justificatory labour. The duty of engagement should be delegated to religious citizens. In (...) this comment, I will argue that the division of justificatory labour is indefensible. This dilemma can be avoided if politicians and political philosophers correctly use conjecture, a form of discourse that involves non-public reason. As a conditional response, conjecture avoids alienating any reasonable citizens. Also, if conjecture is given in a sincere and open-minded manner, then the problem of disingenuousness can be overcome. My comment concludes that while the engagement of politicians and political philosophers does not necessarily jeopardize overlapping consensus, they should be permitted, or perhaps even required, to engage with the religiously unreasonable due to the natural duty of justice. (shrink)

_Conjectures and Refutations_ is one of Karl Popper's most wide-ranging and popular works, notable not only for its acute insight into the way scientific knowledge grows, but also for applying those insights to politics and to history. It provides one of the clearest and most accessible statements of the fundamental idea that guided his work: not only our knowledge, but our aims and our standards, grow through an unending process of trial and error.

In this paper I argue that, in at least two cases - his discussions of the temporal precedence o f polytheism over monotheism and of the origins of civil society - we see Hume consigning to historical development certain aspects of reason which, as a comparison with Locke will show, have sometimes been held to be uniform. In the first of these cases Hume has recourse to claims about the general historical development of human thought. In the second case, the (...) origin of the civil institution of justice and government is not linked directly to external circumstances and the principles of human nature, as it is in contractarian theories, but makes a detour through the historical acquisition of certain concepts. Because Hume's position does not conform in any simple sense to Dugald Stewart's 'incontrovertible logical maxim' that the capacities of the human mind have been the same in all ages, Stewart's account of the method of conjectural history is, in any simple sense, inadequate as a description of Hume's practice. (shrink)

We show that both Rado's Conjecture and strong Chang's Conjecture imply that there are no special ℵ2-Aronszajn trees if the Continuum Hypothesis fails. We give similar result for trees of higher heights and we also investigate the influence of Rado's Conjecture on square sequences.

The way in which knowledge progresses, and especially our scientific knowledge, is by unjustified anticipations, by guesses, by tentative solutions to our problems, by conjectures. These conjectures are controlled by criticism: that is, by attempted refutations, which include severely critical tests. They may survive these tests; but they can never be positively justified: they can neither be established as certainly true nor even as 'probable'. Criticism of our conjectures is of decisive importance: by bringing out our mistakes it makes us (...) understand the difficulties of the problems which we try to solve. This is how we become better acquainted with our problem, and able to propose more mature solutions: the very refutation of a theory - that is, of a tentative solution to our problem - is always a step forward that takes us nearer the truth. And this is how we can learn from our mistakes. As we learn from our mistakes our knowledge grows, even though we may never know - that is, know for certain. Since our knowledge can grow, there can be no reason here for despair of reason. And since we can never know for certain, the can be no authority here for any claim to authority, for conceit over our knowledge, or for smugness. The essays and lectures of which this book is composed apply this thesis to many topics, ranging from problems of the philosophy and history of the physical and social sciences to historical and political problems. (shrink)

We show that both Rado's Conjecture and strong Chang's Conjecture imply that there are no special ℵ2-Aronszajn trees if the Continuum Hypothesis fails. We give similar result for trees of higher heights and we also investigate the influence of Rado's Conjecture on square sequences.

The Conjectural Body combines continental philosophy with musicology, popular music studies, and feminist, critical race, and postcolonial theories to offer a unique perspective on issues of gender, race, and the philosophy of music. It is one of the few books in philosophy to take popular music seriously, and is one of the few books in continental feminism to privilege music over the visual.

A conjectural inference is proposed, aimed at producing conjectural theorems from formal conjectures assumed as axioms, as well as admitting contradictory statements as conjectural theorems. To this end, we employ Paraconsistent Informational Logic, which provides a formal setting where the notion of conjecture formulated by an epistemic agent can be defined. The paraconsistent systems on which conjectural deduction is based are sequent formulations of the C-systems presented in Carnielli-Marcos [CAR 02b]. Thus, conjectural deduction may also be considered to be (...) a tool for investigating the properties of paraconsistency in general. (shrink)

This classic remains one of Karl Popper's most wide-ranging and popular works, notable not only for its acute insight into the way scientific knowledge grows, but also for applying those insights to politics and to history.

Sir Karl Popper is well known for explicating science in falsificationist terms, for which his degree of corroboration formalism, C(h,e,b), has become little more than a symbol. For example, de Queiroz and Poe in this issue argue that C(h,e,b) reduces to a single relative (conditional) probability, p(e,hb), the likelihood of evidence e, given both hypothesis h and background knowledge b, and in reaching that conclusion, without stating or expressing it, they render Popper a verificationist. The contradiction they impose is easily (...) explained--de Queiroz and Poe fail to take account of the fact that Popper derived C(h,e,b) from absolute (logical) probability and severity of test, S(e,h,b), where critical evidence, p(e,b), is fundamental. Thus, de Queiroz and Poe's conjecture that p(e,hb) = C(h,e,b) is refuted. Falsificationism, not verificationism, remains a fair description of the parsimony method of inference used in phylogenetic systematics, not withstanding de Queiroz and Poe's mistaken understanding that "statistical" probability justifies that method. Although de Queiroz and Poe assert that maximum likelihood has the power "to explain data", they do not successfully demonstrate how causal explanation is achieved or what it is that is being explained. This is not surprising, bearing in mind that what is assumed about character evolution in the accompanying likelihood model M cannot then be explained by the results of a maximum likelihood analysis. (shrink)

In this paper art history and visual studies, the disciplines that study visual culture, are presented as a field whose conjectural paradigm can be used to understand the epistemic problems associated with abduction. In order to do so, significant statements, concepts and arguments from the work of several specialists in this field have been highlighted. Their analysis shows the fruitfulness and potential for understanding the study of visual culture as a field that is interwoven with the assumptions of abductive cognition.

This is a conjecture about the conditions and operating structures that are required for the phenomenality of certain mental states. Specifically, full-blown phenomenality is assumed, as contrasted with constrained examples of phenomenal experience such as sensations of color and pain. Propositional attitudes and content, while not phenomenal per se, are standardly concurrent and may condition phenomenal states (e.g., when tied to false beliefs). It is conjectured that full phenomenality natively arises in coherent processes of situated sensory synthesis and representation (...) (with conceptual content) that are looped, mereologically whole and multi-dimensional. And that phenomenal states are typically phase-states within a parameterized conjoint structure of world and experiencer processes that are causally modulated across Markov blankets (which are conditionally independent and may be nested: cf. M. Kirchoff, et. al., 2017, 2018; and T. Burge, 2010, re: anti-individualism). Though they may, it is not accepted that phenomenally conscious states must be targets of higher-order representations (cf. A. Byrne, 2004). (shrink)

We survey the history of Shelah’s conjecture on strongly dependent fields, give an equivalent formulation in terms of a classification of strongly dependent fields and prove that the conjecture implies that every strongly dependent field has finite dp-rank.

We investigate how weak square principles are denied by Chang’s Conjecture and its generalizations. Among other things we prove that Chang’s Conjecture does not imply the failure of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\square_{\omega_1, 2}}$$\end{document}, i.e. Chang’s Conjecture is consistent with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\square_{\omega_1, 2}}$$\end{document}.

L’article fournit un exemple concret des possibilités qu’ouvre l’exploration des données numérisées, et notamment de la Toile, en matière de morphologie dérivationnelle. Il y a une soixantaine d’années, en se fondant sur un exemple unique (silvio-pelliqueste), Edouard Pichon avançait l’hypothèse qu’en contexte vélaire, le suffixe –esque pouvait, par un phénomène de dissimilation préventive, se voir remplacé par la finale –este. Depuis, aucun argument n’était venu étayer cette hypothèse, sinon peut-être des remarques hésitantes de Zwanenburg (1975) et de Björkman (1984) sur (...) la difficulté de trouver des dérivés en –esque après vélaire. Les données réunies confirment que l’adjonction de –esque à une base dont la dernière syllabe comporte une vélaire engendre des tensions dissimi-latives. Lorsque le contexte s’y prête, ces tensions se manifestent tantôt par l’effacement de certaines vélaires finales, tantôt par le maintien inattendu d’une voyelle finale précédée d’une vélaire. Elles se manifestent aussi, comme l’avaient entrevu nos prédécesseurs, par une moindre productivité de cette suffixation après les radicaux en vélaire. Dans l’établissement de ces résultats, l’utilisation d’un outil permettant de récupérer automatiquement sur la Toile des néologismes en fonction de leur terminaison, s’est révélée déterminante. Les recherches automatisées ont joué aussi un rôle capital quand il s’est agi de trouver des dérivés en ‑este et de montrer que ce suffixe n’était utilisé productivement qu’après vélaire, conformément à la conjecture de Pichon. (shrink)

L’article fournit un exemple concret des possibilités qu’ouvre l’exploration des données numérisées, et notamment de la Toile, en matière de morphologie dérivationnelle. Il y a une soixantaine d’années, en se fondant sur un exemple unique (silvio-pelliqueste), Edouard Pichon avançait l’hypothèse qu’en contexte vélaire, le suffixe –esque pouvait, par un phénomène de dissimilation préventive, se voir remplacé par la finale –este. Depuis, aucun argument n’était venu étayer cette hypothèse, sinon peut-être des remarques hésitantes de Zwanenburg (1975) et de Björkman (1984) sur (...) la difficulté de trouver des dérivés en –esque après vélaire. Les données réunies confirment que l’adjonction de –esque à une base dont la dernière syllabe comporte une vélaire engendre des tensions dissimi-latives. Lorsque le contexte s’y prête, ces tensions se manifestent tantôt par l’effacement de certaines vélaires finales, tantôt par le maintien inattendu d’une voyelle finale précédée d’une vélaire. Elles se manifestent aussi, comme l’avaient entrevu nos prédécesseurs, par une moindre productivité de cette suffixation après les radicaux en vélaire. Dans l’établissement de ces résultats, l’utilisation d’un outil permettant de récupérer automatiquement sur la Toile des néologismes en fonction de leur terminaison, s’est révélée déterminante. Les recherches automatisées ont joué aussi un rôle capital quand il s’est agi de trouver des dérivés en ‑este et de montrer que ce suffixe n’était utilisé productivement qu’après vélaire, conformément à la conjecture de Pichon. (shrink)

We prove that a combinatorial consequence of the negation of the PCF conjecture for intervals, involving free subsets relative to set mappings, is not implied by even the strongest known large cardinal axiom.