Machery et al. presented data suggesting the existence of cross-cultural variation in judgments about the reference of proper names. In this paper, we examine a previously overlooked confound in the subsequent studies that attempt to replicate the results of Machery et al. using East Asian languages. Machery et al. and Sytsma et al. claim that they have successfully replicated the original finding with probes written in Chinese and Japanese, respectively. These studies, however, crucially rely on uses of articleless, ‘bare noun (...) phrases’ in Chinese and Japanese, which according to the linguistic literature are known to be multiply ambiguous. We argue that it becomes questionable whether the extant studies using East Asian languages revealed genuine cross-cultural variation when the probes are reevaluated based on a proper linguistic understanding of Chinese and Japanese bare noun phrases and English definite descriptions. We also present two experiments on native Japanese speakers that controlled the use of ambiguous bare noun phrases, the results of which suggest that the judgments of Japanese speakers concerning the reference of proper names may not diverge from those of English speakers. (shrink)

Gaisi Takeuti (1926–2017) is one of the most distinguished logicians in proof theory after Hilbert and Gentzen. He extensively extended Hilbert's program in the sense that he formulated Gentzen's sequent calculus, conjectured that cut-elimination holds for it (Takeuti's conjecture), and obtained several stunning results in the 1950–60s towards the solution of his conjecture. Though he has been known chiefly as a great mathematician, he wrote many papers in English and Japanese where he expressed his philosophical thoughts. In particular, (...) he used several keywords such as "active intuition" and "self-reflection" from Nishida's philosophy. In this paper, we aim to describe a general outline of our project to investigate Takeuti's philosophy of mathematics. In particular, after reviewing Takeuti's proof-theoretic results briefly, we describe some key elements in Takeuti's texts. By explaining these texts, we point out the connection between Takeuti's proof theory and Nishida's philosophy and explain the future goals of our project. (shrink)

Gaisi Takeuti extended Gentzen's work to higher-order case in 1950's–1960's and proved the consistency of impredicative subsystems of analysis. He has been chiefly known as a successor of Hilbert's school, but we pointed out in the previous paper that Takeuti's aimed to investigate the relationships between "minds" by carrying out his proof-theoretic project rather than proving the "reliability" of such impredicative subsystems of analysis. Moreover, as briefly explained there, his philosophical ideas can be traced back to Nishida's philosophy (...) in Kyoto's school. For the proving the consistency of such systems, it is crucial to prove the well-foundedness of ordinals called "ordinal diagrams" developed for it. Takeuti presented such arguments several times in order to show that they are admitted in his stand point. As a starting point of investigating his finitist stand point, we formulate the system of ordinal notations up to ε0 and reconstruct the well-foundedness arguments of them. (shrink)

Takeuti and Titani have introduced and investigated a logic they called intuitionistic fuzzy logic. This logic is characterized as the first-order Gödel logic based on the truth value set [0,1]. The logic is known to be axiomatizable, but no deduction system amenable to proof-theoretic, and hence, computational treatment, has been known. Such a system is presented here, based on previous work on hypersequent calculi for propositional Gödel logics by Avron. It is shown that the system is sound and complete, (...) and allows cut-elimination. A question by Takano regarding the eliminability of the Takeuti-Titani density rule is answered affirmatively. (shrink)

Boolean-valued models of set theory were independently introduced by Scott, Solovay and Vopěnka in 1965, offering a natural and rich alternative for describing forcing. The original method was adapted by Takeuti, Titani, Kozawa and Ozawa to lattice-valued models of set theory. After this, Löwe and Tarafder proposed a class of algebras based on a certain kind of implication which satisfy several axioms of ZF. From this class, they found a specific 3-valued model called PS3 which satisfies all the axioms (...) of ZF, and can be expanded with a paraconsistent negation *, thus obtaining a paraconsistent model of ZF. The logic (PS3 ,*) coincides (up to language) with da Costa and D'Ottaviano logic J3, a 3-valued paraconsistent logic that have been proposed independently in the literature by several authors and with different motivations such as CluNs, LFI1 and MPT. We propose in this paper a family of algebraic models of ZFC based on LPT0, another linguistic variant of J3 introduced by us in 2016. The semantics of LPT0, as well as of its first-order version QLPT0, is given by twist structures defined over Boolean agebras. From this, it is possible to adapt the standard Boolean-valued models of (classical) ZFC to twist-valued models of an expansion of ZFC by adding a paraconsistent negation. We argue that the implication operator of LPT0 is more suitable for a paraconsistent set theory than the implication of PS3, since it allows for genuinely inconsistent sets w such that [(w = w)] = 1/2 . This implication is not a 'reasonable implication' as defined by Löwe and Tarafder. This suggests that 'reasonable implication algebras' are just one way to define a paraconsistent set theory. Our twist-valued models are adapted to provide a class of twist-valued models for (PS3,*), thus generalizing Löwe and Tarafder result. It is shown that they are in fact models of ZFC (not only of ZF). (shrink)

The notion of equality between two observables will play many important roles in foundations of quantum theory. However, the standard probabilistic interpretation based on the conventional Born formula does not give the probability of equality between two arbitrary observables, since the Born formula gives the probability distribution only for a commuting family of observables. In this paper, quantum set theory developed by Takeuti and the present author is used to systematically extend the standard probabilistic interpretation of quantum theory to (...) define the probability of equality between two arbitrary observables in an arbitrary state. We apply this new interpretation to quantum measurement theory, and establish a logical basis for the difference between simultaneous measurability and simultaneous determinateness. (shrink)

This paper contributes to the debate regarding the semantic type of singular referential names. According to one view, known as referentialism, names rigidly designate individuals (Kripke 1972, Abbott 2002, Leckie 2013, Jeshion 2015, Schoubye 2017). According to another view, known as predicativism, names designate properties of individuals (Burge 1973, Geurts 1997, Bach 2002, Elbourne 2005, Matushansky 2008, Fara 2015). Most predicativist accounts claim that bare names in English occur with a phonologically null determiner, a proposal that is based on languages (...) like Greek where names require a determiner in argument position. Novel data from both English and Greek show that names can be nonrigid designators under modal operators ("Aristotle may teach Socrates") and bound variables under quantifiers ("in every set of twins, Helen is a musician"), challenging referentialism. As for rigidity, one possible source of this phenomenon is the proprial article, a name-specific determiner found in Catalan and other languages that may be null in English and homophonous with the definite article in Greek (Ghomeshi and Massam 2009, Muñoz 2019, Izumi and Erickson 2021). While much further research is needed, the data suggest that the proper analysis of names is grounded in predicativism rather than referentialism. (shrink)