Blockchain Papers

STEFANO CAROTI

Orazio Ricasoli Rucellai is one of the leading eruditi of the second half of 17th-century Florence; he tried to keep alive Galileo’s contribution to science. Most of his Dialoghi filosofici have been published at the end of 19th century; among the unpublished dialogues dedicated to Timaeus we find a partial defence of Descartes’ metaphysics, which is edited in the Appendix. In particular, the topics at stake are the demonstration of God’s existence and of the immateriality of the soul in Descartes’s Meditationes. The opponent of Descartes’s doctrine relies on Gassendi’s Obiectiones. Descartes’s doctrine of ideas completely detached from sense perception is dismissed as useless on a cognitive basis, and only a generic innatism is maintained, only as far as it can provide a proof of God’s imprint on human soul.

Vojtěch Sadil

The paper is aimed at a very accurate topic which is problematic of cryptocurrency Bitcoin. The main aim of this paper is to evaluate the potential of this most important cryptocurrency to serve as full-value money. The matter of the first chapter is introducing the Bitcoin concept including its characters and history. In this phase, we are thinking about Bitcoin as a commodity. The analysis of cryptocurrency Bitcoin within currency relations framework is subject for next chapter. Each commodity, which has a role of money, must fulfil three criteria. This commodity must be convertible, relative stable and liquid. This paper discusses the evaluation of these aspects. Based on the analysis, we can contribute to the question whether bitcoin can be used as full-value money in the future. The paper is not concerned on technical aspects like the algorithm of mining, blockchain technology or account safety.

Daniel M. Gross

Reviews 209 Jamie Dow, Passions & Persuasion in Aristotle's Rhetoric (Oxford University Press) Oxford & New York, 2015. 248 pp. ISBN9780198716266 Aristotle s Rhetoric has long posed problems of fit, which makes its uptake particularly revealing of the preoccupations that define a historical moment. Where should the Rhetoric be situated in the Corpus Aristotelicuml Is it primarily a practical work in the handbook tradition, or is it supposed to offer a full-blown theory of rhetoric? Should it be approached as a kind of philosophy, or something else entirely, especially since it devotes so much attention to style and passion? Is it even a coherent text to begin with? In his ambitious book, Passions & Persuasion in Aristotle's Rhetoric, Jamie Dow begins with these basic questions in mind, and he defends a set of interlocking answers that point to the Rhetoric as a serious, philosophical work along the following lines. Aristotle's Rhetoric is primarily a work on argumentation as understood by medieval Arab commentators along with some of our contemporaries including Bumyeat and Allen; it offers a full­ blown theory of rhetoric opposed to the handbook tradition of Gorgias and Thrasymachus; it is coherent in general and in detail, and it legitimates on philosophical grounds the use of passion in rhetoric. Thus, Dow's project also speaks to our historical moment—broadly postwar—when passions in political life became suspect for good reasons. Few will agree with all of the key claims as laid out by Dow or with each of the demonstrations offered. But it is an outstanding virtue of the book that Dow defends each claim with such care that even objections can be sharpened productively. In what follows, I outline the main arguments and what appears to be at stake. The first page offers the basic argument and a sense of the imperatives that make Dow's book bracing. "The principal claim defended in this book is that, for Aristotle in the Rhetoric, arousing the passions of others can amount to giving them proper grounds for conviction, and hence a skill in doing so is properly part of an expertise in rhetoric. This claim rests on two principal foundations. First, it involves defending the attribution to Aristotle of a norma­ tive view of rhetoric, centered around its role in the state, in which rhetoric is a skill producing proper grounds for conviction. If the arousal of the passions is part of rhetoric, thus understood, Aristotle must hold, second, a particular view of the passions: he must think they are representational states, in which the subject takes things to be the way they are represented" (p. 1). First Foundation I: this normative view, according to Dow, contrasts sharply with the merely practical understanding of rhetoric held by his pre­ decessors in the handbook tradition, and it diverges from the Platonic expectation that the orator needs to know the truth about the subject matter. Instead, according to Dow, Aristotle's orator should skillfully grasp plausi­ ble starting points for the listener's deliberations in the form of reputable opinions" (endoxa) related to the subject at hand (pp- 34—5). So how exactly is the rhetor obligated, and why isn't this obligation arbitrary? Here Dow is careful not to invoke some higher ethical principle. The obligation of the 210 RHETORICA rhetor remains immanent to the skill itself, as it becomes manifest in the context of the state organized along participatory lines. That is to say, rhetoric is by virtue of the world in which it appears as such—originally in the lawcourts and in the political assembly (p. 9). Understood at the most basic level, a rhetor should exercise skill precisely where the subject at hand speaks to the commonplaces and reputable opinions anchored in the state thus consti­ tuted. This is an important point that Dow wishes to extend beyond Aristotle per se: rhetorical skill has wide value and it must be measured as such (p. 76). Hence Dow gives us an ethos-proof like this: "they believe the things Pericles has said, because they believe Pericles—he himself is what is pistos" (p. 98). And then more formally this example of a pathos-proof: "1.1 register evidence...

Sébastien Gandon, Brice Halimi

All the articles of this issue come from the international conference ‘Logicism Today’ organized in Besse-en-Chandesse (the very place where the first Bourbaki Congress was held) in June 2011.1 The wish of the organizers was to explore the internal diversity of the logicist movement, and to delineate its coherence and conceptual core: is there something, beyond the allegiance to the same forefathers, Frege, Russell and Carnap, and beyond confronting common adversaries, which would constitute a shared conceptual framework? Or, on the contrary, should one give up trying to find conceptual unity in what is really an archipelago of different programs? This was a risky undertaking since it looked very much like a family meeting, where one's dirty linen can be washed in private. Happily, this did not happen, and we warmly thank Patricia Blanchette, Valentin Sorin Costreie, Bob Hale, Gregory Landini, Øystein Linnebo, Steven Methven, Marco Panza, Robert Trueman, Sean Walsh, Mark Wilson, and all the students attending the talks for having always preferred constructive criticisms to lazy dismissings. What emerged finally was the multiform implementation of logicism according to three main parameters: the founding father taken as a reference (Frege, Russell, Ramsey, …), the connection established between logicism and philosophy of mathematics, the connection established between logicism and philosophy of language. The papers collected in this issue give a fair picture of the diversity of all talks. The first two, Hale's and Wilson's, pertain to properties, extensions, and sets. The last three get back to Russell, Landini's to clarify the lesson usually learned from Russell's paradox, Gandon's and Halimi's to focus on Russell's substitutional theory. Despite its multifarious aspects, logicism always corresponds to some balance sought between speculative constraints (concerning the use of unrestricted variables, the rejection of ontological types, or the status of properties) and mathematical goals (the abstractionist reconstruction of mathematical objects, the logical analysis of mathematical theories, the conceptual grasp of mathematical-physical processes). In ‘Properties and the interpretation of second-order logic’, Bob Hale offers a fresh look at the neo-Fregean abstractionist program in philosophy of mathematics through a discussion of the second-order comprehension scheme and an analysis of the very nature of the properties that are quantified over in that scheme. Hale's paper defends a deflationary approach where a property exists if and only if there stands for it a predicate that can be given appropriately determinate satisfaction conditions. Accordingly, it puts forward a nonstandard semantics for second-order logic, where the range of monadic second-order variables is the collection of all the subsets of the individual domain that are definable in the metalanguage. By doing so, he departs from Frege on two scores: first because he endorses an intensional view of properties and defines identity of two properties through a modal clause; secondly, because he does not take second-order quantification to be unrestricted. Above all, the main thread of the paper is a metaphysical analysis of properties whose consequences for logic and mathematics are only derivative. Hale concludes his analysis with two points: the first is that the usual metalogical features of compactness and completeness still hold in his semantical framework; the second is that categoricity of second-order axiomatization of important mathematical theories fails but can be given up without great loss. Hale finally focuses on the issue of impredicativity of second-order comprehension and argues both that his conception refers to a determinate range of possible values and that it is not inflationary. In ‘Enlarging one's stall or How did all of these sets get in here?’, Mark Wilson claims that two very different reasons led mathematicians to introduce sets in their theories. Set theory was first needed to extend the use of our concepts, ‘to shore up the so-called “free creativity of the mathematician” ’. Foundational programs based on abstraction principles still follow this old path. According to Wilson, however, another fundamental, yet often neglected, rationale has to be recognized behind the introduction of sets, namely ‘the desirability of understanding our computational relationships to the sorts of physical behaviors captured in differential equations (and allied forms of dynamical recipe)’. Wilson takes and deepens several examples of functions introduced by differential equations: the recourse to sets has to be understood in the context of the ‘algorithmic adjustments’ needed to extract reliable information from the equation and to compute as accurately as possible the solutions of the function at stake. Now, the language of set theory has proved to be the most natural to capture ‘our computational place in nature’, i.e., to describe the ‘mildly transcendental circumstances’ under which our ever-improving computations surround some target curve, asymptotically home in on natural processes or, on the contrary, fail to converge to the actual solution. Wilson then underlines that physical structures cannot generally be described as structures for a formal language, because the most important physical features of reality cannot be reduced to a list of primitive predicates. Set theory enters the scene precisely to capture previously unconceptualized properties, i.e., to handle physically relevant quantities to which no available linguistic predicate corresponds. The rest of Wilson's paper turns toward the other motivation for set theory, but illustrates the role of sets as supplementary entities by concrete detailed examples that point once again to geometry and mathematical physics. Wilson's conclusion is that hostility toward sets as abstract objects stems only from the stress put on one aspect of sets at the expense of the other, and from a philosophical blindness to the computational involvement of sets. Which is all grist for the partisan of mathematical naturalism. In ‘Zermelo and Russell's paradox’, Gregory Landini sets out to defuse Zermelo's priority claim, according to which Zermelo would have discovered, before Russell, what has become to be known as Russell's paradox. Through a careful examination of Zermelo's unpublished 1899 proof, Landini argues that Zermelo's result does not amount to Russell's paradox and does not show that there is no universal set: whereas Zermelo presupposed the full truth of the axiom of separation in order to prove that there is no universal set, Russell considered on the contrary the existence of a universal set as granted and diagnosed a ‘very subtle fallacy’ in the proof of Cantor's powerset theorem, due to the falsity of one instance of the axiom of separation. Indeed, as a consequence of a purely logical theorem proved by Russell in 1905 in ‘On some difficulties in the theory of transfinite ordinals and order types’, the introduction of the diagonal set corresponding to the universal set has to be precluded. Of course, Cantor's powerset theorem is true in modern set theory (with the axiom of separation available), but admission of set theory just begs the question. It remains that Zermelo's argument may be construed as a refutation, at least, of the extensional conception of sets (according to which any set is the extension of some propositional function, and any extension, a set). Yet the full refutation of the extensional conception, and the genuine Russell's paradox as well, only come from the Appendix B of the Principles of Mathematics: in short, Russell is the sole genuine author of Russell's paradox. In ‘Variable, structure and restricted generality’ and ‘Structured variables’, Sébastien Gandon and Brice Halimi draw on Russell's 1906 substitutional theory to reflect on generality and variables. Owing to Russell's universalism (his view that variables are ultimately unrestricted), the main problem is how to get a genuinely restricted range of variation. Gandon argues that structuring the variables is the Russellian answer. He goes on to cast a new light on the Julius Caesar problem and on the problem of absolute generality. Russell's substitutional approach, indeed, helps to explain why ‘2 is Julius Caesar’ is meaningless while avoiding any type distinction. It also gives rise to an ‘absolutely restricted generality’, i.e., restricted ranges of significance structurally emerging from within an absolute understanding of everything — whereas Tarski's semantics leans on relatively unrestricted domains (each domain representing a relative interpretation of ‘everything’). In connection with that point, Halimi uses the framework of syntactic fibrations as a platform to compare and partly conciliate Russell's and Tarski's respective conceptions of what it is to be a possible value for a variable. The aim pursued is first to reactivate Russell's substitutional insight in a fibrational setting. It is also to relativize Tarski's semantics as a degenerate case of what can be introduced as ‘Tarski's fibration’, namely the environment obtained when all assignments of values for variables of some language are not considered in one structure at a time, but taken upon the base space of all structures for the language. In Russell's as in Tarski's fibration, the structure of structured variables comes from the constraints set upon all the ways of picking out an item in each fiber. In other words, logical structure is construed as what restricts the available sections of some given logical fibration. The tool of fibrations, coming from category theory, thus allows one to put to the fore variables that are both structured as in Russell and interpreted as in Tarski.

Tom Conley

Reviewed by: Heuretics: The Logic of Invention Tom Conley Heuretics: The Logic of Invention, by Gregory L. Ulmer; xiv & 267 pp. Baltimore: Johns Hopkins University Press, 1994, $40.00 cloth, $13.95 paper. Heuretics designates areas of logic devoted to discovery and invention. This book sets out to reconfigure the metaphors that have dominated investigation since the advent of print-culture and the Columbian voyages. Adventure, quest, risk, discovery: Francis Bacon’s analogy of scientific research to oceanic travel established the stereotypes that Ulmer strives to dismantle. In 1962 Claude Lévi-Strauss noted in The Raw and the Cooked that in our time: “It is no longer a question of sailing toward other lands: only the voyage is real, not the earth, and the routes have been replaced by the rules of navigation.” With the advent of hypermedia, creation becomes an art of selection and combination. Truth gives way to discovery. Creation is likened to a programmed mélange of material ordered by negotiation, intuition, and strategy. Ulmer performs his proof—and proves his performance—by constructing a virtual staging of a multilayered commemoration he fashions from cinema, architecture, Jacques Derrida’s oeuvre, American history, and autobiography. The result is a collage of signifiers that apposes literary theory, memory-arts, Gary Cooper’s persona in Beau Geste (dir. William Wellman, 1939), Columbian voyages, Platonic dialogues, and a canon of postmodern writings. Ulmer divides the book into four parts, the first of which crafts the overall method from Cartesian reason and Surrealist practices of juxtaposition and automatism. Part two offers a dynamic definition of choreography, the study of local, inherited, and originary areas in which subjectivity is born. In part three Ulmer [End Page 147] sets forth textual rehearsals, based on Lee Strasner’s Method (via Stanislavsky), that mobilize the space and time of his chosen materials. Part four, “Yellowstone Desert,” bring together the strands of the narrative embroidery into a gag-joke (a “puncept” on Custer and custard) that explodes in the author’s face. A good deal of the work turns on Ulmer’s treatment of chora. Exploiting its signifying potential (chora, corps, choral, chorus, coral) he discovers that the myth of the world’s creation recounted in the Timaeus begins when the demiurge makes an X from two strands of plasma. The chi is folded as colures of a sphere that becomes the globe. Nonetheless the presence of the self as an unknown (x) is inferred (in I, or ich). Ulmer shows that “in subordinating mystery to memory, and arguments to paradigms,” choreography will “engage the users’ premises in the process of learning, opening a mutually transforming circuit between judgment and theory, and hence affect not only (. . .) institutional practices (. . .) but human subjectivation as well” (p. 202). Patterned constructions replace the creation and resolution of enigmas. Hypermedia becomes the technology of new creation, while choreography comprises “the institutional practice for augmenting the intuitions of inference, for writing with the logic of the unconscious” (p. 224). Heuretics extends the field of play staked out in Ulmer’s Teletheory. Here is offered a scheme for creating multileveled texts that are both creative and critical and infinitely generative, and that invite readers to connect electronic media to the unconscious. Most readers will not fail to appreciate the wit of the exposition and the clarity of the creative method. Others will pause over some of its assumptions. Certain critical paradigms, such as the antithetical ontologies of Lacan and Derrida, appear easily reconciled. The unnameable traumas of history (genocide) and psychogenesis (the birth and growth of subjectivity) are glossed with an effortless art of citation (pp. 114, 233). The unconscious is assimilated into an easily “accessed” logic, the latter effortlessly “logging in” to the former. The redesign of the Columbian quincentenary indirectly ratifies some of the modes of control that flexible capitalism seeks to impose upon the unconscious. These four points require greater space of exchange in the rich and problematic dialogue that informs Ulmer’s stunning performance of theory. Tom Conley University of Minnesota Copyright © 1995 The Johns Hopkins University Press