On the 25th anniversary of Berry’s historic papers on the geometric phase, I discuss here our neutron interferometry experiment in which this phase is clearly separated from the dynamical phase. The connection of this experiment to the observation of the sign reversal of the wave function of a fermion during a 2π precession in a magnetic field by three groups independently in 1975 is discussed.

This paper contributes to answering the question how physicalism can be defined for a world without fundamental physical phenomena. In a recent paper in this journal, Torin Alter, Sam Coleman, and Robert J. Howell propose a necessary condition on physicalism. They argue that physicalism is true only if there is no infinitely descending chain of mentally constituted phenomena. I argue that this alleged necessary condition faces counterexamples. An infinitely descending chain of mentally constituted phenomena is compatible with physicalism. Afterwards I (...) propose a simpler definition of physicalism that does not fall prey to my counterexample. (shrink)

A brief history of Neutron Interferometry is presented, from a personal perspective. Comments and a message from Professor Sam Werner are included.

Reverse mathematics is a program in the foundations of mathematics founded by Friedman and developed extensively by Simpson and others. The aim of RM is to find the minimal axioms needed to prove a theorem of ordinary, that is, non-set-theoretic, mathematics. As suggested by the title, this paper deals with two RM-phenomena, namely, splittings and disjunctions. As to splittings, there are some examples in RM of theorems A, B, C such that A↔, that is, A can be split into two (...) independent parts B and C. As to disjunctions, there are examples in RM of theorems D, E, F such that D↔, that is, D can be written as the disjunction of two independent parts E and F. By contrast, we show in this paper that there is a plethora of splittings and disjunctions in Kohlenbach’s higher-order RM. (shrink)

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Since Hegel, philosophy cannot stop thinking its end. The violent transformations which Hegel's philosophy has uncovered and caused in the structure of philosophical terms and in the terms under which philosophy is possible is Hamacher's topic. Starting from Hegel's commentaries on biblical scripture, Hamacher traces the genealogy and unfolding of Hegel's thought into his mature works--the Phenomenology of Spirit, the Encyclopedia, the Philosophy of History--focusing throughout on the limits and borders, the limitations and extremities of its conceptual and textual movements. (...) Because the concept for Hegel is the end of the thing--the point where it peaks--because it occurs by severance from its representational content, the trace of this splitting appears imprinted into its discursive articulation. The Hegelian text is punctuated by a series of terms and topics that operate according to the logic of the turning point: one function activating its opposite, they serve as pores between mutually exclusive experiences and establish their unity. This dialectical procedure falters, its unity dissolves, the pores turn into aporias, wherever conceptual exigencies surpass the reality they have instilled. Hamacher shows that dialectics, proceeding by way of aporias, remains unable to account for its own movement. Hegel's system must be read from the point where its rupture fails to converge with its end. Analyzing both the historical and the systematic aspects of Hegel's philosophy, addressing Kant and religious fetishism, Nietzsche and the impossible repetition of the same, Marx and the aroma of religion, Freud and the hysterical body, Hamacher's argument is directed toward what in Hegel's philosophy of spirit resists spiritualization and defeats philosophy. Aspiring to be the last philosophy, speculative idealism has to incorporate all previous systems and spiritualize its incorporation. Its logic of ingestion must, however, reject with repulsion and nausea everything that resists appropriation. Emphasizing Hegel's claim to present the political theology of modern society, Hamacher shows that the mechanism of nausea meant to keep the system intact is in fact itself a mechanism foreign to its body; it averts the promised incorporation, defeats idealization, leaves the body politic disintegrated, and voids the claim of the most powerful ontology of modern society to mark the end, the completion and plenitude--the pleroma--of philosophy and history. What remains--the indigestible, the unreadable, the nondiscursive--demands yet another kind of discourse and another practical gesture: toward a pleroma other than Hegel's. (shrink)

Since Hegel, philosophy cannot stop thinking its end. The violent transformation that Hegel's philosophy uncovered and caused in the structure of philosophical terms and in the terms under which philosophy is possible is Hamacher's topic. Starting from Hegel's commentaries on biblical scripture, Hamacher traces the genealogy and unfolding of Hegel's thought into his mature works - the Phenomenology of Spirit, the Encyclopedia, the Philosophy of History - focusing throughout on the limits and excesses of its conceptual and textual movements. Bacause (...) the concept for Hegel is the end of the thing - the point where it peaks - because it emerges by severing itself from its representational content, the discursive articulation of the concept bears the traces of this splitting. The Hegelian text is punctuated by a series of terms and topics that operate according to the logic of the turning point: every term releases its opposite, thus operating as pores between mutually exclusive experiences and establishing their unity. This dialectical procedure falters, its unity dissolves, the pores turn into aporias, wherever conceptual exigencies surpass the reality they have engendered. Hamacher shows that dialectics, proceeding by way of aporias, remains unable to account for its own movement. Hegel's system must be read from the point where its rupture fails to converge with its end. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Guilt History:Benjamin's Sketch "Capitalism as Religion"Werner Hamacher (bio)Translated by Kirk Wetters (bio)History as Exchange EconomySince history cannot be conceived as a chain of events produced by mechanical causation, it must be thought of as a connection between occurrences that meets at least two conditions: first that it admit indeterminacy and thus freedom, and second that it nonetheless be demonstrable in determinate occurrences and in the distinct form of (...) their coherence. Relations can thus be called historical and can be recognized as historical only if they are determined by neither necessity nor chance, and if their causality is of a different order than the mechanical. The temporal structure of history can therefore be characterized on the one hand by the distinct connection of its elements—and on the other hand by the dissolution of all connections that do not assist these elements in achieving their independence.A temporal nexus that clearly does not satisfy these conflicting requirements has been characterized in one of the oldest texts of occidental philosophy as the time of guilt. According to the sentence of Anaximander (from about 500 BC), handed down by Simplicius in his commentary (530 AD) on Aristotle's Physics, the origin and end of all things is subordinated to the law of necessity (katà tó kreòn). "They must pay penance and be judged for their injustice, according to the order of time (katà tèn tou chrónou táxin)"—so the fragment reads in the translation offered by Nietzsche in his treatise "Philosophy in the Tragic Age of the Greeks." According to Anaximander, the sequence of time orders the rise and fall of all things and orders them in accordance with the law of guilt and punishment so that becoming (génesis) is a guilt (adikía) that must be expiated in perishing. Time and more precisely its táxis, the positing of time, is thought in Anaximander's sentence as an order of guilt and retribution, debt and payback. It is a time of economy in the sense that it is the time of law—and precisely a law that is valid for all beings, a táxis, a decree, an ordinance and an ordering—in which the unavoidable incurring of guilt is atoned in an equivalent penance that is just as unavoidable. The strict coherence of guilt and penance is ascertained by the principle of their equivalence. Time is therefore conceived here as a double process of coming into being and perishing, [End Page 81] a process that occurs in such a way that the genesis is erased in its passing away—so that time is thus erased by time itself.In Anaximander's sentence, however, time is not only the double-process of coming into being and passing away, it is—as a táxis—the common and constantly enduring medium of the exchange of the contrary but equivalent motions of coming into being and perishing. It is the time of the quid pro quo of everything that is generated and passes away within time. Its measure is a justice that represents itself as a táxis and thereby as the positing and the law of all becoming and vanishing, the law of physis and its demise as an onto-economic law. This taxiological order of time places every realm of the natural and human world under a law of substitution without exception; this also allows ethical, juridical, and economic concepts to substitute for one another within this order. The ethical dimension of justice, thus circumscribed by the order of time, is reduced to the juridical dimension of the decree, and both now define themselves according to the calculus of "an exchange economy in an eternally unchanging household of nature."1 It can only, however, be a matter of an ethics of time to the extent that this ethics, already juridified and economized, is subordinated to the schema of exchange, trade, and the equivalence of guilt and retribution. The time of history, ethical time, is thus interpreted in Anaximander's sentence as a normative time of inculpation and expiation. Whatever enters this táxis of time is thereby already guilty and can... (shrink)

Definitive diagnosis of malaria requires the demonstration through laboratory tests of the presence within the patient of malaria parasites or their components. Since malaria parasites can be present even in the absence of malaria manifestations, and since symptoms of malaria can be manifested even in the absence of malaria parasites, malaria diagnosis raises important issues for the adequate understanding of disease, etiology and diagnosis. One approach to the resolution of these issues adopts a realist view, according to which the needed (...) clarifications will be derived from a careful representation of the entities on the side of the patient which form the ultimate truthmakers for clinical statements. We here address a challenge to this realist approach relating to the diagnosis of malaria, and show how this challenge can be resolved by appeal to Basic Formal Ontology (BFO) and to the Ontology for General Medical Science (OGMS) constructed in its terms. (shrink)

The question is, of whether alongside a theme and method concentrated philosophy teaching it would be sensisible for young people to have a teaching form where great philosophers themselves are the centre of interest and are presented as personalities engaged in philosophical research. As an illustration the philosophers Plato, René Descartes, John Locke and Immanuel Kant, who essentially laid down the foundations of modern scientific thinking, would be presented in relationship to teaching practice. This train of thought can be extended (...) without exception for all nations and all forms of culture so long as the conditions of peaceableness and civilizing productivity are met with. Exemplary biographies could play a large role for young people with regard to their psychological development. (shrink)

I discuss various reactions to my article “Again, what the philosophy of science is not” [Callebaut (Acta Biotheor 53:92–122 (2005a))], most of which concern the naturalism issue, the place of the philosophy of biology within philosophy of science and philosophy at large, and the proper tasks of the philosophy of biology.