The Einstein–Podolsky–Rosen paradox (1935) is reexamined in the light of Shannon’s information theory (1984). The EPR argument did not take into account that the observer’s information was localized, like any other physical object.

Bell inequalities are derived for any number of observers, any number of alternative setups for each one of them and any number of distinct outcomes for each experiment. It is shown that if a physical system consists of several distant subsystems, and if the results of tests performed on the latter are determined by local variables with objective values, then the joint probabilities for triggering any given set of distant detectors are convex combinations of a finite number of Boolean arrays, (...) whose components are either 0 or 1 according to a simple rule. This convexity property is both necessary and sufficient for the existence of local objective variables. It leads to a simple graphical method which produces a large number of generalized Clauser-Horne inequalities corresponding to the faces of a convex polytope. It is plausible that quantum systems whose density matrix has a positive partial transposition satisfy all these inequalities, and therefore are compatible with local objective variables, even if their quantum properties are essentially non-local. (shrink)

Popper conceived an experiment whose analysis led to a result that he deemed absurd. Popper wrote that his reasoning was based on the Copenhagen interpretation and therefore invalidated it. Many authors who have examined Popper's analysis have found in it various technical flaws which are briefly summarized here. However, the aim of the present article is not technical. My concern is to redress logical flaws in Popper's argument: the terminology he uses is ambiguous, his analysis involves counterfactual hypotheses, and it (...) violates Bohr's complementarity principle. Therefore, the absurdity of Popper's result only confirms Bohr's approach. (shrink)

The proof of Bell's inequality is based on the assumption that distant observers can freely and independently choose their experiments. As Bell's inequality isexperimentally violated, it appears that distant physical systems may behave as a single, nonlocal, indivisible entity. This apparent contradiction is resolved. It is shown that the “free will” assumption is, under usual circumstances, an excellent approximation.I have set before you life and death, blessing and cursing: therefore choose life.... —Deuteronomy XXX, 19.

This paper contains four new dialogues among Simplicio, Salviati, and Sagredo, on the fate of Schrödinger's cat, the existence of physical quantities, the paradigm of Einstein, Podolsky, and Rosen, and why a watched kettle may boil, after all.

Linear combinations of “elements of reality,” as defined by Einstein, Podolsky, and Rosen, may not be themselves “elements of reality.” There are questions which can be formulated (and unambiguously answered) in the ordinary language of experimental physics, but cannot be represented in the mathematical framework of quantum theory in a nontrivial way.

The purpose of this paper is to review and clarify the quantum “measurement problem.” The latter originates in the ambivalent nature of the “observer”: Although the observer is not described by the Schrödinger equation, it should nevertheless be possible to “quantize” him and include him in the wave function if quantum theory is universally valid. The problem is to prove that no contradiction may arise in these two conflicting descriptions. The proof invokes the notion of irreversibility. The validity of the (...) latter is questionable, because the standard rationale for classical irreversibility, namely mixing and coarse graining, does not apply to quantum theory. There is no chaos in a closed, finite quantum system. However, when a system is large enough, it cannot be perfectly isolated from its “environment,” namely from external (or even internal) degrees of freedom which are not fully accounted for in the Hamiltonian of that system. As a consequence, the long-range evolution of such a quantum system is essentially unpredictable. It follows that the notion of irreversibility is a valid one in quantum theory and the “measurement problem” can be brought to a satisfactory solution. (shrink)

An imprecise measurement of a dynamical variable (such as a spin component) does not, in general, give the value of another dynamical variable (such as a spin component along a slightly different direction). The result of the measurement cannot be interpreted as the value of any observable that has a classical analogue.

A generalized Kochen-Specker theorem is proved. It is shown that there exist sets of n projection operators, representing n yes-no questions about a quantum system, such that none of the 2″ possible answers is compatible with sum rules imposed by quantum mechanics. Namely, if a subset of commuting projection operators sums up to a matrix having only even or only odd eigenvalues, the number of “yes” answers ought to he even or odd, respectively. This requirement may lead to contradictions. An (...) example is provided, involving nine projection operators in a 4-dimensional space. (shrink)

The physicist not only observes phenomena, but he also has an active role in the formulation of some laws. For instance, laws involving irreversibility refer explicitly to what can or cannot be done by physicists. As the abilities of the latter may vary, we obtain sequences of laws, the convergence of which is discussed.

The city of lions. Beaulieu-sur-Dordogne. The war starts. Drôle de guerre. Going to work. Going to school. Fleeing from village to village. Playing cat and mouse. The second landing. Return to Beaulieu. Return to Paris. Joining the boyscouts. Learning languages. Israel becomes independent. Arrival in Haifa. Kalay high school. Military training. The Hebrew Technion in Haifa. Relativity. Asher Peres. Metallurgy. Return to France. Escape from jail. Aviva.I am the cat who walks by himself, and all places are alike (...) to me.Rudyard KiplingI am grateful to all those who contributed to this Festschrift which celebrates my 70th birthday and therefore the beginning of my eighth decade. In the Jewish religion, there is a prayer, “she-hehhyanu” to thank the Lord for having kept us alive and let us reach this day. I am an atheist and I have no Lord to thank, but I wish to thank many other people who are no longer alive and who helped me reach this point. (shrink)

A pair of spin-j particles, prepared in a singlet state, move away from each other and are examined by two distant observers. If the latter are able to discriminate between the2j+1 values of a component ofJ, there are pairs of observables whose correlation strongly violates Bell's inequality, for arbitrarily large j. However, if neighboring values are lumped together because of limited instrumental resolution, the observable correlations tend to those predicted by classical mechanics.

The most efficient way of obtaining information about the state of a quantum system is not always a direct measurement. It is sometimes preferable to extend the original Hilbert space of states into a larger space, and then to perform a quantum measurement in the enlarged space. Such an extension is always possible, by virtue of Neumark's theorem. The physical interpretation usually given to that theorem is the introduction of an auxiliary quantum system, prepared in a standard state, and the (...) execution of a quantum measurement on both systems together. However, this widespread interpretation is unacceptable, because the statistical properties of the supposedly standard auxiliary system are inseparably entangled with those of the original, unknown system. A different method of preparing the auxiliary system is proposed, and shown to be physically acceptable. (shrink)

“Elements of reality” are defined as in the work of Einstein, Podolsky, and Rosen. It is further assumed that the sum or product of twocommuting elements of reality also is an element of reality. An algebra contradiction ensues.

Preface for Festschrift for Asher Peres's 70th Birthday, Foundations of Physics, issues 35(11), 35(12), and 36(1). -/- “All my friends!” These were nearly the first words I ever heard come from Asher Peres’s mouth. It was at a conference in Maryland in 1994 honoring the 83rd birthday of John Wheeler. The first morning of the meeting I spied Asher walk out of the lecture hall and into a long hallway where, in the distance, he saw (...) a group of old colleagues. His words came out so spontaneously and so lovingly it left a mark on me. I thought, “What a wonderful way to lead a life!—to have results that effect the world over, to travel the world reporting them, to see each conference as a family reunion.” Asher was a man of family—his blood family in Israel and his family of physicist colleagues throughout the world. He nurtured all of us, and we are what we are in large part because of him. (shrink)

This volume is about abstract objects and the ways we refer to them in natural language. Asher develops a semantical and metaphysical analysis of these entities in two stages. The first reflects the rich ontology of abstract objects necessitated by the forms of language in which we think and speak. A second level of analysis maps the ontology of natural language metaphysics onto a sparser domain--a more systematic realm of abstract objects that are fully analyzed. This second level reflects (...) the commitments of real metaphysics. The models for these commitments assign truth conditions to natural language discourse. Annotation copyright by Book News, Inc., Portland, OR. (shrink)

The paper offers a new reading of the argument against poetry in Plato’s Republic 10. I argue that Socrates’ corruption charges rely on the tripartite theory of the soul, and that metaphysical doctrines play a role only in the first charge, which demonstrates that the poets are not qualified to teach by reducing tragic poetry to mimetic skill. This accusation clears the way for two corruption charges: the strengthening of appetite, and the softening of spirit (i.e., ‘the greatest charge’). The (...) former focuses on the dangerous association between the poets and the largest appetitive class in the city (hoi polloi), while the latter focuses on the corruption of the educated elite (hoi epieikeis). (shrink)

The study of the feeling of knowing may have implications for some of the metatheoretical issues concerning consciousness and control. Assuming a distinction between information-based and experience-based metacognitive judgments, it is argued that the sheer phenomenological experience of knowing (''noetic feeling'') occupies a unique role in mediating between implicit-automatic processes, on the one hand, and explicit-controlled processes, on the other. Rather than reflecting direct access to memory traces, noetic feelings are based on inferential heuristics that operate implicitly and unintentionally. Once (...) such heuristics give rise to a conscious feeling that feeling can then affect controlled action. Examination of the cues that affect noetic feelings suggest that not only do these feelings inform controlled action, but they are also informed by feedback from the outcome of that action. (shrink)

This is a book about the meanings of words and how they can combine to form larger meaningful units, as well as how they can fail to combine when the ...

I hope I have convinced the reader that DR theory offers at least some exciting potential when applied to the semantics of belief reports. It differs considerably from other approaches, and it makes intuitively acceptable predictions that other theories do not. The theory also provides a novel approach to the semantics of other propsitional attitude reports. Further, DR theory enables one to approach the topic of anaphora within belief and other propositional attitude contexts in a novel way, thus combining the (...) semantics developed here with one of the theory's original motivations (Kamp, 1981a). However, these are unfortunately topics that I must reserve for another time. (shrink)

“Metapolitics” is an ambiguous term. Recent philosophers have claimed the concept for neo-conservative, even right-wing agendas, while others have employed it to signal radical discontent with politics altogether. Beginning with Peter Viereck’s characterization of Nazi ideology as “Meta-Politics,” this essay works its way back from an “irrational,” “volkish,” and supposedly “conservative” concept to another use of “Metapolitics” as found in Martin Buber and Hermann Cohen that was rooted in a liberal tradition of the Enlightenment—especially in August Schlözer and Saul Ascher. (...) Both, Buber and Cohen, linked “metapolitical politics” to prophetic and theopolitical sensibilities. As such, the prophetic motif of turning loomed large at the center of their respective philosophies of nationalism. But it was a theme that also connected a wide range of thinkers, including Hans Kohn and Leo Baeck, and which emerged as a Leitmotiv of cultural and spiritual Zionism as well as of the modern Renaissance of Jewish culture. Drawing on Moritz Lazarus, the essay argues that the recurring trope of turning helped establish a paradoxical nationalism founded not upon self-empowerment and political othering but on self-criticism. Concluding with a brief excursion on Abraham Joshua Heschel’s prophetic politics in the Civil Rights Movement, the essay gestures towards the possibility of nationalism as collective introspection and self-reformation. (shrink)

CRISPR-Cas9 genome editing can and has altered human genomes, bringing bioethical debates about this capability to the forefront of philosophical and policy considerations. Here, I consider the underexplored implications of CRISPR-Cas9 gene drives for heritable human genome editing. Modification gene drives applied to heritable human genome editing would introduce a novel form of involuntary eugenic practice that I term guerrilla eugenics. Once introduced into a genome, stealth genetic editing by a gene drive genetic element would occur each subsequent generation irrespective (...) of whether reproductive partners consent to it and irrespective of whether the genetic change confers any benefit. By overriding the ability to ‘opt in’ to genome editing, gene drives compromise the autonomy of carrier individuals and their reproductive partners to choose to use or avoid genome editing and impose additional burdens on those who hope to ‘opt out’ of further genome editing. High incidence of an initially rare gene drive in small human communities could occur within 200 years, with evolutionary fixation globally in a timeframe that is thousands of times sooner than achievable by non-drive germline editing. Following any introduction of heritable gene drives into human genomes, practices intended for surveillance or reversal also create fundamental ethical problems. Current policy guidelines do not comment explicitly on gene drives in humans. These considerations motivate an explicit moratorium as being warranted on gene drive development in heritable human genome editing. (shrink)

Franz Rosenzweig’s Star of Redemption culminates in an aesthetic configuration of simultaneous presences: world, man, God, creation, revelation, and redemption are viewed in a metahistorical side-by-side, connected by the “factualizing power of the And.” But the idea of simultaneity, which is central to Rosenzweig’s configurative thinking, belongs to the historical imagination as much as it belongs to the theological “breaking through the shackles of time.” Rosenzweig’s “and” belongs to both a tradition of cosmic-aesthetic historicism and the philosophical reconstitution of time (...) as a simultaneous perception. In the co-presence of all historical moments, history’s hidden Gestalt, which only a people that is at once old and young can envision, connects the “and” of history with what Hegel considered history’s end—its ultimate self-recognition. Eternity, then, means neither flight from, nor resistance to, history’s naked fact, but the recognition of history’s Gestalt as an image that “does not tolerate epochs.”. (shrink)

Fundamentismus und Skeptizismus-Anarchismus sind zwei entgegengesetzte Positionen in der traditionellen Erkenntnistheorie und in der modernen Wissenschaftstheorie. Zwischen ihnen gibt es einen dritten Standpunkt, den Evolutionismus. Beispiele sind zwei neuere Arbeiten von Putnam und Stegmüller . Im Gegensatz zum logisch-statischen Fundamentismus berücksichtigt der Evolutionismus auch dynamische und naturalistische Ansätze. Stegmüller folgend entlehnen wir in der vorliegenden Untersuchung aus der Sprachphilosophie pragmatische Gesichtspunkte, um die logische Syntax und Semantik, die Werkzeuge des Fundamentismus, zu ersetzen. Wir zeigen die Kraft der Pragmatik bei der (...) Behandlung von Problemen wie Erkenntniswachstum, Begriffswechsel, Theorien- und Bedeutungsdynamik, wissenschaftliche Entdeckung und besonders beim Problem der Inkommensurabilität. Unser nicht-fundamentistischer Vorschlag ist ein heuristisches Modell, das auf der modernen genetischen Theorie basiert. (shrink)

Recent research has filled many gaps about Caenorhabditis natural history, simultaneously exposing how much remains to be discovered. This awareness now provides means of connecting ecological and evolutionary theory with diverse biological patterns within and among species in terms of adaptation, sexual selection, breeding systems, speciation, and other phenomena. Moreover, the heralded laboratory tractability of C. elegans, and Caenorhabditis species generally, provides a powerful case study for experimental hypothesis testing about evolutionary and ecological processes to levels of detail unparalleled by (...) most study systems. Here, I synthesize pertinent theory with what we know and suspect about Caenorhabditis natural history for salient features of biodiversity, phenotypes, population dynamics, and interactions within and between species. I identify topics of pressing concern to advance Caenorhabditis biology and to study general evolutionary processes, including the key opportunities to tackle problems in dispersal dynamics, competition, and the dimensionality of niche space. (shrink)