It has been suggested that difficult-to-quantify differences in visual processing may prevent researchers from equating the color experience of different observers. However, spectral locations of unique hues are remarkably invariant with respect to everything other than gross differences in preretinal and photoreceptor absorptions. This suggests a stereotyping of neural color processing and leads us to posit that minor differences in observer neurophysiology may be irrelevant to color experience.

Theoretical equivalence and duality are two closely related notions: but their interconnection has so far not been well understood. In this paper I explicate the contribution of a recent schema for duality to discussions of theoretical equivalence. I argue that duality suggests a construal of theoretical equivalence in the physical sciences. The construal is in terms of the isomorphism of models, as defined by the schema. This construal gives interpretative constraints that should be useful for discussions of (...) theoretical equivalence more generally. I illustrate the construal in various formulations of Maxwell’s electromagnetic theory. (shrink)

Change and local spatial variation are missing in canonical General Relativity's observables as usually defined, an aspect of the problem of time. Definitions can be tested using equivalent formulations of a theory, non-gauge and gauge, because they must have equivalent observables and everything is observable in the non-gauge formulation. Taking an observable from the non-gauge formulation and finding the equivalent in the gauge formulation, one requires that the equivalent be an observable, thus constraining definitions. For massive photons, the de Broglie-Proca (...) non-gauge formulation observable A_{\mu} is equivalent to the Stueckelberg-Utiyama gauge formulation quantity A_{\mu} + \partial_{\mu} \phi, which must therefore be an observable. To achieve that result, observables must have 0 Poisson bracket not with each first-class constraint, but with the Rosenfeld-Anderson-Bergmann-Castellani gauge generator G, a tuned sum of first-class constraints, in accord with the Pons-Salisbury-Sundermeyer definition of observables. The definition for external gauge symmetries can be tested using massive gravity, where one can install gauge freedom by parametrization with clock fields X^A. The non-gauge observable g^{\mu\nu} has the gauge equivalent X^A,_{\mu} g^{\mu\nu} X^B,_{\nu}. The Poisson bracket of X^A,_{\mu} g^{\mu\nu} X^B,_{\nu} with G turns out to be not 0 but a Lie derivative. This non-zero Poisson bracket refines and systematizes Kuchař's proposal to relax the 0 Poisson bracket condition with the Hamiltonian constraint. Thus observables need covariance, not invariance, in relation to external gauge symmetries. The Lagrangian and Hamiltonian for massive gravity are those of General Relativity + \Lambda + 4 scalars, so the same definition of observables applies to General Relativity. Local fields such as g_{\mu\nu} are observables. Thus observables change. Requiring equivalent observables for equivalent theories also recovers Hamiltonian-Lagrangian equivalence. (shrink)

Change and local spatial variation are missing in Hamiltonian general relativity according to the most common definition of observables as having 0 Poisson bracket with all first-class constraints. But other definitions of observables have been proposed. In pursuit of Hamiltonian–Lagrangian equivalence, Pons, Salisbury and Sundermeyer use the Anderson–Bergmann–Castellani gauge generator G, a tuned sum of first-class constraints. Kuchař waived the 0 Poisson bracket condition for the Hamiltonian constraint to achieve changing observables. A systematic combination of the two reforms (...) might use the gauge generator but permit non-zero Lie derivative Poisson brackets for the external gauge symmetry of General Relativity. Fortunately one can test definitions of observables by calculation using two formulations of a theory, one without gauge freedom and one with gauge freedom. The formulations, being empirically equivalent, must have equivalent observables. For de Broglie-Proca non-gauge massive electromagnetism, all constraints are second-class, so everything is observable. Demanding equivalent observables from gauge Stueckelberg–Utiyama electromagnetism, one finds that the usual definition fails while the Pons–Salisbury–Sundermeyer definition with G succeeds. This definition does not readily yield change in GR, however. Should GR’s external gauge freedom of general relativity share with internal gauge symmetries the 0 Poisson bracket, or is covariance sufficient? A graviton mass breaks the gauge symmetry, but it can be restored by parametrization with clock fields. By requiring equivalent observables, one can test whether observables should have 0 or the Lie derivative as the Poisson bracket with the gauge generator G. The latter definition is vindicated by calculation. While this conclusion has been reported previously, here the calculation is given in some detail. (shrink)

This paper contributes to our formal understanding of the common law — especially the nature of the reasoning involved, but also its point, or justification, in terms of social coordination. I present two apparently distinct models of constraint by precedent in the common law, establish their equivalence, and argue for a perspective according to which courts are best thought of, not as creating and modifying rules, but as generating a social priority ordering on reasons through a procedure that (...) is piecemeal, distributed, and responsive to particular circumstances. (shrink)

Einstein considered general covariance to characterize the novelty of his General Theory of Relativity (GTR), but Kretschmann thought it merely a formal feature that any theory could have. The claim that GTR is ``already parametrized'' suggests analyzing substantive general covariance as formal general covariance achieved without hiding preferred coordinates as scalar ``clock fields,'' much as Einstein construed general covariance as the lack of preferred coordinates. Physicists often install gauge symmetries artificially with additional fields, as in the transition from Proca's to (...) Stueckelberg's electromagnetism. Some post-positivist philosophers, due to realist sympathies, are committed to judging Stueckelberg's electromagnetism distinct from and inferior to Proca's. By contrast, physicists identify them, the differences being gauge-dependent and hence unreal. It is often useful to install gauge freedom in theories with broken gauge symmetries (second-class constraints) using a modified Batalin-Fradkin-Tyutin (BFT) procedure. Massive GTR, for which parametrization and a Lagrangian BFT-like procedure appear to coincide, mimics GTR's general covariance apart from telltale clock fields. A generalized procedure for installing artificial gauge freedom subsumes parametrization and BFT, while being more Lagrangian-friendly than BFT, leaving any primary constraints unchanged and using a non-BFT boundary condition. Artificial gauge freedom licenses a generalized Kretschmann objection. However, features of paradigm cases of artificial gauge freedom might help to demonstrate a principled distinction between substantive and merely formal gauge symmetry. (shrink)

The author considers James’ (1910) essay The Moral Equivalent of War and applies some of its ideas to another pressing problem of our times, which for short is called greed, but can be described more precisely as the working out of the possessive market society under the conditions of neoliberalism and great technological power. James considered that pacifists had the best arguments, but failed to persuade mainstream society. The same can be said today of the critics of neoliberalism. There is (...) need for radical change away from an unjust and dysfunctional economic system, but mainstream society is unwilling to try new ideas. The present author adapts James’ idea and considers benign and malign forms of greed. What we all desire, more than huge monetary assets, is self-respect and social respect. There are already many rewards that are not primarily monetary. In a radically different culture, which rejected the principles of unlimited accumulation and almost unlimited convertibility, benign rewards would motivate constructive activity. The moral equivalents of greed briefly discussed here are—Honours and prizes for merit (administered justly); Celebrity (important in society); Luck (gambling, with certain constraints, could be benign); Power (rewarding in itself, so large monetary gain need not go with it); Services (people making important contributions to society could concentrate their commitment); Temporary custody of public treasures (a privilege prized by some). The essay ends by linking James’ idea, the Faustian bargain myth, and the necessity of hope. (shrink)

In Dirac-Bergmann constrained dynamics, a first-class constraint typically does not _alone_ generate a gauge transformation. By direct calculation it is found that each first-class constraint in Maxwell's theory generates a change in the electric field E by an arbitrary gradient, spoiling Gauss's law. The secondary first-class constraint p^i,_i=0 still holds, but being a function of derivatives of momenta, it is not directly about E. Only a special combination of the two first-class constraints, the Anderson-Bergmann -Castellani gauge generator (...) G, leaves E unchanged. This problem is avoided if one uses a first-class constraint as the generator of a _canonical transformation_; but that partly strips the canonical coordinates of physical meaning as electromagnetic potentials and makes the electric field depend on the smearing function, bad behavior illustrating the wisdom of the Anderson-Bergmann Lagrangian orientation of interesting canonical transformations. The need to keep gauge-invariant the relation dot{q}- dH/dp= -E_i -p^i=0 supports using the primary Hamiltonian rather than the extended Hamiltonian. The results extend the Lagrangian-oriented reforms of Castellani, Sugano, Pons, Salisbury, Shepley, _etc._ by showing the inequivalence of the extended Hamiltonian to the primary Hamiltonian even for _observables_, properly construed in the sense implying empirical equivalence. Dirac and others have noticed the arbitrary velocities multiplying the primary constraints outside the canonical Hamiltonian while apparently overlooking the corresponding arbitrary coordinates multiplying the secondary constraints _inside_ the canonical Hamiltonian, and so wrongly ascribed the gauge quality to the primaries alone, not the primary-secondary team G. Hence the Dirac conjecture about secondary first-class constraints rests upon a false presupposition. The usual concept of Dirac observables should also be modified to employ the gauge generator G, not the first-class constraints separately, so that the Hamiltonian observables become equivalent to the Lagrangian ones such as the electromagnetic field F. (shrink)

ABSTRACTAccording to the prioritized reason model of precedent, precedential constraint is explained in terms of the need for decision-makers to reconcile their decisions with a settled priority order extracted from past cases. The prioritized reason model of precedent departs from the view that common law rules comprise protected reasons for action. In this article I show that a model utilizing protected reasons and the prioritized reason model of precedential constraint are, in an important sense, equivalent. I then offer (...) some reflections on the philosophical significance of this result. I argue that the protected reason model is consistent with the phenomenology of precedential constraint. I suggest an account of precedential reasoning that reconciles the prioritized reason and protected reason models. (shrink)

The night-watchman state of classical liberal theory, limited to the functions of protecting all its citizens against violence, theft, and fraud, and to the enforcement of contracts, and so on, appears to be redistributive.1 We can imagine at least one social arrangement intermediate between the scheme of private protective associations and the night-watchman state. Since the nightwatchman state is often called a minimal state, we shall call this other arrangement the ultraminimal state. An ultraminimal state maintains a monopoly over all (...) use of force except that necessary in immediate selfdefence, and so excludes private (or agency) retaliation for wrong and exaction of compensation; but it provides protection and enforcement services only to those who purchase its protection and enforcement policie., People who don't buy a protection contract from the monopoly don't get protected. The minimal (night-watchman) state is equivalent to the ultraminimal state conjoined with a (clearly redistributive) Friedmanesque voucher plan, financed from tax revenues.2 Under this plan all people, or some (for example, those in need), are given tax-funded vouchers that can be used only for their purchase of a protection policy from the ultraminimal state. (shrink)

Learning equivalence classes of acyclic models with latent and selection variables from multiple datasets with overlapping variables is discussed. The problem of inferring the presence of latent variables, their relation to the observables, and the relation among themselves, is considered. A different approach for identifying causal structures, one that results in much simpler equivalence classes, is provided. It is found that the computational cost is much higher than the procedure implemented, but if datasets are individually of modest dimensionality, (...) it might be doable in practice. From the point of view of search algorithms for optimizing structure, much of the machinery of combinatorial optimization could optimize the penalized composite likelihood score by enforcing constraints such that the independence models over different subsets of variables agree on the overlapping sets. (shrink)

Einstein’s Equivalence Principle implies that the Lorentz force equation can be derived from a geodesic equation by imposing a certain condition on the electromagnetic potential. We analyze the quantization of that constraint and find the corresponding differential equations for the phase of the wave function. We investigate these equations in the case of Coulomb potential and show that physically acceptable solutions do not exist. This result signals an inconsistency between Einstein’s Equivalence Principle and Relativistic Quantum Mechanics at (...) an atomic level. (shrink)

According to the prioritized reason model of precedent, precedential constraint is explained in terms of the need for decision-makers to reconcile their decisions with a settled priority order extracted from past cases. The prioritized reason model of precedent departs from the view that common law rules comprise protected reasons for action. In this article I show that a model utilizing protected reasons and the prioritized reason model of precedential constraint are, in an important sense, equivalent. I then offer (...) some reflections on the philosophical significance of this result. I argue that the protected reason model is consistent with the phenomenology of precedential constraint. I suggest an account of precedential reasoning that reconciles the prioritized reason and protected reason models. (shrink)

Brian Pitts has recently claimed to show via straightforward calculation that, at least in the case of Hamiltonian electromagnetism, an arbitrary first-class constraint ``generates not a gauge transformation, but a bad physical change'' (Annals of Physics 351 (2014) pp.382-406; arXiv:1310.2756). We show, via a straightforward calculation, that a transformation generated by an arbitrary first-class constraint relates gauge-equivalent phase space points, vindicating orthodoxy. Pitts, however, is primarily concerned with transformations of entire histories, rather than of instantaneous states. We show (...) that, even in this context, a transformation generated by an arbitrary first-class constraint is also a gauge transformation, once the empirically observed electric field is correctly identified via its dynamical interactions with charge, and not simply given stipulatively as a certain combination of the potential and its derivatives. (shrink)

In this article I attempt to show conclusively that the apparent intrinsic difference between causing collateral damage and directly attacking innocents is an illusion. I show how eleven morally irrelevant alterations can transform an apparently permissible case of harming as a side-effect into an apparently impermissible case of harming as a means. The alterations are as obviously irrelevant as the victims’ skin colour, and consistently treating them as relevant would have unacceptable implications for choices between more and less harmful ways (...) of securing greater goods. This shows not only how the principles philosophers have proposed for distinguishing between these cases cannot withstand scrutiny, but how we can be sure that there are no relevant differences yet to be discovered. I conclude by considering reasons to think that there are deontological constraints against harming, but that they apply just as forcefully against collateral harms as they do against intended harms. (shrink)

The statistical community has brought logical rigor and mathematical precision to the problem of using data to make inferences about a model’s parameter values. The TETRAD project, and related work in computer science and statistics, aims to apply those standards to the problem of using data and background knowledge to make inferences about a model’s specification. We begin by drawing the analogy between parameter estimation and model specification search. We then describe how the specification of a structural equation model entails (...) familiar constraints on the covariance matrix for all admissible values of its parameters; we survey results on the equivalence of structural equation models, and we discuss search strategies for model specification. We end by presenting several algorithms that are implemented in the TETRAD II program. (shrink)

The invariant evolution parameter τ is often used in the formulation of a so-called unconstrained relativistic quantum theoryof a point particle. Such a theory is very elegant, and contains the usual Klein-Gordon or the Dirac particle as a special case. In the present paper we extend the unconstrained theory to describe a continuous set of point particles forming a string or, in general, a membrane of arbitrary dimension p.The action of this system is not invariant with respect to reparametrizations of (...) the evolution parameter τ and therefore there is no constraints among the dynamical variables, and no need for ghosts in the quantized theory. Then we show that such an unconstrained membrane is equivalent to a wiggly membranewhich has variable tension on its (p+1)-dimensional worldsheet. The equations of motion admit the usual well-known Dirac-Nambu-Goto membranes as particular solutions. (shrink)

Recently two pairs of authors have aimed to vindicate the longstanding "orthodox" or conventional claim that a first-class constraint generates a gauge transformation in typical gauge theories such as electromagnetism, Yang-Mills and General Relativity, in response to the Lagrangian-equivalent reforming tradition, in particular Pitts, _Annals of Physics_ 2014. Both pairs emphasize the coherence of the extended Hamiltonian formalism against what they take to be core ideas in Pitts 2014, but both overlook Pitts 2014's sensitivity to ways that one might (...) rescue the claim in question, including an additive redefinition of the electrostatic potential. Hence the bulk of the paper is best interpreted as arguing that the longstanding claim about separate first-class constraints is _either false or trivial_---de-Ockhamization (using more when less suffices by splitting one quantity into the sum of two) being trivial. Unfortunately section 9 of Pitts 2014, a primarily verbal argument that plays no role in other works, is refuted. Pooley and Wallace's inverse Legendre transformation to de-Ockhamized electromagnetism with an additively redefined electrostatic potential, however, opens the door to a precisely analogous calculation introducing a photon mass, which shows that a _second-class primary_ constraint generates a 'gauge transformation' in the exactly same sense---a _reductio ad absurdum_ of the orthodox claim that a first-class constraint generates a gauge transformation _and a second-class constraint does not_. A _reductio_ using massive electromagnetism was presaged in Pitts 2014. Gauge freedom by de-Ockhamization does not require any constraints at all, first-class or second-class, because any dynamical variable in any Lagrangian can be de-Ockhamized into exhibiting trivial additive artificial gauge freedom by splitting one quantity into the sum of two. Physically interesting gauge freedom, however, is typically generated by a tuned sum of first-class constraints, not each first-class constraint alone. (shrink)

We investigate the complexity of finding solutions to infinite recursive constraint satisfaction problems. We show that, in general, the problem of finding a solution to an infinite recursive constraint satisfaction problem is equivalent to the problem of finding an infinite path through a recursive tree. We also identify natural classes of infinite recursive constraint satisfaction problems where the problem of finding a solution to the infinite recursive constraint satisfaction problem is equivalent to the problem of finding (...) an infinite path through finitely branching recursive trees or recursive binary trees. There are a large number of results in the literature on the complexity of the problem of finding an infinite path through a recursive tree. Our main result allows us to automatically transfer such results to give equivalent results about the complexity of the problem of finding a solution to a recursive constraint satisfaction problem. (shrink)

Hamiltonian constraints feature in the canonical formulation of general relativity. Unlike typical constraints they cannot be associated with a reduction procedure leading to a non-trivial reduced phase space and this means the physical interpretation of their quantum analogues is ambiguous. In particular, can we assume that “quantisation commutes with reduction” and treat the promotion of these constraints to operators annihilating the wave function, according to a Dirac type procedure, as leading to a Hilbert space equivalent to that reached by quantisation (...) of the problematic reduced space? If not, how should we interpret Hamiltonian constraints quantum mechanically? And on what basis do we assert that quantisation and reduction commute anyway? These questions will be refined and explored in the context of modern approaches to the quantisation of canonical general relativity. (shrink)

We discuss gauge transformations in QED coupled to a charged spinor field, and examine whether we can gauge-transform the entire formulation of the theory from one gauge to another, so that not only the gauge and spinor fields, but also the forms of the operator-valued Hamiltonians are transformed. The discussion includes the covariant gauge, in which the gauge condition and Gauss's law are not primary constraints on operator-valued quantities; it also includes the Coulomb gauge, and the spatial axial gauge, in (...) which the constraints are imposed on operator-valued fields by applying the Dirac-Bergmann procedure. We show how to transform the covariant, Coulomb, and spatial axial gauges to what we call “common form,” in which all particle excitation modes have identical properties. We also show that, once that common form has been reached, QED in different gauges has a common time-evolution operator that defines time-translation for states that represent systems of electrons and photons. By combining gauge transformations with changes of representation from standard to common form, the entire apparatus of a gauge theory can be transformed from one gauge to another. (shrink)

The interpretation of the violation of Bell-Clauser-Horne inequalities is revisited, in relation with the notion of extension of QM predictions to unmeasurable correlations. Such extensions are compatible with QM predictions in many cases, in particular for observables with compatibility relations described by tree graphs. This implies classical representability of any set of correlations 〈A i 〉, 〈B〉, 〈A i B〉, and the equivalence of the Bell-Clauser-Horne inequalities to a non void intersection between the ranges of values for the unmeasurable (...) correlation 〈A 1 A 2〉 associated to different choices for B. The same analysis applies to the Hardy model and to the “perfect correlations” discussed by Greenberger, Horne, Shimony and Zeilinger. In all the cases, the dependence of an unmeasurable correlation on a set of variables allowing for a classical representation is the only basis for arguments about violations of locality and causality. (shrink)

There exist two conjectures for constraint satisfaction problems of reducts of finitely bounded homogeneous structures: the first one states that tractability of the CSP of such a structure is, when the structure is a model-complete core, equivalent to its polymorphism clone satisfying a certain nontrivial linear identity modulo outer embeddings. The second conjecture, challenging the approach via model-complete cores by reflections, states that tractability is equivalent to the linear identities satisfied by its polymorphisms clone, together with the natural uniformity (...) on it, being nontrivial. We prove that the identities satisfied in the polymorphism clone of a structure allow for conclusions about the orbit growth of its automorphism group, and apply this to show that the two conjectures are equivalent. We contrast this with a counterexample showing that [Formula: see text]-categoricity alone is insufficient to imply the equivalence of the two conditions above in a model-complete core. Taking another approach, we then show how the Ramsey property of a homogeneous structure can be utilized for obtaining a similar equivalence under different conditions. We then prove that any polymorphism of sufficiently large arity which is totally symmetric modulo outer embeddings of a finitely bounded structure can be turned into a nontrivial system of linear identities, and obtain nontrivial linear identities for all tractable cases of reducts of the rational order, the random graph, and the random poset. Finally, we provide a new and short proof, in the language of monoids, of the theorem stating that every [Formula: see text]-categorical structure is homomorphically equivalent to a model-complete core. (shrink)

Veksler and Gunzelmann make an extraordinary claim, which is that sleep deprivation effects and the vigilance decrement are functionally equivalent. Extraordinary claims require extraordinary evidence, which is missing from Veksler and Gunzelmann's study. Their behavioral data offer only weak theoretical constraint, and to the extent their modeling exercise supports any position, it is that these two performance impairments involve functionally distinct underlying mechanisms.

A new scheme is proposed in order to deduce an equation of motion for a spinless charged point particle leading to an equivalent Landau–Lifshitz equation of motion. Consequently Larmor’s formula must be substituted by a new expression for the large distance radiation rate of energy. A constraint appears on the applicability of the Maxwell electromagnetic tensor. The particular case of a sudden force is analyzed in order to show the physical results predicted by the new model. A geometrical rearrangement (...) of the energy explains the balance. (shrink)

This article addresses three questions about well-being. First, is well-being future-sensitive? I.e., can present well-being depend on future events? Second, is well-being recursively dependent? I.e., can present well-being depend on itself? Third, can present and future well-being be interdependent? The third question combines the first two, in the sense that a yes to it is equivalent to yeses to both the first and second. To do justice to the diverse ways we contemplate well-being, I consider our thought and discourse about (...) well-being in three domains: everyday conversation, social science, and philosophy. This article’s main conclusion is that we must answer the third question with no. Present and future well-being cannot be interdependent. The reason, in short, is that a theory of well-being that countenances both future-sensitivity and recursive dependence would have us understand a person’s well-being at a time as so intricately tied to her well-being at other times that it would not make sense to consider her well-being an aspect of her state at particular times. It follows that we must reject either future-sensitivity or recursive dependence. I ultimately suggest, especially in light of arguments based on assumptions of empirical research on well-being, that the balance of reasons favors rejecting future-sensitivity. (shrink)

A new scheme is proposed in order to deduce an equation of motion for a spinless charged point particle leading to an equivalent Landau–Lifshitz equation of motion. Consequently Larmor’s formula must be substituted by a new expression for the large distance radiation rate of energy. A constraint appears on the applicability of the Maxwell electromagnetic tensor. The particular case of a sudden force is analyzed in order to show the physical results predicted by the new model. A geometrical rearrangement (...) of the energy explains the balance. (shrink)

Change seems missing in Hamiltonian General Relativity's observables. The typical definition takes observables to have $0$ Poisson bracket with \emph{each} first-class constraint. Another definition aims to recover Lagrangian-equivalence: observables have $0$ Poisson bracket with the gauge generator $G$, a \emph{tuned sum} of first-class constraints. Empirically equivalent theories have equivalent observables. That platitude provides a test of definitions using de Broglie's massive electromagnetism. The non-gauge ``Proca'' formulation has no first-class constraints, so everything is observable. The gauge ``Stueckelberg'' formulation has (...) first-class constraints, so observables vary with the definition. Which satisfies the platitude? The team definition does; the individual definition does not. Subsequent work using the gravitational analog has shown that observables have not a 0 Poisson bracket, but a Lie derivative for the Poisson bracket with the gauge generator $G$. The same should hold for General Relativity, so observables change locally and correspond to 4-dimensional tensor calculus. Thus requiring equivalent observables for empirically equivalent formulations helps to address the problem of time. (shrink)

This study examines whether L1 English/L2 Spanish learners at different proficiency levels acquire a novel L2 phoneme, the Spanish palatal nasal /ɲ/. While alveolar /n/ is part of the Spanish and English inventories, /ɲ/, which consists of a tautosyllabic palatal nasal+glide element, is not. This crosslinguistic disparity presents potential difficulty for L1 English speakers due to L1 segmental and phonotactic constraints; the closest English approximation is the heterosyllabic sequence /nj/. With these crosslinguistic differences in mind, we ask: Do L1 English (...) learners of L2 Spanish produce acoustically distinct Spanish /n/ and /ɲ/ and Does the distinction of /n/ and /ɲ/ vary by proficiency? In the case that learners distinguish /n/ and /ɲ/, the second question investigates the acoustic quality of /ɲ/ to determine if learners' L2 representation patterns with that of an L1 Spanish representation or if learners rely on an L1 representation and if the acoustic quality of L2 Spanish /ɲ/ varies as a function of proficiency. Beginner and advanced L1 English/L2 Spanish speakers and a comparison group of 10 L1 Spanish/L2 English speakers completed delayed repetition tasks in which disyllabic nonce words were produced in a carrier phrase. English critical items contained an intervocalic heterosyllabic /nj/ sequence ; Spanish critical items consisted of items with either intervocalic onset /ɲ/ or /n/ ['xa.na]. We measured duration and formant contours of the following vocalic portion as acoustic indices of the /n/~/ɲ/ and /ɲ/ ~/nj/ distinctions. Results show that, while L2 Spanish learners produce an acoustically distinct /n/ ~ /ɲ/ contrast even at a low level of proficiency, the beginners produce an intermediate /ɲ/ that falls acoustically between their English /nj/ and the L1 Spanish /ɲ/ while the advanced learners' Spanish /ɲ/ and English /nj/ appear to be in the process of equivalence classification. We discuss these outcomes as they relate to the robustness of L1 phonological constraints in late L2 acquisition coupled with the role of perceptual cues, functional load, and questions of intelligibility. (shrink)

One challenge in explaining neural evolution is the formal equivalence of different computational architectures. If a simple architecture suffices, why should more complex neural architectures evolve? The answer must involve the intense competition for resources under which brains operate. I show how recurrent neural networks can be favored when increased complexity allows for more efficient use of existing resources. Although resource constraints alone can drive a change, recurrence shifts the landscape of what is later evolvable. Hence organisms on either (...) side of a transition boundary may have similar cognitive capacities but very different potential for evolving new capacities. (shrink)

We discuss the main ideas that lie at the foundations of the approximating Hamiltonian method (AHM) in statistical mechanics. The principal constraints for model Hamiltonians to be investigated by AHM are considered along with the main results obtainable by this method. We show how it is possible to enlarge the class of model Hamiltonians solvable by AHM with the help of an example of the BCS-type model.

The contentious question of bilingual processing cost may be recast as a fresh question of code-switching (CS) strategies—quantitative preferences and structural adjustments for switching at particular junctures of two languages. CS strategies are established by considering prosodic and syntactic variables, capitalizing here on bidirectional multi-word CS, spontaneously produced by members of a bilingual community in northern New Mexico who regularly use both languages (Torres Cacoullos and Travis, 2018). CS strategies become apparent by extending the equivalence constraint, which states (...) that bilinguals avoid CS at points of word placement conflict (Poplack, 1980), to examine points of inconsistent equivalence between the languages. Such sites of variable equivalence are junctures where the word strings of the two languages are equivalent only sometimes due to language-internal variable structures. A case in point for the English-Spanish language pair is the boundary between main and complement clauses, where a conjunction occurs always in Spanish but variably in English. The prosodic distancing strategy is to separate the juncture of the two languages. Here the complement clause appears in a different prosodic unit from the main clause, disproportionately as compared both with monolingual benchmarks and with bilinguals' own unilingual English and Spanish. Prosodic distancing serves to mitigate variable equivalence. The syntactic selection strategy is to opt for the variant that is more quantitatively available and more discourse neutral. Here the preference is for the Spanish complementizer que—regardless of main or complement clause language— which is the more frequent option in bilinguals' combined experience in both their languages, whereas English complementizer that is subject to a number of conditioning factors. Syntactic selection serves to restore equivalence at sites of variable equivalence. Discovery of community CS strategies may spur reconsideration of processing cost as a matter of relative difficulty, which will depend on bilinguals' prosodic and syntactic choices at particular CS sites. (shrink)

This volume presents a collection of refereed papers reflecting the state of the art in the area of over-constrained systems. Besides 11 revised full papers, selected from the 24 submissions to the OCS workshop held in conjunction with the First International Conference on Principles and Practice of Constraint Programming, CP '95, held in Marseilles in September 1995, the book includes three comprehensive background papers of central importance for the workshop papers and the whole field. Also included is an introduction (...) by one of the volume editors together with a bibliography listing 243 entries. All in all this is a very useful reference book relevant for all researchers and practitioners interested in hierarchical, partial, and over-constrained systems. (shrink)

It is important to increase computation efficiency of a system at a low cost while holding the system correct. For this realization, addition of new and efficient equivalent transformation rules, whose correctness is assured, is useful. As long as correct ET rules are added to a correct system, the computation result of the system is always correct. Improvement of rules is promoted further by improvement of data structure.In this paper, we improve data structure by introducing interval variables into the usual (...) term domain and add two correct and efficient ET rules, which are promoted by introduction of interval variables, for member constraints on interval variables. These rules are the candidate elimination rule and the common pattern specialization rule. We show by an experiment that computation efficiency is increased by using these rules. (shrink)

Representation and computation of negation is very important in problem solving in various application domains. The purpose of this paper is to propose a new approach to negation. While most theories for negation are based on the logic paradigm, this theory is constructed based on the equivalent transformation computation model, since the ET model provides us with “decomposability of programs,” i.e., a program in the ET model is a set of ET rules and can be synthesized by generating each ET (...) rule independently of other ET rules. To represent negation in the ET model, a constraint is introduced as a pair of an object and a domain. A constraint becomes true when the object is specialized to a ground object within the domain. A negative constraint has a domain that is the complement of the meaning of the corresponding declarative description. Computation of negation in the ET paradigm is realized by equivalent transformation of declarative descriptions including negative constraints. For each negative constraint in a definite clause, a new declarative description is produced and transformed equivalently. When it is transformed to a set of unit clauses, the negative constraint is solved. Each unit clause returns a simple constraint to the “caller” clause. This paper proves two theorems that provide a basis for such equivalent transformation of negative constraints. (shrink)

Call the view that perceptual states can have propositional contents the ‘propositional view’ - or PV for short. Proponents of PV include John McDowell and Susanna Siegel; Anil Gupta and Charles Travis are prominent opponents. In this paper, I wish to address an argument against PV put forward by Anil Gupta. Gupta argues that the conjunction of PV with two further claims, which he calls the ‘Equivalence constraint’ and the ‘reliability constraint’, leads to skepticism. I shall argue (...) that even if we grant EC, Gupta has not given us a compelling reason for rejecting PV and that if we are faced with a choice between rejecting PV and RC, we should reject RC ahead of PV. I shall also suggest that Gupta’s account begs the question against one prominent version of PV. (shrink)

We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional gauge theory methods fail to capture the full classical dynamics of the system and must therefore be deemed inappropriate. We propose a new strategy for consistently quantizing systems with a relational notion of time that does capture the full classical dynamics of the system and allows for evolution parametrized by an equitable (...) internal clock. This proposal contains the minimal temporal structure necessary to retain the ordering of events required to describe classical evolution. In the context of shape dynamics (an equivalent formulation of general relativity that is locally scale invariant and free of the local problem of time) our proposal can be shown to constitute a natural methodology for describing dynamical evolution in quantum gravity and to lead to a quantum theory analogous to the Dirac quantization of unimodular gravity. (shrink)

We propose an operator constraint equation for the wavefunction of the Universe that admits genuine evolution. While the corresponding classical theory is equivalent to the canonical decomposition of General Relativity, the quantum theory contains an evolution equation distinct from standard Wheeler–DeWitt cosmology. Furthermore, the local symmetry principle—and corresponding observables—of the theory have a direct interpretation in terms of a conventional gauge theory, where the gauge symmetry group is that of spatial conformal diffeomorphisms (that preserve the spatial volume of the (...) Universe). The global evolution is in terms of an arbitrary parameter that serves only as an unobservable label for successive states of the Universe. Our proposal follows unambiguously from a suggestion of York whereby the independently specifiable initial data in the action principle of General Relativity is given by a conformal geometry and the spatial average of the York time on the spacelike hypersurfaces that bound the variation. Remarkably, such a variational principle uniquely selects the form of the constraints of the theory so that we can establish a precise notion of both symmetry and evolution in quantum gravity. (shrink)

Some form of agent-relative constraint against the killing of innocent personsis a central principle in deontological moraltheories. In this article I make two claimsabout this constraint. First, I argue that somekillings of innocents performed incircumstances usually not taken to exculpatethe killer are not even pro tanto wrong.Second, I contend that either there is noagent-relative constraint against the killingof innocents or this constraint has a verydifferent shape from that which deontologistsnormally take it to have. My defence of (...) theseclaims rests on two propositions. First, inkilling someone one may actually prolong thatperson''s life. Roughly, life-prolongingkillings are possible, because to kill someoneis to perform an act that causes someone''sdeath and it might well be true that, had onenot performed this act, one''s ``victim'''' wouldhave died earlier. Second, all other thingsbeing equal, killing and causing a person to beunconscious are morally equivalent. Both ofthese propositions are defended in thearticle. (shrink)

Compared to constraint-based causal discovery, causal discovery based on functional causal models is able to identify the whole causal model under appropriate assumptions [Shimizu et al. 2006; Hoyer et al. 2009; Zhang and Hyvärinen 2009b]. Functional causal models represent the effect as a function of the direct causes together with an independent noise term. Examples include the linear non-Gaussian acyclic model, nonlinear additive noise model, and post-nonlinear model. Currently, there are two ways to estimate the parameters in the models: (...) dependence minimization and maximum likelihood. In this article, we show that for any acyclic functional causal model, minimizing the mutual information between the hypothetical cause and the noise term is equivalent to maximizing the data likelihood with a flexible model for the distribution of the noise term. We then focus on estimation of the PNL causal model and propose to estimate it with the warped Gaussian process with the noise modeled by the mixture of Gaussians. As a Bayesian nonparametric approach, it outperforms the previous one based on mutual information minimization with nonlinear functions represented by multilayer perceptrons; we also show that unlike the ordinary regression, estimation results of the PNL causal model are sensitive to the assumption on the noise distribution. Experimental results on both synthetic and real data support our theoretical claims. (shrink)

There are many things—call them ‘experts’—that you should defer to in forming your opinions. The trouble is, many experts are modest: they’re less than certain that they are worthy of deference. When this happens, the standard theories of deference break down: the most popular (“Reflection”-style) principles collapse to inconsistency, while their most popular (“New-Reflection”-style) variants allow you to defer to someone while regarding them as an anti-expert. We propose a middle way: deferring to someone involves preferring to make any decision (...) using their opinions instead of your own. In a slogan, deferring opinions is deferring decisions. Generalizing the proposal of Dorst (2020a), we first formulate a new principle that shows exactly how your opinions must relate to an expert’s for this to be so. We then build off the results of Levinstein (2019) and Campbell-Moore (2020) to show that this principle is also equivalent to the constraint that you must always expect the expert’s estimates to be more accurate than your own. Finally, we characterize the conditions an expert’s opinions must meet to be worthy of deference in this sense, showing how they sit naturally between the too-strong constraints of Reflection and the too-weak constraints of New Reflection. (shrink)

Given the constraints of human partiality and the possible social benefits of widespread genetic technology, allowing for incentive-based inequalities in access in order to boost innovation and diffusion may be the only feasible option available to the post-genomics egalitarian planner. In light of the prevailing ethos that exists in the non-ideal circumstances of society, an initial post-genomics egalitarian goal for all to have equivalent access to comparable genetic interventions seems very unlikely to succeed.While I outline how the initial egalitarian goal (...) can entail either overly prohibitive or overly idealistic prescriptions, I argue that the more recent non-ideal focus has not given adequate attention to how different distributions in genetic access may not only be constrained by, but may also affect the prevailing ethos for better or worse, in turn affecting the range of feasible options into the future. I analyse Farrelly’s Lax Genetic Difference Principle , as an exemplar of a non-ideal post-genomics theorising, and evaluate it in terms of its anticipated effects on the egalitarian ethos. I argue that achieving a more just distribution of access to genetic technologies, by principles that take into account genuine non-ideal considerations, requires a greater awareness of such effects.Finally, I briefly sketch a framework for ‘ethos-proofing’ non-ideal principles, in terms of access to genetic technologies, particularly enhancements, with regard to maintaining and fostering such an egalitarian ethos. (shrink)

Lewis (1981) showed the equivalence between two dominant semantic frameworks for counterfactuals: ordering semantics, which relies on orders between possible worlds, and premise semantics, which relies on sets of propositions (so-called ordering sources). I define a natural, restricted version of premise semantics, expressible premise semantics, which is based on ordering sources containing only expressible propositions. First, I extend Lewis’ (1981) equivalence result to expressible premise semantics and some corresponding expressible version of ordering semantics. Second, I show that expressible (...) semantics are strictly less powerful than their nonexpressible counterparts, even when attention is restricted to the truth values of expressible counterfactuals. Assuming that the expressibility constraint is natural for premise semantics, this result breaks the equivalence between ordering semantics and (expressible) premise semantics. Finally, I show that these results cast doubt on various desirable conjectures, and in particular on a particular defense of the so-called limit assumption. (shrink)

The concept of truth arguably plays a central role in many areas of philosophical theorizing. Yet, what seems to be one of the most fundamental principles governing that concept, i.e. the equivalence between P and , is inconsistent in full classical logic, as shown by the semantic paradoxes. I propose a new solution to those paradoxes, based on a principled revision of classical logic. Technically, the key idea consists in the rejection of the unrestricted validity of the structural principle (...) of contraction. I first motivate philosophically this idea with the metaphysical picture of the states-of-affairs expressed by paradoxical sentences as being distinctively . I then proceed to demonstrate that the theory of truth resulting from this metaphysical picture is, in many philosophically interesting respects, surprisingly stronger than most other theories of truth endorsing the equivalence between P and (for example, the theory vindicates the validity of the traditional laws of excluded middle and of non-contradiction, and also vindicates the traditional constraint of truth preservation on logical consequence). I conclude by proving a cutelimination theorem that shows the consistency of the theory. (shrink)