The basic idea behind the Competitive Exclusion Principle is that species that have similar or identical niches cannot stably coexist in the same place for long periods of time when their common resources are limiting. A more exact definition of the CEP states that, in equilibrium, n number of sympatric species competing for a common set of limiting resources cannot stably coexist indefinitely on fewer than n number of resources. The magnitude or intensity of competition between species (...) is proportional to the degree of overlap in their niches or use of resources. Species that stably coexist do so because there are “important differences” in their niches or use of common limiting resources. (shrink)

This work applies the competitive exclusion principle and the concept of potential competitors as simple axiomatic tools to generalized situations in ecology. These tools enable apparent competition and its dual counterpart to be explicitly evaluated in poorly understood ecological systems. Within this set-theory framework we explore theoretical symmetries and invariances, De Morgan’s laws, frozen evolutionary diversity and virtual processes. In particular, we find that the exclusion principle compromises the geometrical growth of the number of species. (...) By theoretical extending this principle, we can describe interspecific depredation in the dual case. This study also briefly considers the debated situation of intraspecific competition. The ecological consequences of our findings are discussed; particularly, the use of our framework to reinterpret coupled mathematical differential equations describing certain ecological processes. (shrink)

Human Papillomavirus (HPV) types are sexually transmitted infections that cause a number of human cancers. According to the competitive exclusion principle in ecology, HPV types that have lower transmission probabilities and shorter durations of infection should be outcompeted by more virulent types. This, however, is not the case, as numerous HPV types co-exist, some which are less transmissible and more easily cleared than others. This paper examines whether this exception to the competitive exclusion principle (...) can be explained by the aggregation of infection with HPV types, which results in patchy spatial distributions of infection, and what implications this has for the effect of vaccination on multiple HPV types. A deterministic transmission model is presented that models the patchy distribution of infected individuals using Lloyd’s mean crowding. It is first shown that higher aggregation can result in a reduced capacity for onward transmission and reduce the required efficacy of vaccination. It is shown that greater patchiness in the distribution of lower prevalence HPV types permits co-existence. This affirms the hypothesis that the aggregation of HPV types provides an explanation for the violation of the competitive exclusion principle. Greater aggregation of lower prevalence types has important implications where type-specific HPV vaccines also offer cross-protection against non-target types. It is demonstrated that the degree of cross-protection can be less than the degree of vaccine protection conferred against directly targeted types and still result in the elimination of non-target types when these non-target types are patchily distributed. (shrink)

The complexity and heterogeneity of causes influencing ecology’s domain challenge its capacity to generate a general theory without exceptions, raising the question of whether ecology is capable, even in principle, of achieving the sort of theoretical success enjoyed by physics. Weber has argued that competition theory built around the Competitive Exclusion Principle (especially Tilman’s resource-competition model) offers an example of ecology identifying a law-like causal regularity. However, I suggest that as Weber presents it, the CEP is (...) not yet a causal regularity. Instead, I argue that the scientific understanding in Tilman’s theory takes a different form. The theory explains through a structure I call “channeling explanation” which does not depend on deduction from general laws, but rather builds on constraints and trade-offs represented in state-space. Recognizing this structure supports the more general point that ecology and other so-called special sciences can reveal novel theoretical approaches to philosophy of science when approached with openness to their uniqueness. (shrink)

This article examines some of the main tenets of competition theory in light of the theory of evolution and the concept of an ecological niche. The principle of competitive exclusion and the related assumption that communities exist at competitive equilibrium - fundamental parts of many competition theories and models - may be violated if non-equilibrium conditions exist in natural communities or are incorporated into competition models. Furthermore, these two basic tenets of competition theory are not compatible (...) with the theory of evolution. Variation in ecologically significant environmental factors and non-equilibrium in population numbers should occur in most natural communities, and such changes have important effects on community relations, niche overlap, and the evolution of ecosystems. Ecologists should view competition as a process occurring within a complexdynamic system, and should be wary of theoretical positions built upon simple laboratory experiments or simplistic mathematical models.In considering the relationship between niche overlap and competition, niche overlap should not be taken as a sufficient condition for competition; many factors may prevent or diminish competition between populations with similar resource utilization patterns. The typically opposing forces of intraspecific and interspecific competition need to be simultaneously considered, for it is the balance between them that in large part determines niche boundaries. (shrink)

Despite the reality of intersex individuals whose biological markers do not necessarily all point towards a traditional binary understanding of either male or female, the vast majority of sports divide competition into categories based on a binary notion of biological sex and develop policies and regulations to police the divide. In so doing, sports governing bodies (SGBs) adopt an imperfect model of biological sex in order to serve their particular purposes, which, typically, will include protecting the fundamental sporting value of (...) fair competition. Yet, one potential consequence of enforcing such an approach would seem to be the exclusion or marginalization of individuals whose biological development does not fit within the binary model, whether due to genetics or through a choice to undergo medical intervention to better represent a chosen gender identity. Any such exclusion or marginalization will inevitably tend to undermine another fundamental value of sport, that of inclusivity. In the context of those with differences of sex development, SGBs appear to be faced with a difficult problem: dealing with a conflict between two fundamental values of sport. Different approaches to this problem have been suggested, with some academics proposing that sports organisations, in general, ought to prioritise fairness above, while others suggest the need to ‘balance’ competing values or even to prioritise inclusion over fairness. However, it is argued that any of these approaches are, in principle, justifiable as any sport should be free to prioritise or balance its own values. What seems more important for any SGB is the need for a rational and transparent justification of regulations that pursue fair competition at the expense of inclusivity. Furthermore, where fair competition and inclusivity are fundamental values, any such justification would seem to demand adherence to some basic norms. First, the regulations should be built on (and articulate) a consistent and principled basis of what ‘fair competition’ means in a particular sport. Second, any regulations should only exclude or restrict participation to the minimum degree necessary to achieve the sense of fair competition so articulated. Third, SGBs should be transparent about what their values are and where their priorities lie so that participants and other stakeholders are able to make an informed choice as to whether they wish to participate in, support, or be associated with a particular sport. With reference to the adoption of the Eligibility Regulations for Athletes with Differences of Sex Development (the ‘DSD Regulations’) by the International Association of Athletic Federations (IAAF), this article seeks to evaluate whether the approach of the IAAF satisfied these basic requirements. (shrink)

Exact definitions in physical and biological terms of the coefficients in Volterra's (1926, 1931) original competition equations are indispensable for the understanding of the system. In agreement with Volterra's own, but not quite sufficient specifications, it is tried in this paper to give more precise definitions of the parameters used by Volterra. This leads to some consequences; i.a. that there does not exist a principle of competitive exclusion. In order to allow for competitive exclusion — (...) or for stabilization — the Volterra equations need additional biophysical specifications and mathematical modifications. Some such modifications are proposed, for instance for aggressive interference as a function of population numbers. (shrink)

Studies of coexistence are based ultimately on the assumption that competitive exclusion is a general and accredited phenomenon in nature. However, the ecological and evolutionary impact of interspecific competition is of questionable significance. Review of three reputed examples of competitive exclusion in the field (Aphytis wasps, red and grey squirrels, and triclads) demonstrates that the widely-accepted competition-based interpretations are unlikely, that alternative explanations are overlooked, and that all other reported cases need critical reinvestigation. Although interspecific competition (...) does undoubtedly occur, the evidence suggests it is usually too weak and intermittent a force to achieve competitive exclusion or any other ecologically-significant result, except perhaps rarely and on a minor scale. Coexistence and community structure are therefore not ecological conditions to be especially accounted for, especially since their inherently comparative methods generate information that is largely superficial. Alternative questions that relate directly to species, the units of diversity, are discussed and they emphasize the primary habitat requirements of species, which are fixed during speciation. Neither the comparative approach of coexistence studies, nor the investigation of pattern is likely to be profitable, since the acquisition of species-specific characteristics during speciation requires historical research. At least one alternative theory of ecology, based on the close adaptation of organisms to the environment, is available. (shrink)

It is strange to note so little discussion of the exclusion principle in the philosophical literature. Philosophers, largely engrossed in their perennial problems, are hardly aware of the fact that, during the last two decades, there has been introduced into physical methodology a principle of utmost philosophical importance, easily rivaling that of relativity and, in some respects, indeed that of causality. Discovered by Pauli in 1925, it immediately elucidated a whole realm of physical facts and was accepted (...) by physicists with wide acclaim. Called the exclusion principle—or Pauli principle, or principle of anti-symmetry—it was embodied in the axiomatics of quantum mechanics; its peculiar methodological significance passed out of view. (shrink)

This paper concerns the question of whether Pauli's Exclusion Principle (EP) vindicates the contingent truth of Leibniz's Principle of the Identity of Indiscernibles (PII) for fermions as H. Weyl first suggested with the nomenclature ‘Pauli–Leibniz principle’. This claim has been challenged by a time-honoured argument, originally due to H. Margenau and further articulated and champione by other authors. According to this argument, the Exclusion Principle—far from vindicating Leibniz's principle—would refute it, since the same (...) reduced state, viz. an improper mixture, can be assigned as a separate state to each fermion of a composite system in antisymmetric state. As a result, the two fermions do have the same monadic state-dependent properties and hence are indiscernibles. PII would then be refuted in its strong version (viz. for monadic properties). I shall argue that a misleading assumption underlies Margenau's argument: in the case of two fermions in antisymmetric state, no separate states should be invoked since the states of the two particles are entangled and the improper mixture—assigned to each fermion by reduction—cannot be taken as an ontologically separate state nor consequently as encoding monadic properties. I shall then conclude that the notion of monadic properties together with the strong version of PII are inapplicable to fermions in antisymmetric state and this undercuts Margenau's argument. (shrink)

The Pauli Exclusion Principle and the reduction of chemistry have been the subject of considerable philosophical debate, The present article considers the view that the lack of derivability of the Exclusion Principle represents a problem for physics and denies the reduction of chemistry to quantum mechanics. The possible connections between the Exclusion Principle and the hidden variable debate are also briefly criticised.

We give a derivation of exclusion principles for the elementary particles of the standard model, using simple mathematical principles arising from a set theory of identical particles. We apply the theory of permutation group actions, stating some theorems which are proven elsewhere, and interpreting the results as a heuristic derivation of Pauli's Exclusion Principle (PEP) which dictates the formation of elements in the periodic table and the stability of matter, and also a derivation of quark confinement. We (...) arrive at these properties by using a symmetry property of collections of the particles themselves as compared for example to the symmetry property of their wave function under interchange of two particles. (shrink)

There is hardly another principle in physics with wider scope of applicability and more far-reaching consequences than Pauli's exclusion principle. This book explores the principle's origin in the atomic spectroscopy of the early 1920s, its subsequent embedding into quantum mechanics, and later experimental validation with the development of quantum chromodynamics. The reconstruction of this crucial historic episode provides an excellent foil to reconsider Kuhn's view on incommensurability. The author defends the prospective rationality of the revolutionary transition (...) from the old to the new quantum theory around 1925 by focusing on the way Pauli's principle emerged as a phenomenological rule 'deduced' from some anomalous phenomena and theoretical assumptions of the old quantum theory. The subsequent process of validation is historically reconstructed and analysed within the framework of 'dynamic Kantianism'. (shrink)

The Pauli exclusion principle is interpreted using a geometrical theory of electrons. Spin and spatial motion are described together in an eight dimensional spinor coordinate space. The field equation derives from the assumption of conformal waves. The Dirac wave function is a gradient of the scalar wave in spinor space. Electromagnetic and gravitational interactions are mediated by conformal transformations. An electron may be followed through a sequence of creation and annihilation processes. Two electrons are branches of a single (...) particle. Each satisfies a Dirac equation, but together they are a solution of the curvature condition. As two so identified electrons approach each other, the exclusion principle develops from the boundary conditions in spinor space. The gradient motion does not allow the particles to overlap. Since the spinor-gradient of the scalar wave function is odd in the coordinates, the sign of the wave function must change at the electron-electron boundary. The exclusion principle becomes geometry intrinsic and all electrons are combined into one field. Further applications are proposed including the possibility of improved numerical calculations in atomic and molecular systems. There also may be extensions to nuclear or particle physics. Implications are expected for the properties of rotating objects in a gravitational field. (shrink)

The modern state of the Pauli exclusion principle studies is discussed. The Pauli exclusion principle can be considered from two viewpoints. On the one hand, it asserts that particles with half-integer spin (fermions) are described by antisymmetric wave functions, and particles with integer spin (bosons) are described by symmetric wave functions. This is a so-called spin-statistics connection. The reasons why the spin-statistics connection exists are still unknown, see discussion in text. On the other hand, according to (...) the Pauli exclusion principle, the permutation symmetry of the total wave functions can be only of two types: symmetric or antisymmetric, all other types of permutation symmetry are forbidden; although the solutions of the Schrödinger equation may belong to any representation of the permutation group, including the multi-dimensional ones. It is demonstrated that the proofs of the Pauli exclusion principle in some textbooks on quantum mechanics are incorrect and, in general, the indistinguishability principle is insensitive to the permutation symmetry of the wave function and cannot be used as a criterion for the verification of the Pauli exclusion principle. Heuristic arguments are given in favor that the existence in nature only the one-dimensional permutation representations (symmetric and antisymmetric) are not accidental. As follows from the analysis of possible scenarios, the permission of multi-dimensional representations of the permutation group leads to contradictions with the concept of particle identity and their independence. Thus, the prohibition of the degenerate permutation states by the Pauli exclusion principle follows from the general physical assumptions underlying quantum theory. (shrink)

We present a theory of cooperative-competitive intelligence (CCI), its measures, research program, and applications that stem from it. Within the framework of this theory, satisficing sub-optimal behavior is any behavior that does not promote a decrease in the prospective control of the functional action diversity/unpredictability (D/U) potential of the agent or team. This potential is defined as the entropy measure in multiple, context-dependent dimensions. We define the satisficing interval of behaviors as CCI. In order to manifest itself at individual (...) or team level, this capacity harnesses properties such as degeneracy, pleiotropy (pluri-potentiality), synergies, and metastability. Intelligence is embodied because intelligent behavior is deeply dependent on body functionalities, defined as entropy measures. We base our theory on three principles: (a) relativity of functional entropy/ information in agent (team)-environment systems, (b) tendency toward the satisficing level of D/U potential, and (c) tendency toward the non-decreasing D/U potential. The conjunction of these three principles provides existence of sub-optimal behaviors associated with CCI. First, we deal with the problem of how to reduce multidimensional behavior to a concept that accounts for the vast set of scenarios in which CCI is manifested. Secondly, we define and discuss the three interacting principles that underpin CCI behavior as well as providing an outline for a future CCI research program supported by agent￾based modeling and empirical research. Finally, we provide some preliminary practical issues that stem from the theory. (shrink)

Despite its importance to Chemistry, the Pauli Exclusion Principle appears as a rather ad hoc addition to quantum mechanics. In this paper a description of its origin is given together with a critical discussion of its use and significance in Chemistry and Quantum Physics.

It is often argued that higher-level special-science properties cannot be causally efficacious since the lower-level physical properties on which they supervene are doing all the causal work. This claim is usually derived from an exclusion principle stating that if a higher-level property F supervenes on a physical property F* that is causally sufficient for a property G, then F cannot cause G. We employ an account of causation as difference-making to show that the truth or falsity of this (...) principle is a contingent matter and derive necessary and sufficient conditions under which a version of it holds. We argue that one important instance of the principle, far from undermining non-reductive physicalism, actually supports the causal autonomy of certain higher-level properties. (shrink)

The electronic and muonic hydrogen energy levels are calculated very accurately [1] in Quantum Electrodynamics (QED) by coupling the Dirac Equation four vector (c ,mc2) current covariantly with the external electromagnetic (EM) field four vector in QED’s Interactive Representation (IR). The c -Non Exclusion Principle(c -NEP) states that, if one accepts c as the electron/muon velocity operator because of the very accurate hydrogen energy levels calculated, the one must also accept the resulting electron/muon internal spatial and time coordinate (...) operators (ISaTCO) derived directly from c without any assumptions. This paper does not change any of the accurate QED calculations of hydrogen’s energy levels, given the simplistic model of the proton used in these calculations [1]. The Proton Radius Puzzle [2, 3] may indicate that new physics is necessary beyond the Standard Model (SM), and this paper describes the bizarre, and very different, situation when the electron and muon are located “inside” the spatially extended proton with their Centers of Charge (CoCs) orbiting the proton at the speed of light in S energy states. The electron/muon center of charge (CoC) is a structureless point that vibrates rapidly in its inseparable, non-random vacuum whose geometry and time structure are defined by the electron/muon ISaTCO discrete geometry. The electron/muon self mass becomes finite in a natural way due to the ISaTCOs cutting off high virtual photon energies in the photon propagator. The Dirac-Maxwell-Wilson (DMW) Equations are derived from the ISaTCO for the EM fields of an electron/muon, and the electron/muon “look” like point particles in far field scattering experiments in the same way the electric field from a sphere with evenly distributed charge “e” “looks” like a point with the same charge in the far field (Gauss Law). The electron’s/muon’s three fluctuating CoC internal spatial coordinate operators have eight possible eigenvalues [4, 5, 6] that fall on a spherical shell centered on the electron’s CoM with radius in the rest frame. The electron/muon internal time operator is discrete, describes the rapid virtual electron/positron pair production and annihilation. The ISaTCO together create a current that produce spin and magnetic moment operators, and the electron and muon no longer have “intrinsic” properties since the ISaTCO kinematics define spin and magnetic moment properties. (shrink)

A nonnegative interger is called a number, a collection of numbers a set and a collection of sets a class. We write ε for the set of all numbers, o for the empty set, N(α) for the cardinality of $\alpha, \subset$ for inclusion and $\subset_+$ for proper inclusion. Let α, β 1 ,...,β k be subsets of some set ρ. Then α' stands for ρ-α and β 1 ⋯ β k for β 1 ∩ ⋯ ∩ β k . For (...) subsets α 1 ,..., α r of ρ we write: $\alpha_\sigma - \{x \in v \ (\nabla i) \lbrack i \in \sigma \Rightarrow x \in \alpha_i\rbrack\} \text{for} \sigma \subset (1, \ldots, r),\\ s_i = \sum \{N(\alpha_\sigma) \mid \sigma \subset (1,\ldots, r) \& N(\sigma) = i\}, \text{for} 0 \leqq i \leqq r$ . Note that α 0 = v, hence s 0 = N(v). If the set v is finite, the classical inclusion-exclusion principle (abbreviated IEP) states $(a) N(\alpha_1 \cup \cdots \cup \alpha_r) = \sum^r_{t=1} (-1)^{t-1} s_t = \sum_{o \subset_+\sigma \subset (1,\ldots,r)}$ (b) N(α' 1 ⋯ α' r ) = ∑ r t=0 (-1) t s t = ∑ (-1) N(σ) N (α σ ). In this paper we generalize (a) and (b) to the case where α 1 ,⋯, α r are subsets of some countable but isolated set v. Then the role of the cardinality N(α) of the set α is played by the RET (recursive equivalence type) Req α of α. These generalization of (a) and (b) are proved in § 3. Since they involve recursive distinctness, this notion is discussed in § 2. In § 4l we consider a natural extension of "the sum of the elements of a finite set σ" to the case where σ is countable. § 5 deals with valuations, i.e., certain mappings μ from classes of isolated sets into the collection λ of all isols which permit us to further generalize IEP by substituting μ(α) for $\operatorname{Req} \alpha$. (shrink)

In this paper we explore Jaegwon Kim's principle of explanatory exclusion. Kim's support for the principle is clarified and we critically evaluate several versions of the dual explananda response authors have offered to undermine it. We argue that none of the standard versions of the dual explananda reply are entirely successful and propose an alternative approach that reveals a deep tension in Kim's metaphysics. We argue that Kim can only retain the principle of explanatory exclusion (...) if he abandons his longstanding critique of nonreductive physicalism. (shrink)

Perhaps no concept has been thought more important to ecological theorizing than the niche. Without it, technically sophisticated and well-regarded accounts of character displacement, ecological equivalence, limiting similarity, and others would seemingly never have been developed. The niche is also widely considered the centerpiece of the best candidate for a distinctively ecological law, the competitive exclusion principle. But the incongruous array and imprecise character of proposed definitions of the concept square poorly with its apparent scientific centrality. I (...) argue this definitional diversity and imprecision reflects a problematic conceptual indeterminacy that challenges its putative indispensability in ecology. (shrink)

A short review is given of three experimental works on tests of the Pauli Exclusion Principle (PEP) in which the author has been involved during the last 10 years. In the first work a search for anomalous carbon atoms was done and a limit on the existence of such atoms was determined, $^{12}\tilde{\mathrm{C}}$ /12C <2.5×10−12. In the second work PEP was tested with the NEMO-2 detector and the limits on the violation of PEP for p-shell nucleons in 12C (...) were obtained. Specifically, transitions to the fully occupied 1s 1/2-shell yielded a limit of 4.2×1024 y for the process with the emission of a γ-quantum. Similarly limits of 3.1×1024 y for β − and 2.6×1024 y for β + Pauli-forbidded transition of 12C → 12Ñ( $^{12}\tilde{\mathrm{B}}$ ) are reported. In the third work it was assumed that PEP is violated for neutrinos, and thus, neutrinos obey at least partly the Bose-Einstein statistics. Consequences of the violation of the exclusion principle for double beta decays were considered. This violation strongly changes the rates of the decays and modifies the energy and angular distributions of the emitted electrons. It was shown that pure bosonic neutrinos are excluded by the present experimental data. In the case of partly bosonic neutrinos the analysis of the existing data allows one to put an upper bound for sin 2 χ<0.6. The sensitivity of future measurements is also evaluated. (shrink)

The paradox of biological diversity is the key problem of theoretical ecology. The paradox consists in the contradiction between the competitive exclusion principle and the observed biodiversity. The principle is important as the basis for ecological theory. On a relatively simple model we show a mechanism of indefinite coexistence of complete competitors which violates the known formulations of the competitive exclusion principle. This mechanism is based on timely recovery of limiting resources and their (...) spatio-temporal allocation between competitors. Because of limitations of the black-box modeling there was a problem to formulate the exclusion principle correctly. Our white-box multiscale model of two-species competition is based on logical deterministic individual-based cellular automata. This approach provides an automatic deductive inference on the basis of a system of axioms, and gives a direct insight into mechanisms of the studied system. It is one of the most promising methods of artificial intelligence. We reformulate and generalize the competitive exclusion principle and explain why this formulation provides a solution of the biodiversity paradox. In addition, we propose a principle of competitive coexistence. (shrink)

In this paper we describe an experimental test of the validity of the Pauli Exclusion Principle (for electrons) which is based on a straightforward idea put forward a few years ago by Ramberg and Snow (Phys. Lett. B 238:438, 1990). We perform a very accurate search of X-rays from the Pauli-forbidden atomic transitions of electrons in the already filled 1S shells of copper atoms. Although the experiment has a very simple structure, it poses deep conceptual and interpretational problems. (...) Here we describe the experimental method and recent experimental results, which we interpret in the framework of quon theory. We also present future plans to upgrade the experimental apparatus using Silicon Drift Detectors. (shrink)

We present an experimental test of the validity of the Pauli Exclusion Principle for electrons based on the concept put forward a few years ago by Ramberg and Snow. In this experiment we perform a very accurate search of X-rays from the Pauli-forbidden atomic transitions of electrons in the already filled 1S shells of copper atoms. Although the experiment has a simple structure, it poses deep conceptual and interpretational problems. Here we describe the experimental method and recent experimental (...) results, which we interpret as an upper limit for the probability to violate the Pauli Exclusion Principle. We present also future plans to upgrade the experimental apparatus using Silicon Drift Detectors. (shrink)

I argue that the completeness of physics is composed of two distinct claims. The first is the commonly made claim that, roughly, every physical event is completely causally determined by physical events. The second has rarely, if ever, been explicitly stated in the literature and is the claim that microphysics provides a complete inventory of the fundamental categories that constitute both the causal features and intrinsic nature of all the events that causally affect the physical universe. After showing that these (...) claims are distinct, I argue that they can be used to solve a difficulty with existing responses to the exclusion problem—namely, that these existing responses also undermine the powerful causal argument for physicalism. Recognizing that there are two kinds of completeness opens up room for the nonreductive physicalist to solve the exclusion problem while also endorsing a modified, cogent causal argument for a kind of physicalism compatible with her position. (shrink)

It is shown that classical Dirac fields with the same couplings obey the Pauli exclusion principle in the following sense: If at a certain time two Dirac fields are in different states, they can never reach the same one. This is geometrically interpreted as analogous to the impossibility of crossing of trajectories in the phase space of a dynamical system. An application is made to a model in which extended particles are represented as solitary waves of a set (...) of several fundamental, confined nonlinear Dirac fields, with the result that the same mechanism accounts both for fermion and boson behaviors. (shrink)

Both bosons and fermions satisfy a strong version of Leibniz’s Principle of the Identity of Indiscernibles (PII), and so are ontologically on a par with respect to the PII. This holds for non-entangled, non-product states and for physically entangled states—as it has been established in previous work. In this paper, the Leibniz strategy is completed by including the (bosonic) symmetric product states. A new understanding of Pauli’s Exclusion Principle is provided, which distinguishes bosons from fermions in a (...) peculiar ontological way. Finally, the program as a whole is defended against substantial objections. (shrink)

Competition between scientific hypotheses is not always a matter of mutual exclusivity. Consistent hypotheses can compete to varying degrees either directly or indirectly via a body of evidence. We motivate and defend a particular account of hypothesis competition by showing how it captures these features. Computer simulations of Bayesian inference are used to highlight the limitations of adopting mutual exclusivity as a simplifying assumption to model scientific reasoning, particularly due to the exclusion of hypotheses that may be true. We (...) end with a case study demonstrating the subtleties involved in hypothesis competition in scientific practice. (shrink)

The principle of causal exclusion is based on two distinct causal notions: causal sufficiency and causation simpliciter. The principle suggests that the former has the power to exclude the latter. But that is problematic since it would amount to claiming that sufficient causes alone can take the roles of causes simpliciter. Moreover, the principle also assumes that events can sometimes have both sufficient causes and causes simpliciter. This assumption is in conflict with the first part of (...) the principle that claims that sufficient causes must exclude causes simpliciter. (shrink)

I present an attempt at an explication of the ecological theory of interspecific competition, including its explanatory role in community ecology and evolutionary biology. The account given is based on the idea that law-like statements play an important role in scientific theories of this kind. I suggest that the principle of competitive exclusion is such a law, and that it is evolutionarily invariant. The principle's empirical status is defended and implications for the ongoing debates on the (...) existence of biological laws are discussed. (shrink)

Next SectionThis paper provides a lexical entry schema for exclusives covering the adverbs only, just, exclusively, merely, purely, solely, simply, and the adjectives only, sole, pure, exclusive and alone. We argue, on the basis of inter-paraphrasability relations among these exclusives and entailments involving at least and at most, that all of these items make an at-issue contribution of an upper bound on the viable answers to the current question under discussion (expressible with at most), and signal that a lower bound (...) on those answers (expressible with at least) is taken for granted. The lexical entry schema accommodates two main points of variation, which makes it possible to capture the differences in meaning among these terms: (i) semantic type (restricted to the class of modifiers), and (ii) constraints on the current question under discussion or the strength ranking over its alternative possible answers. We propose 22 different specific instantiations of the schema for exclusives in English. (shrink)