In this essay, we examine the use of resting state fMRI data for psychological inferences. We argue that resting state studies hold the paired promises of discovering novel functional brain networks, and of avoiding some of the limitations of task-based fMRI. However, we argue that the very features of experimental design that enable resting state fMRI to support exploratory science also generate a novel confound. We argue that seemingly key features of resting state functional connectivity networks may be artefacts resulting (...) from sampling a ‘mixture distribution’ of diverse brain networks active at different times during the scan. We explore the consequences of this ‘mixture view’ for attempts to theorize about the cognitive or psychological functions of resting state networks, as well as the value of exploratory experiments. (shrink)

In this article, I show that the semantics one adopts for mass terms constrains the metaphysical claims one can make about mixtures. I first expose why mixtures challenge a singularist approach based on mereological sums. After discussing an alternative, non-singularist approach, I take chemistry into account and explain how it changes our perspective on these issues.

From a modern point of view, compounds are contrasted with elements of which they are composed, and the two categories combine to give the category of substances. Mixtures, on the other hand, might be understood to contrast with pure substances (substances in isolation), so that mixtures are quantities of matter containing several substances (be they compounds or uncombined elements) whereas pure substances are understood to be quantities of matter exhausting the material contents of a region of space which contain only (...) one substance, and might be either a compound or an element. But heterogeneous quantities of matter (comprising several phases) might also be understood to be mixtures. Thus, it is common to speak of a mixture of ice, liquid water and water vapour in equilibrium at the triple point of water, although there is only a single substance present. The general concept of mixture as treated by Gibbs’ phase rule is a quantity of matter comprising either several substances or several phases, “or” being used in the inclusive sense. Gibbs’ phase rule is a relatively recent development in the history of the concept of chemical substance, dating from the latter half of the nineteenth century. The concepts and distinctions it presupposes have not always been apparent. I trace some of the important conceptual developments underlying the important distinctions at issue here from Aristotle, who didn’t distinguish either substance and phase, or what are now called compounds and solutions. (shrink)

When elements join together in a mixture, those elements remain in the mixture, but only virtually. They are present with their powers, but without their substantial forms. When the mixture corrupts, the elements come to be actually present. And so my question: according to St. Thomas, are the elements that come to be actually present as a result of the corruption of the mixed body numerically identical with the elements that came together to create the mixture? (...) I answer yes. This answer entails not only that St. Thomas believes in the doctrine of “gappy existence”, but that he believes gappy existence can occur purely naturally, with no Divine intervention required. Both entailments are controversial. The second will be widely viewed as entirely indefensible: this paper provides a defense. (shrink)

This paper takes up issues related to the notion of chemical substances arising from their mereological and modal features. Related notions are elements and compounds, into which substances are sub-divided, and the general notion of mixture, which as a special case might involve several substances, but covers other cases too. These are essentially macroscopic concepts. Some of the chemical arguments for this claim have been presented elsewhere. The present paper is a metaphysical treatment of matter as categorised by the (...) major chemical concepts bearing on distinctions between homogeneous and heterogeneous matter, and between a single and several substances. (shrink)

Some points are made about substance properties in their role of introducing mass terms. In particular, two conditions of distributivity and cumulativity of mass predicates expressing these properties are not the independent pair they first appear to be. A classification of macroscopic substance concepts is developed. This needs to be complemented in some way by the introduction of a modal qualification reminiscent of Aristotle's distinction between actual and potential presence of substances in a mixture. Consideration of the latter feature (...) has prompted Joe Earley to raise the question of whether there is any salt in the sea. I try to argue that there is. (shrink)

Cavendish is critical of two of the experimental sciences of her day: chemistry and microscopy. Rather than creating new things, as their practitioners claim, they produce 'hermaphroditical mixtures'. I trace this startling metaphor to the alchemical tradition and suggest how its origins can help us to understand Cavendish's position. In her view, the chemists and microscopists exaggerate their own power and creativity, and fail to recognise that human creativity belongs primarily to imagination. I show how this theme is worked out (...) in Cavendish's paired texts, Observations on Experimental Philosophy and the fictional Blazing World. (shrink)

A mixture preorder is a preorder on a mixture space (such as a convex set) that is compatible with the mixing operation. In decision theoretic terms, it satisfies the central expected utility axiom of strong independence. We consider when a mixture preorder has a multi-representation that consists of real-valued, mixture-preserving functions. If it does, it must satisfy the mixture continuity axiom of Herstein and Milnor (1953). Mixture continuity is sufficient for a mixture-preserving multi-representation (...) when the dimension of the mixture space is countable, but not when it is uncountable. Our strongest positive result is that mixture continuity is sufficient in conjunction with a novel axiom we call countable domination, which constrains the order complexity of the mixture preorder in terms of its Archimedean structure. We also consider what happens when the mixture space is given its natural weak topology. Continuity (having closed upper and lower sets) and closedness (having a closed graph) are stronger than mixture continuity. We show that continuity is necessary but not sufficient for a mixture preorder to have a mixture-preserving multi-representation. Closedness is also necessary; we leave it as an open question whether it is sufficient. We end with results concerning the existence of mixture-preserving multi-representations that consist entirely of strictly increasing functions, and a uniqueness result. (shrink)

This paper concerns the classification of the process of mixture, for Aristotle, and the related issue of the manner in which the ingredients remain present once mixed. I argue that mixture is best viewed as a kind of substantial generation in the context of the GC and, accordingly, that the ingredients do not enjoy the kind of strong presence within a mixture usually attributed to them. To do this, I critically examine the most promising versions of the (...) standard view and offer a new interpretation of Aristotle’s treatment of a puzzle about mixture in GC 1.10. (shrink)

This paper analyzes the theory of mixtures, material substances and corpuscles put forward by the Portuguese Thomistic philosopher Francisco Soares Lusitano. It has been argued that the incapacity of the Aristotelian-Thomistic tradition to reconcile an Aristotelian theory of mixtures with hylomorphism opened the way to the triumph of atomism in the seventeenth century. By analyzing Soares Lusitano’s theory of mixtures, this paper aims to demonstrate that early modern Thomism not only rendered the Aristotelian notion of elements compatible with the metaphysical (...) bases of hylomorphism, but further incorporated an explanation of physical phenomena based upon the notion that bodies were basically made up of small and subtle corpuscles. By doing so, it shows that, contrary to what is so often claimed, early modern corpuscularism was not intrinsically incompatible with late Aristotelian philosophy. (shrink)

This paper investigates continuities and changes in the definition of sickle cell disease in 1950s Brazil, taking into account that diseases have a history and are recognized as such according to the knowledge and perceptions available in a certain historical period and specific location. In the post-war era, new diagnostic tools, inheritance theories and, in particular, discussions on the concepts of race and racial relations, both nationally and internationally, were changing previous racialist and racist views. Nonetheless, the Brazilian medical interpretations (...) of sickle cell disease continued to racialize it and even use deep-rooted racist formulations to explain its symptoms or the existence of the disease. It is argued that the celebration of racial mixture and racial democracy might have concealed racist presumptions biasing the study of sickle cell disease. Although race as a biological concept gradually gave way to other genetic expressions, in Brazilian medical papers on sickle cell disease, race continued to influence the interpretation of the disease, along with the persistence of concepts of heredity through blood mixture. (shrink)

This paper investigates continuities and changes in the definition of sickle cell disease in 1950s Brazil, taking into account that diseases have a history and are recognized as such according to the knowledge and perceptions available in a certain historical period and specific location. In the post-war era, new diagnostic tools, inheritance theories and, in particular, discussions on the concepts of race and racial relations, both nationally and internationally, were changing previous racialist and racist views. Nonetheless, the Brazilian medical interpretations (...) of sickle cell disease continued to racialize it and even use deep-rooted racist formulations to explain its symptoms or the existence of the disease. It is argued that the celebration of racial mixture and racial democracy might have concealed racist presumptions biasing the study of sickle cell disease. Although race as a biological concept gradually gave way to other genetic expressions, in Brazilian medical papers on sickle cell disease, race continued to influence the interpretation of the disease, along with the persistence of concepts of heredity through blood mixture. (shrink)

In his works on natural sciences, primarily in the Physics, Aristotle focuses on different forms of metabolē and distinguishes movement in general from substantial change. The On generation and corruption deals with the latter. When reading this treatise, one should pay particular attention to the concept of mixture. Apart from being the subject of a specific chapter, the problem of mixture permeates the whole work. But what exactly is mixture? Is it a simple combination of small parts? (...) Can a compound of water and wine be called mixture? If so, is this mixture and nothing more? In the course of the discussion, it is argued that the Aristotelian idea of mixis does not correspond to the concept that is usually associated with it. Rather, it is shown that mixis is fundamental for comprehending the physical world and constitutes not only the term per quem the first elements of all material bodies originate, but also plays a fundamental role in all natural sciences, particularly, in biology. (shrink)

Abstractabstract:Karl Marx’s acerbic observation in the opening lines of The Eighteenth Brumaire that “all facts and personages of great importance in world history occur the first time as tragedy, the second as farce” may be profitably applied to a reconsideration of literary farce sui generis, a genre represented in this article by a long-neglected work of utopian fiction, Archibald Marshall’s Upsidonia (1915). Although Upsidonia’s current disregard is arguably undeserved, the article’s chief interest is not to reclaim the novel on aesthetic (...) grounds but to illuminate the mechanics of what Marx would call its “serious buffoonery.” In its persistent reversal of capitalist principles and relations, Upsidonia naturally invites readers to revisit Marx, whose mordant gambit may serve as a key to Marshall’s own farcical plot and praxis, rooted in return and repetition, the essential maneuvers of farce itself. (shrink)

Normative theories suggest that inconsistencies be pointed out to the Decision Maker who is thus given the chance to modify his/her judgments. In this paper, we suggest that the inconsistencies problem be transferred from the Decision Maker to the Analyst. With the Mixture of Maximal Quasi Orders, rather than pointing out incoherences for the Decision Maker to change, these inconsistencies may be used as new source of information to model his/her preferences.

I describe two candidate representations of a mixture. The first, which I call the ‘standard representation’, is not a good representation of a mixture in spite of its widespread popularity. The second, which I call ‘Gibbs’ representation’, is less widely adopted but is, I argue, a much better representation. I show that, once we have a precise mathematical structure that can be used to represent thermodynamic systems, and once an adequate perspective on representation is adopted, Gibbs’ representation trumps (...) the standard representation. (shrink)

As is well known, Descartes’ doctrine on the relations of mind and body involves at least the following two theses: the real distinction of mind and body is compatible with their substantial union; and the siting of the mind at the tip of the pineal gland is compatible with its presence throughout the body. Th is essay seeks to perform three main tasks. One is to suggest that, so far as Descartes is concerned, the doctrine that arises out of the (...) combination of and blocks off the problems that are alleged to arise for mind-body interaction. A second is to illustrate how, in a certain vision of Descartes’ thought, and are more closely connected to each other than is generally explicitly recognised. And a third is to illustrate how one grade of mixture of stuff-types that the ancient Stoics envisaged both provides a model for answering Descartes’ demands and has a reputable pedigree within the tradition to which he was heir. (shrink)

This is a translation of Duhem's Le mixte et la combination chimique (1902) together with eight related essays including Les theories de la chaleur (1895), Thermochimie (1897), L'oeuvre de M. J. H. van 't Hoff (1900) and a short extract from Traité d'énergétique (1911) dealing with the nature of mixtures.

Inspired by recent progress in multi-agent Reinforcement Learning (RL), in this work we examine the collective intelligent behaviour of theoretical universal agents by introducing a weighted mixture operation. Given a weighted set of agents, their weighted mixture is a new agent whose expected total reward in any environment is the corresponding weighted average of the original agents' expected total rewards in that environment. Thus, if RL agent intelligence is quantified in terms of performance across environments, the weighted (...) class='Hi'>mixture's intelligence is the weighted average of the original agents' intelligences. This operation enables various interesting new theorems that shed light on the geometry of RL agent intelligence, namely: results about symmetries, convex agent-sets, and local extrema. We also show that any RL agent intelligence measure based on average performance across environments, subject to certain weak technical conditions, is identical (up to a constant factor) to performance within a single environment dependent on said intelligence measure. (shrink)

The Fully Bayesian Significance Test (FBST) is a coherent Bayesian significance test for sharp hypotheses. This paper proposes the FBST as a model selection tool for general mixture models, and compares its performance with Mclust, a model-based clustering software. The FBST robust performance strongly encourages further developments and investigations.

Robert Deltete and Anastasios Brenner have provided a thorough examination of my translation of Duhem’s Le mixte et la combinaison chimique (1902) and associated essays. I am very grateful for their efforts and gratified that such competent reviewers should be generally positive. They provide an overview of relevant aspects of Duhem’s life and work, which may serve to introduce him to readers of this journal and promote interest in Duhem studies. They also raise and answer some questions about the interpretation (...) and evaluation of Duhem’s work, make some points of criticism of my choice of material and question certain points of translation. The editor has suggested that I make a response, and I shall take up some issues in these three areas. Since Duhem’s views play a central role in the development of the concept of chemical substance which I have worked on in recent years, I will make several references to my own publications. (shrink)

Aristotle’s On generation and corruption raises a vital question: how is mixture, or what we would now call chemical combination, possible? It also offers an outline of a solution to the problem and a set of criteria that a successful solution must meet. Understanding Aristotle’s solution and developing a viable peripatetic theory of chemical combination has been a source of controversy over the last two millennia. We describe seven criteria a peripatetic theory of mixture must satisfy: uniformity, recoverability, (...) potentiality, equilibrium, alteration, incompleteness, and the ability to distinguish mixture from generation, corruption, juxtaposition, augmentation, and alteration. After surveying the theories of Philoponus , Avicenna , Averroes , and John M. Cooper , we argue for the merits of Richard Rufus of Cornwall’s theory. Rufus was a little known scholastic philosopher who became a Franciscan theologian in 1238, after teaching Aristotelian natural philosophy as a secular master in Paris. Lecturing on Aristotle’s De generatione et corruptione, around the year 1235, he offered his students a solution to the problem of mixture that we believe satisfies Aristotle’s seven criteria.Author Keywords: Mixture; Mixt; Chemical combination; Accidental potential; Potential; Elements; Medieval chemistry; Peripatetic chemistry; Aristotelian science; Richardus Rufus; Averroes ; Avicenna ; Philoponus ; John M. Cooper. (shrink)

Now with extra footnotes, by editorial demand! Final version accepted by Oxford Studies in Ancient Philosophy. -/- This essay consists in a trick and a potential insight. The trick consists in a minimalist interpretation of color mixture. The account of color mixture is minimalist in the sense that, given certain background assumptions, there is no more to Timaeus’ account of color mixture than the list of the chromatic pathēmata and the list of how these combine to elicit (...) perceptions of all the colors. The only potential controversial elements of the minimalist interpretation are the relevant background assumptions and the interpretation of the chromatic pathēmata. The potential insight concerns a motive that Plato, in the guise of Timaeus, may have for presenting an account of color mixture. Specifically, I shall argue that on the minimalist interpretation, Plato may be read as reconciling the Democritrean four color scheme with an older tradi- tion where white and black are the fundamental chromatic opposition. As we shall see, this bears on the interpretation of the chromatic pathēmata. (shrink)

Cet article démontre que le spectre d’une « intermédialité » ou d’une « transversalité » esthétique entre les arts verbaux et les arts « silencieux » est la source d’une angoisse profonde et la cause d’une polémique tenace dans la poétique gréco-romaine. À la ressemblance du discours aux arts « spatiaux » est attribuée continûment la corruption de vérité référentielle dans la littérature. Néanmoins, comme les interventions canoniques sur la question du visuel de Plutarque, Démétrios et Quintilien dans la littérature (...) le révèleront, ce rejet témoigne d’une inquiétude déplacée. Dans la capacité d’assouvir le monde temporel à l’œil de l’esprit au moyen de l’artifice, les arts spatiaux forment le miroir où le poétique reconnaît et refoule l’inventivité ontologique au cœur de la discursivité. Le fait que le dix-neuvième siècle marque la fin de la polémique classique contre la transversalité esthétique n’est pas contingent : la modernité esthétique est déterminée non seulement par une conciliation entre les arts mais également par une prise de possession consciente du potentiel ontologique du discours. (shrink)

The bulk of Duhem's writing which bears on the understanding of mixtures suggests he adopted an Aristotelian position which he opposed only to the atomic view. A third view from antiquity-that of the Stoics-seems not to be taken into account. But his lines of thought are not always as explicit as could be wished. The Stoic view is considered here from a perspective which Duhem might well have adopted. This provides a background against which his somewhat unorthodox Aristotelianism might be (...) understood. (shrink)

Aristotle’s On generation and corruption raises a vital question: how is mixture, or what we would now call chemical combination, possible? It also offers an outline of a solution to the problem and a set of criteria that a successful solution must meet. Understanding Aristotle’s solution and developing a viable peripatetic theory of chemical combination has been a source of controversy over the last two millennia. We describe seven criteria a peripatetic theory of mixture must satisfy: uniformity, recoverability, (...) potentiality, equilibrium, alteration, incompleteness, and the ability to distinguish mixture from generation, corruption, juxtaposition, augmentation, and alteration. After surveying the theories of Philoponus (d. 574), Avicenna(d. 1037), Averroes (d. 1198), and John M. Cooper (fl. circa2000), we argue for the merits of Richard Rufus of Cornwall’s theory. Rufus (fl. 1231–1256) was a little known scholastic philosopher who became a Franciscan theologian in 1238, after teaching Aristotelian natural philosophy as a secular master in Paris. Lecturing on Aristotle’s De generatione et corruptione, around the year 1235, he offered his students a solution to the problem of mixture that we believe satisfies Aristotle’s seven criteria. # 2004 Elsevier Ltd. All rights reserved. (shrink)

This volume sheds new light on Alexander of Aphrodisias' On Mixture and Growth as an intelligent and carefully crafted rebuttal of Stoic blending, which Alexander regarded as the closest rival of his own brand of hylomorphism. The authors explore Alexander's dialectical method and determine the precise character of the Stoic theory he attacks. The problematic notions of mutual co-extension and infinite division appear in their proper context, while the successive stages of the process of blending are carefully distinguished from (...) the resulting state of the blend. In this perspective the discussion of growth that closes Alexander's work finds its natural place. (shrink)

BACKGROUND -/- In biomedical ontologies, mereological relations have always been subject to special interest due to their high relevance in structural descriptions of anatomical entities, cells, and biomolecules. This paper investigates two important subrelations of has_proper_part, viz. the relation has_grain, which relates a collective entity to its multiply occurring uniform parts (e.g., water molecules in a portion of water), and the relation has_component, which relates a compound to its constituents (e.g., molecules to the atoms they consist of). -/- METHOD -/- (...) We distinguish between four kinds of complex entities and characterize them in first order logic. We then discuss whether similar characterizations could be given in description logics, and finally apply the results to mixtures. -/- RESULTS -/- At first sight, collectives and compounds seem to be disjoint categories. Their disjointness, however, relies on agreement about what are uniform entities, and thus on the granularity of description. For instance, the distinction between isomeric subtypes of a molecule can be important in one use case but might be neglected in another one. We demonstrate that, as implemented in the BioTop domain upper level ontology, equivalence or subsumption between different descriptions of same or similar entities cannot be achieved. Using OWL-DL, we propose a new design pattern that avoids primitive subrelations at the expense of more complex descriptions and thus supports the needed inferences. (shrink)

Mixture item response theory models include a mixture of latent subpopulations such that there are qualitative differences between subgroups but within each subpopulation the measure model based on a continuous latent variable holds. Under this modeling framework, students can be characterized by both their location on a continuous latent variable and by their latent class membership according to Students’ responses. It is important to identify anchor items for constructing a common scale between latent classes beforehand under the (...) class='Hi'>mixture IRT framework. Then, all model parameters across latent classes can be estimated on the common scale. In the study, we proposed Q-matrix anchored mixture Rasch model, including a Q-matrix and the traditional mixture Rasch model. The Q-matrix in QAMRM can use class invariant items to place all model parameter estimates from different latent classes on a common scale regardless of the ability distribution. A simulation study was conducted, and it was found that the estimated parameters of the QAMRM recovered fairly well. A real dataset from the Certificate of Proficiency in English was analyzed with the QAMRM, LCDM. It was found the QAMRM outperformed the LCDM in terms of model fit indices. (shrink)

The usual distinction in quantum mechanics between pure states and mixtures is shown not to be independent of the interpretation adopted. Thus, in a causal theory, certain states should be regarded as sharing the nature of both pure states and mixtures and, as a result, important questions in the theory of measurement must be considered in a different light.

Special issue of the Journal for Early Modern Studies (4.1., Spring 2005) Guest Editor: Lucian Petrescu. -/- .

In his introduction to part 2 of the Common Knowledge symposium on xenophilia, the journal's editor tours the reader through two private apartments and through two public art collections in an effort to establish that aesthetically coherent mixtures of apparently immiscible objects from widely divergent cultures are possible and also morally glamorous. Xenophobia at its least reprehensible, he argues, is a fear of ecumenism and its consequences, as well as a fear of one's own conversion — of “turning Turk.” Xenophilia (...) at its most admirable is a pursuit of coherent mixtures where others cannot imagine their possibility. Bits lifted from reputedly pure and organic wholes may be transformed by means of overlap and mediated juxtaposition into a novel milieu that has a wholeness, authenticity, and charisma of its own. Such coherence depends on minds that are capable of loving what does not satisfy their narcissism and that can sense in the products of their own culture elements or signs of enervation, anomie, lack, derangement, waywardness, rigidity, preciousness, or warping. The author concludes that xenophilia neither signals nor facilitates the adulteration that xenophobes so fear. (shrink)

The history of ancient chemistry has been virtually ignored. I examine the foundations of the chemical theories of the Peripatetics and Stoics, in an attempt to glean the motivations for their chemical theories, and how these theories relate to their greater natural philosophies. This involves a detailed examination of ancient theories of mixture. I attempt to relate Aristotle's theory of mixture to his theories of substantial change, the elements and matter. This entails a rejection of the notion of (...) prime matter, and a reevaluation of the status of the contrarieties. I also look at the understudied fourth book of the Meteorologica, which sheds new light on Aristotle's theory of matter. I then turn to Alexander of Aphrodisias, and his development of Aristotle's theory. Next I consider the Stoic theory of body, and how doxographers have misinterpreted this theory. While offering a radically new interpretation of the Stoic theory of mixture, much of Stoic natural philosophy is reconstructed, including their theory of categories and qualities. In the end a Stoic theory free from obvious paradox is presented. (shrink)

The following is an essay review of Paul Needham's translation of Pierre Duhem's Lemixte et la combinaison chimique and a numberof other essays. In this review we describe theintent and general features of Le mixte and try to place it in the larger context of Duhem'sprogram for energetics. The long essay (Essay3) opposing Marcellin Berthelot'sthermochemistry is singled out for detailedcommentary, since it gives Duhem's reasons forendorsing Josiah Willard Gibbs's chemicalstatics. We argue that a chemical mechanics ofa Gibbsian sort, defended in (...) Le mixte and otheressays in this volume, was the inspiration for,and basis of, Duhem's energetics. Needham'swelcome translations help an English-languageaudience to better understand the basiccontours of Duhem's important, if ultimatelymisguided, project. We conclude with somecomments on the difficulties in translatingDuhem and on the quality of the translationsNeedham has provided. (shrink)

seem to be a kind of corruption of the elements and not a mixture. Again, if the substantial form of a mixed body is the act of matter without presupposing the forms of simple bodies, then the simple bodies of the elements will lose their definition (rationem). For an element is that of which something is primarily composed, and exists in it and is indivisible ac-.