Different cell lineages growing in microgravity undergo a spontaneous transition leading to the emergence of two distinct phenotypes. By returning these populations in a normal gravitational field, the two phenotypes collapse, recovering their original configuration. In this review, we hypothesize that, once the gravitational constraint is removed, the system freely explores its phenotypic space, while, when in a gravitational field, cells are “constrained” to adopt only one favored configuration. We suggest that the genome allows for a wide range of “possibilities” (...) but it is unable per se to choose among them: the emergence of a specific phenotype is enabled by physical constraints that drive the system toward a preferred solution. These findings may help in understanding how cells and tissues behave in both development and cancer. In microgravity, cells undergo spontaneous and reversible transitions between different phenotypes. In the absence of physical constraints, living systems could yield bi-stable decisions. On the contrary, physical ‘boundaries’ constrain cells to acquire only a specific configuration by selecting and shaping different gene expression patterns provided by the intrinsic genetic stochasticity. (shrink)

In so-called ethorobotics and robot-supported social cognitive neurosciences, robots are used as scientific tools to study animal behavior and cognition. Building on previous epistemological analyses of biorobotics, in this article it is argued that these two research fields, widely differing from one another in the kinds of robots involved and in the research questions addressed, share a common methodology, which significantly differs from the “synthetic method” that, until recently, dominated biorobotics. The methodological novelty of this strategy, the research opportunities that (...) it opens, and the theoretical and technological challenges that it gives rise to, will be discussed with reference to the peculiarities of the two research fields. Some broad methodological issues related to the generalization of results concerning robot-animal interaction to theoretical conclusions on animal-animal interaction will be identified and discussed. (shrink)

The "myside bias'' in evaluating arguments is an empirically well-confirmed phenomenon that consists of overweighting arguments that endorse one's beliefs or attack alternative beliefs while underweighting arguments that attack one's beliefs or defend alternative beliefs. This paper makes two contributions: First, it proposes a probabilistic model that adequately captures three salient features of myside bias in argument evaluation. Second, it provides a Bayesian justification of this model, thus showing that myside bias has a rational Bayesian explanation under certain conditions.

Robots are being extensively used for the purpose of discovering and testing empirical hypotheses about biological sensorimotor mechanisms. We examine here methodological problems that have to be addressed in order to design and perform “good” experiments with these machine models. These problems notably concern the mapping of biological mechanism descriptions into robotic mechanism descriptions; the distinction between theoretically unconstrained “implementation details” and robotic features that carry a modeling weight; the role of preliminary calibration experiments; the monitoring of experimental environments for (...) disturbing factors that affect both modeling features and theoretically unconstrained implementation details of robots. Various assumptions that are gradually introduced in the process of setting up and performing these robotic experiments become integral parts of the background hypotheses that are needed to bring experimental observations to bear on biological mechanism descriptions. (shrink)

In their theoretical and experimental reflections on the capacities and behaviours of living systems, neuroscientists often formulate generalizations about the behaviour of neural circuits. These generalizations are highly idealized, as they omit reference to the myriads of conditions that could perturb the behaviour of the modelled system in real-world settings. This article analyses an experimental investigation of the behaviour of place cells in the rat hippocampus, in which highly idealized generalizations were tested by comparing predictions flowing from them with real-world (...) experimental results. The aim of the article is to identify under what conditions even single prediction failures regarding the behaviour of single cells sufficed to reject highly idealized generalizations, and under what conditions prima facie counter-examples were deemed to be irrelevant to the testing of highly idealized generalizations. The results of this analysis may contribute to understanding how idealized models are tested experimentally in neuroscience and used to make reliable predictions concerning living systems in real-world settings. (shrink)

Questo contributo tratta della perifrasi ‘εἶναι + participio’ in greco omerico all’interfaccia fra morfosintassi e semantica. I dati sono analizzati con riferimento al quadro teorico elaborato da Nardi e Romagno (2022), che considerano la perifrasi con εἶναι in greco antico come una categoria prototipica: secondo questa prospettiva, la categoria sovraordinata ‘εἶναι + participio’ include due manifestazioni formalmente diverse ma funzionalmente equivalenti, un costrutto con una copula espressa, cioè una perifrasi vera e propria, e un costrutto senza copula espressa, cioè un (...) participio predicativo (fondamentalmente, un participio che funziona come una forma finita). Questa indagine mira a valutare se si possano individuare fattori che determinano o soggiacciono all’uso di queste costruzioni participiali in greco omerico. L’analisi dei dati raccolti nei poemi omerici mostra che le costruzioni participiali codificano la funzione specifica di significare lo stato, inerente o acquisito, del soggetto del predicato, costituendo pertanto un’alternativa (più o meno libera) al perfetto originario (cfr. Romagno 2005). (shrink)

This book focuses on the relationship between different epistemological and theoretical advances in archaeology within different academic and philosophical traditions."--Publisher's web site.

Includes Spanish version of Vita Secundi (Life of Secundus of Athens) by Vincent of Beauvais, and the Spanish version (Castellana) by Walter Burley (Gualterus Burlaeus) with the Latin version in his "Tractatus de vita et moribus philosophorum et de quibusdam dictis eorum" from his ms. in the "Biblioteca Nacional de Madrid Vit. 18-7 (Olim T. 9), fols. 50r-51v"--See page 33.

What kinds of mental states are emotions? A common philosophical view says that they are episodic states. Some philosophers conceive of these states as bodily feelings or experiences of some sort, others as judgements or states very similar but not identical to judgements. I argue that emotions are not episodic states; like beliefs and desires, they are standing dispositional states that may manifest themselves in consciousness and behaviour. But emotions are neither beliefs nor desires; they are sui generis mental states. (...) We understand the nature of these states when we consider the role they play in ordinary folk-psychological explanations. (shrink)

The Somatic Mutation Theory has been challenged on its fundamentals by the Tissue Organization Field Theory of Carcinogenesis. However, a recent publication has questioned whether TOFT could be a valid alternative theory of carcinogenesis to that presented by SMT. Herein we critically review arguments supporting the irreducible opposition between the two theoretical approaches by highlighting differences regarding the philosophical, methodological and experimental approaches on which they respectively rely. We conclude that SMT has not explained carcinogenesis due to severe epistemological and (...) empirical shortcomings, while TOFT is gaining momentum. The main issue is actually to submit SMT to rigorous testing. This concern includes the imperatives to seek evidence for disproving one’s hypothesis, and to consider the whole, and not just selective evidence. (shrink)

We study, in an abstract and general framework, formal representations of dependence and groundedness which occur in semantic theories of truth. Our goals are: (a) to relate the different ways in which groundedness is defined according to the way dependence is represented; and (b) to represent different notions of dependence as instances of a suitable generalisation of the mathematical notion of functional dependence.

The advancement of computing technology makes it possible to build extremely accurate digital reconstructions of brain circuits. Are such unprecedented levels of biological accuracy essential for brain simulations to play the roles they are expected to play in neuroscientific research? The main goal of this paper is to clarify this question by distinguishing between various roles played by large-scale simulations in contemporary neuroscience, and by reflecting about what makes a simulation biologically accurate. It is argued that large-scale simulations may play (...) model-oriented and prediction-oriented roles in brain research, and that the concept of biological accuracy can be interpreted as related to the plausibility of the theoretical model implemented in the simulation system, to the accuracy of the computer implementation, and to the level of details of the implemented model. Building on these observations and distinctions, it is argued that biological accuracy is not essential for a computer simulation to play the epistemic roles it is expected to play in brain research. (shrink)

Revision sequences were introduced in 1982 by Herzberger and Gupta as a mathematical tool in formalising their respective theories of truth. Since then, revision has developed in a method of analysis of theoretical concepts with several applications in other areas of logic and philosophy. Revision sequences are usually formalised as ordinal-length sequences of objects of some sort. A common idea of revision process is shared by all revision theories but specific proposals can differ in the so-called limit rule, namely the (...) way they handle the limit stages of the process. The limit rules proposed by Herzberger and by Belnap show different mathematical properties, called periodicity and reflexivity, respectively. In this paper we isolate a notion of cofinally dependent limit rule, encompassing both Herzberger’s and Belnap’s ones, to study periodicity and reflexivity in a common framework and to contrast them both from a philosophical and from a mathematical point of view. We establish the equivalence of weak versions of these properties with the revision-theoretic notion of recurring hypothesis and draw from this fact some observations about the problem of choosing the “right” limit rule when performing a revision-theoretic analysis. (shrink)

Sometimes we speak of behaviours and actions as reactions, just as we speak of physical conditions and mental states as reactions. But what do we mean when we say that emotions are reactions? I answer this question by developing an account of emotions as psychological reactions to presentations or representations of states of affairs. I show that this account may provide a novel conceptual framework for explaining aspects of the intentionality, phenomenology and behavioural manifestation of emotions. I conclude by showing (...) that this account is compatible with the view that emotions can be assessed on grounds of justification and correctness. (shrink)

Human attention is limited in its capacity and duration. In language, this is manifested in many ways, but more conspicuously in the strategies by which information is distributed in utterances, that is, their information structures. We contend that the pragmatic categories of Topic and Presupposition precisely meet the necessity to modulate attentional resources on sentence contents, and they do this by “directing” certain contents to automatic and others to controlled processing mechanisms. We discuss experimental findings suggesting that presupposed or topicalized (...) information correlates with automatic processing, and we suggest that this association grounded for the emergence of topic and presupposition units in human communication. We also put forth the processing automaticity induced by these units as the rationale behind their persuasiveness in some specific contexts of language use. (shrink)

Simulation studies have been carried out in robotics for a variety of epistemic and practical purposes. Here it is argued that two broad classes of simulation studies can be identified in robotics research. The first one is exemplified by the use of robotic systems to acquire knowledge on living systems in so-called biorobotics, while the second class of studies is more distinctively connected to cases in which artificial systems are used to acquire knowledge about the behaviour of autonomous mobile robots. (...) The two classes pertain to sub-areas of robotics which are apparently quite distant from one another in terms of goals, methodologies, technologies, and theoretical backgrounds. Still both are concerned with building, running, and experimenting on simulations of other systems. This paper aims to reveal and discuss some methodological commonalities between the two classes of studies. Philosophical literature on simulation methodologies has been traditionally focused on studies carried out in research fields other than robotics: this article may therefore contribute to shedding light on how the concept of simulation is used in robotics, and on the role simulation methodologies play in this research field. (shrink)

The my-side bias is a well-documented cognitive bias in the evaluation of arguments, in which reasoners in a discussion tend to overvalue arguments that confirm their prior beliefs, while undervaluing arguments that attack their prior beliefs. The first part of this paper develops and justifies a Bayesian model of myside bias at the level of individual reasoning. In the second part, this Bayesian model is implemented in an agent-based model of group discussion among myside-biased agents. The agent-based model is then (...) used to perform a number of experiments with the objective to study whether the myside bias hinders or enhances the ability of groups to collectively track the truth, that is, to reach the correct answer to a given binary issue. An analysis of the results suggests the following: First, whether the truth-tracking ability of groups is helped or hindered by myside bias crucially depends on how the strength of myside bias is differentially distributed across subgroups of discussants holding different beliefs. Second, small groups are more likely to track the truth than larger groups, suggesting that increasing group size has a detrimental effect on collective truth-tracking through discussion. (shrink)

We examine the relationship between scientific knowledge and the legal system with a focus on the exclusion of expert testimony from trial as ruled by the Daubert standard in the US.We introduce a simple framework to understand and assess the role of judges as “gatekeepers”, monitoring the admission of science in the courtroom. We show how judges face a crucial choice, namely, whether to limit Daubert assessment to the abstract reliability of the methods used by the expert witness or also (...) to check whether the application of those methods was correct. Undesirable outcomes result from both choices, thereby giving rise to the “gatekeeper’s dilemma.” We illustrate the dilemma by analyzing in some detail two well-known cases of Daubert challenges to economic experts. Finally, we present reasons for the absence of straightforward solutions to the dilemma and for its likely endurance. (shrink)

In recent decades, the analysis of phraseology has made use of the exploration of large corpora as a source of quantitative information about language. This paper intends to present the main lines of work in progress based on this empirical approach to linguistic analysis. In particular, we focus our attention on some problems relating to the morpho-syntactic annotation of corpora. The CORIS/CODIS corpus of contemporary written Italian, developed at CILTA – University of Bologna (Rossini Favretti 2000; Rossini Favretti, Tamburini, De (...) Santis in press), is a synchronic 100-million-word corpus and is being lemmatised and annotated with part-of-speech (POS) tags, in order to increase the quantity of information and improve data retrieval procedures (Tamburini 2000). The aim of POS tagging is to assign each lexical unit to the appropriate word class. Usually the set of tags is pre-established by the linguist, who uses his/her competence to identify the different word classes. The very first experiments we made revealed how the traditional part-of-speech distinctions in Italian (generally based on morphological and semantic criteria) are often inadequate to represent the syntactic features of words in context. It is worth noting that the uncertainties in categorisation contained in Italian grammars and dictionaries reflect a growing difficulty as they move from fundamental linguistic classes, such as nouns and verbs, to more complex classes, such as adverbs, pronouns, prepositions and conjunctions. This latter class, that groups together elements traditionally used to express connections between sentences, appears inadequate when describing cohesive relations in Italian. This phenomenon actually seems to involve other elements traditionally assigned to different classes, such as adverbs, pronouns and interjections. Recent studies proposed the class of ‘connectives’, grouping all words that, apart from their traditional word class, have the function of connecting phrases and contributing to textual cohesion. From this point of view, conjunctions can be considered as part of phrasal connectives, that can in turn be included in the wider category of textual connectives. The aim of this study is to identify elements that can be included in the class of phrasal connectives, using quantitative methods. According to Shannon and Weaver’s (1949) observation that words are linked by dependent probabilities, corroborated by Halliday’s (1991) argument that the grammatical “system” (in Firth’s sense of the term) is essentially probabilistic, quantitative data are introduced in order to provide evidence of relative frequencies. Section 2 presents a description of word-class categorisation from the point of view of grammars and dictionaries arguing that the traditional category of conjunctions is inadequate for capturing the notion of phrasal connective. Section 3 examines the notion of ‘connective’ and suggests a truth-function interpretation of connective behaviour. Section 4 describes the quantitative methods proposed for analysing the distributional properties of lexical units, and section 5 comments on the results obtained by applying such methods drawing some provisional conclusions. (shrink)

The model of self-referential truth presented in this paper, named Revision-theoretic supervaluation, aims to incorporate the philosophical insights of Gupta and Belnap’s Revision Theory of Truth into the formal framework of Kripkean fixed-point semantics. In Kripke-style theories the final set of grounded true sentences can be reached from below along a strictly increasing sequence of sets of grounded true sentences: in this sense, each stage of the construction can be viewed as an improvement on the previous ones. I want to (...) do something similar replacing the Kripkean sets of grounded true sentences with revision-theoretic sets of stable true sentences. This can be done by defining a monotone operator through a variant of van Fraassen’s supervaluation scheme which is simply based on ω-length iterations of the Tarskian operator. Clearly, all virtues of Kripke-style theories are preserved, and we can also prove that the resulting set of “grounded” true sentences shares some nice features with the sets of stable true sentences which are provided by the usual ways of formalising revision. What is expected is that a clearer philosophical content could be associated to this way of doing revision; hopefully, a content directly linked with the insights underlying finite revision processes. (shrink)

This paper introduces a comprehensive logical framework to reason about threshold-driven diffusion and threshold-driven link change in social networks. It considers both monotonic dynamics, where agents can only adopt new features and create new connections, and non-monotonic dynamics, where agents may also abandon features or cut ties. Three types of operators are combined: one capturing diffusion only, one capturing link change only, and one capturing both at the same time. We first characterise the models on which diffusion of a unique (...) feature and link change stabilise, whilst discussing salient properties of stable models with multiple spreading features. Second, we show that our operators (and any combination of them) are irreplaceable, in the sense that the sequences of model updates expressed by a combination of operators cannot always be expressed using any other operators. Finally, we analyse classes of models on which some operators can be replaced. (shrink)

BackgroundThe present study aimed at assessing the diagnostic properties of the Montreal Cognitive Assessment in non-demented ALS patients and at exploring the MoCA administrability according to motor-functional status.MaterialsN = 348 patients were administered the MoCA and Edinburgh Cognitive and Behavioural ALS Screen. Administrability rates and prevalence of defective MoCA scores were compared across King’s and Milano-Torino clinical stages. Regression models were run to test whether the non-administrability of the MoCA and a defective score on it were predicted, net of the (...) ECAS-Total, by disease duration, ALS Functional Rating Scale-Revised and progression rate, computed as /disease duration. Intrinsic and post-test diagnostics were tested against a below-cut-off ECAS-total score.ResultsThe 79.9% of patients successfully underwent the MoCA, whose administrability rates decreased with advanced clinical stages, at variance with its defective score prevalence. The probability of the FAB not being administrable was predicted only by lower ALSFRS-R-bulbar and-upper-limb scores; no motor features, but the ECAS-Total, predicted a defective MoCA performance. The MoCA showed high accuracy and good intrinsic and post-test properties—being slightly more specific than sensitive.DiscussionIn non-demented ALS patients, the MoCA is featured by optimal diagnostics as a screener for cognitive impairment, especially for ruling-out its occurrence, as long as patients are in the early stages of the disease and have sufficiently spared bulbar and upper-limb functions. (shrink)

BackgroundThis study aimed at standardizing and providing preliminary evidence on the clinical usability of the Italian telephone-based Verbal Fluency Battery, which includes phonemic, semantic and alternate verbal fluency tasks.MethodsThree-hundred and thirty-five Italian healthy participants and 27 individuals with neurodegenerative or cerebrovascular diseases were administered the t-VFB. Switch number and cluster size were computed via latent semantic analyses. HPs underwent the telephone-based Mental State Examination and Backward Digit Span. Construct validity, factorial structure, internal consistency, test-retest and inter-rater reliability and equivalence with (...) the in-person Verbal Fluency tasks were assessed. Norms were derived via Equivalent Scores. Diagnostic accuracy against clinical populations was assessed.ResultsThe majority of t-VFB scores correlated among each other and with the BDS, but not with the MMSE. Switch number correlated with t-PVF, t-SVF, t-AVF scores, whilst cluster size with the t-SVF and t-AVF scores only. The t-VFB was underpinned by a mono-component structure and was internally consistent. Test-retest and inter-rater reliability were optimal. Each t-VFB test was statistically equivalent to its in-person version. Education predicted all t-VFB scores, whereas age t-SVF and t-AVF scores and sex only some t-SVF scores. Diagnostic accuracy against clinical samples was optimal.DiscussionThe t-VFB is a valid, reliable and normed telephone-based assessment tool for language and executive functioning, equivalent to the in-person version; results show promising evidence of its diagnostic accuracy in neurological populations. (shrink)

Summary My paper aims to clarify the subsequent steps of Rome’s encroachment on Etruria in the aftermath of the Pyrrhic War. As is well known, the Latin colony of Cosa was founded in 273 BC on the Tyrrhenian coast to the north of Vulci; moreover, in the years 264–245 BC, four citizen colonies were founded on the Caeretan coast, namely Castrum Novum, Pyrgi, Alsium and Fregenae. Unfortunately, it is not easy to reconstruct precisely what the Roman movements in Etruria were, (...) or how the Etruscans reacted to them. Above all, it is difficult to determine whether a colonial foundation like Cosa – which was contemporary with the establishment of Paestum in Lucania – was part of a broader and coherent strategy that the Romans had been following in their expansion into the Italian peninsula. By evaluating all the available evidence, I will try to demonstrate that the foundation of Cosa depended more upon particular contingencies than upon any preconceived plan for the conquest of Italy. (shrink)

This article outlines the constitution of a disciplinary field called ‘philosophy of design’. The roots of this philosophical branch can be traced back to the one of the first theoretical consideration about the “sciences of the artificial” (Simon 1996 [1969]) – which in opposition to natural sciences should deal with non-natural entities which populates our world, namely artifacts. These considerations have been extended and discussed starting from a research program aimed at changing the route within philosophy of technology: the so (...) called “empirical turn in philosophy of technology” (Kroes, Meijers 2000). Following this, two issues have been debated in the subsequent years: the first is related to the definition of ‘design’ and to the philosophical questions that arise (like the reference of design terms and their truth-value); the second is a problem of demarcation between science and design (are these two activities different?). The aim of the article is presenting an overview of the debate and showing some possible future developments for the philosophy of design. (shrink)

Uno dei principali meriti del libro di Pietro Perconti è l’aver fatto chiarezza su una dimensione così elusiva e complicata come il senso comune, precisandone in modo perspicuo i tratti oppositivi e di continuità che ne contraddistinguono le relazioni con gli acquisti teorici della scienza cognitiva e le loro ricadute pratiche. Quest’obiettivo è raggiunto grazie anche alle risorse di una scrittura incisiva e scorrevole, che ottempera alle esigenze dell’alta divulgazione senza che ne sia intac...

This thesis addresses two questions. One concerns the metaphysics of emotions and asks what kinds of mental states emotions are. The other asks how the metaphysics of emotions bears on first and third-personal knowledge of emotions. There are two prevailing views on the nature of emotions. They are the perception and cognitive views. The perception view argues that emotions are bodily feelings. The cognitive view, by contrast, contends that emotions are some sorts of evaluative judgments. I show that both views (...) provide inadequate accounts of the nature of emotions. The perception view fails to do justice to the fact that emotions may not involve any bodily feeling. The cognitive view, by contrast, cannot account for the fact that emotions are states that adult humans have in common with infants and animals. On the basis of these criticisms, I put forward an alternative account of emotions. This involves five main arguments. The first is that emotions are enduring non-episodic dispositions that may or may not manifest themselves in experiential episodes such as emotional feelings and behaviour episodes such as expressions. The second argument is that emotional feelings are perceptions of specific bodily changes brought about by emotions. These feelings serve as clues as to what kinds of emotions the subject has. The third argument is that expressions are observable manifestations of emotions in virtue of which emotions can be perceived and subsequently known, directly and non-inferentially, by other people. The fourth argument is that when someone has an emotion without feeling it, she can still come to know it by believing true ascriptions that other people make about the emotion they perceive in her expression. The fifth argument is that full knowledge of emotions requires knowledge of the emotion objects. (shrink)

This paper studies an argument in the prologue of the Charmides which defends the view that it is impossible to cure the body independently of the soul. I argue that Socrates is committed to an account of the psychē as an embodied soul, causally responsible for the biological condition of the body. Furthermore, the prescription of kaloi logoi as a treatment for the soul’s biological failures suggests that Socrates appears to initially regard the ethical and biological dimensions of the soul (...) as intimately connected. But I also show that Socrates is unable to maintain this position consistently throughout the passage. A similar conflation of functions can be traced in R. X.608d–611a. (shrink)

The significance of consciousness in modern science is discussed by leading authorities from a variety of disciplines. Presenting a wide-ranging survey of current thinking on this important topic, the contributors address such issues as the status of different aspects of consciousness; the criteria for using the concept of consciousness and identifying instances of it; the basis of consciousness in functional brain organization; the relationship between different levels of theoretical discourse; and the functions of consciousness.

In the past decades, an enormous amount of precious information has been collected about molecular and genetic characteristics of cancer. This knowledge is mainly based on a reductionistic approach, meanwhile cancer is widely recognized to be a ‘system biology disease’. The behavior of complex physiological processes cannot be understood simply by knowing how the parts work in isolation. There is not solely a matter how to integrate all available knowledge in such a way that we can still deal with complexity, (...) but we must be aware that a deeply transformation of the currently accepted oncologic paradigm is urgently needed. We have to think in terms of biological networks: understanding of complex functions may in fact be impossible without taking into consideration influences outside of the genome. Systems Biology involves connecting experimental unsupervised multivariate data to mathematical and computational approach than can simulate biologic systems for hypothesis testing or that can account for what it is not known from high-throughput data sets. Metabolomics could establish the requested link between genotype and phenotype, providing informations that ensure an integrated understanding of pathogenic mechanisms and metabolic phenotypes and provide a screening tool for new targeted drug. (shrink)

What can interactive robots offer to the study of social behaviour? Philosophical reflections about the use of robotic models in animal research have focused so far on methods involving robots which do not interact with the target system. Yet, leading researchers have claimed that interactive robots may constitute powerful experimental tools to study collective behaviour. Can they live up to these epistemic expectations? This question is addressed here by focusing on a particular experimental methodology involving interactive robots which has been (...) often adopted in animal research. This methodology is shown to differ from other robot-supported methods for the study of animal behaviour analysed in the philosophical literature, chiefly including the synthetic method. It is also discussed whether biomimicry and acceptability are necessary for an interactive robot to be sensibly used in animal research according to this method. (shrink)

Revision sequences are a kind of transfinite sequences which were introduced by Herzberger and Gupta in 1982 as the main mathematical tool for developing their respective revision theories of truth. We generalise revision sequences to the notion of cofinally invariant sequences, showing that several known facts about Herzberger’s and Gupta’s theories also hold for this more abstract kind of sequences and providing new and more informative proofs of the old results.