Artículos Ciudadanía y sociedad civil en las democracias contemporáneas. Citizenship and civil society in contemporary democracies. de La Vega, Marta El poder simbólico de los medios de comunicación.The transformations of the political in the field of the symbolic.González Broquen, Ximena La rutinizacion de la indiferencia ética y el aplanamiento de los valores en la Argentina actual. Ethical indifference routine and smoothing moral in contemporary Argentine. Meabe, Joaquín E. Jürgen Habermas: entre la ética del discurso y la ética de la (...) especie. Jürgen Habermas: between the ethics of discourse and the ethics of the species. Moreno Lax, Alejandro Derechos humanos y proceso justo.Human rights and rightful process. Ramos Pascua, José Antonio El Fedón o la trascendencia del alma.Phaedo or the inmortality of the soul. Robledo Rodriguez, Alejandro La enseñanza del derecho en los países de derecho escrito.Legal education in civil law systems. Rodríguez Ferrara, Mauricio De cómo los latinoamericanos percibimos la pena de muerte. How latin-americans view the death penalti. Rodríguez Ferrara, Mauricio La doctrina platónica del alma en el 'Timeo'.The platonic doctrine of soul in 'Thimaeus'. Suzzarini, Andrés Interdisciplinares Bajo los murmullos: tributo a Juan Rulfo. Under the whispers: a homage to Juan Rulfo. Camacho Crispín, Marco Antonio Recensiones Semblanza del jurista venezolano Tulio Chiossone. Belandria, Margarita Informaciones Índice acumulado. (shrink)

Artículos Ciudadanía y sociedad civil en las democracias contemporáneas. Citizenship and civil society in contemporary democracies. de La Vega, Marta El poder simbólico de los medios de comunicación.The transformations of the political in the field of the symbolic.González Broquen, Ximena La rutinizacion de la indiferencia ética y el aplanamiento de los valores en la Argentina actual. Ethical indifference routine and smoothing moral in contemporary Argentine. Meabe, Joaquín E. Jürgen Habermas: entre la ética del discurso y la ética de la (...) especie. Jürgen Habermas: between the ethics of discourse and the ethics of the species. Moreno Lax, Alejandro Derechos humanos y proceso justo.Human rights and rightful process. Ramos Pascua, José Antonio El Fedón o la trascendencia del alma.Phaedo or the inmortality of the soul. Robledo Rodriguez, Alejandro La enseñanza del derecho en los países de derecho escrito.Legal education in civil law systems. Rodríguez Ferrara, Mauricio De cómo los latinoamericanos percibimos la pena de muerte. How latin-americans view the death penalti. Rodríguez Ferrara, Mauricio La doctrina platónica del alma en el 'Timeo'.The platonic doctrine of soul in 'Thimaeus'. Suzzarini, Andrés Interdisciplinares Bajo los murmullos: tributo a Juan Rulfo. Under the whispers: a homage to Juan Rulfo. Camacho Crispín, Marco Antonio Recensiones Semblanza del jurista venezolano Tulio Chiossone. Belandria, Margarita Informaciones Índice acumulado. (shrink)

Artículos Ciudadanía y sociedad civil en las democracias contemporáneas. Citizenship and civil society in contemporary democracies. de La Vega, Marta El poder simbólico de los medios de comunicación.The transformations of the political in the field of the symbolic.González Broquen, Ximena La rutinizacion de la indiferencia ética y el aplanamiento de los valores en la Argentina actual. Ethical indifference routine and smoothing moral in contemporary Argentine. Meabe, Joaquín E. Jürgen Habermas: entre la ética del discurso y la ética de la (...) especie. Jürgen Habermas: between the ethics of discourse and the ethics of the species. Moreno Lax, Alejandro Derechos humanos y proceso justo.Human rights and rightful process. Ramos Pascua, José Antonio El Fedón o la trascendencia del alma.Phaedo or the inmortality of the soul. Robledo Rodriguez, Alejandro La enseñanza del derecho en los países de derecho escrito.Legal education in civil law systems. Rodríguez Ferrara, Mauricio De cómo los latinoamericanos percibimos la pena de muerte. How latin-americans view the death penalti. Rodríguez Ferrara, Mauricio La doctrina platónica del alma en el 'Timeo'.The platonic doctrine of soul in 'Thimaeus'. Suzzarini, Andrés Interdisciplinares Bajo los murmullos: tributo a Juan Rulfo. Under the whispers: a homage to Juan Rulfo. Camacho Crispín, Marco Antonio Recensiones Semblanza del jurista venezolano Tulio Chiossone. Belandria, Margarita Informaciones Índice acumulado. (shrink)

In our everyday interaction with the environment, we often perceive objects and spaces as opportunities to feel, maintain, enhance, and change our affective states and processes. The concept of affective affordance was coined to accommodate this aspect of ordinary perception and the many ways in which we rely on the material environment to regulate our emo- tions. One natural way to think of affective affordances in emotion regulation is to interpret them as tools for regulating felt affective states. We argue (...) that this way of conceiving of affective affordances is too restrictive. By analyzing the role of expressive properties of objects and spaces in emotion regulation, we show that our environment does not need to elicit felt affective states to regulate our emotions. Thus, we revise the concept of affective affordance to accommodate these cases. This revised concept explains more with less. Hence, it should be preferred in wide-reaching philosophical projects that aim to explain human affectivity as a situated phenomenon. (shrink)

This chapter describes the concept of enactive memory, which is quite new but increasingly discussed in contemporary philosophy of memory. Although the enactive approach has been used to investigate several memory sys- tems, e.g., procedural memory, episodic mem- ory, and autobiographical memory, this chapter focuses only on the enactive approach to epi- sodic memory because most of the current debate on enactive memory is about this mem- ory system. Section “Introduction” specifies what type of enactive memory is discussed in this (...) chapter. Section “The Concept of Enactive Memory” introduces the concept of enactive memory, clarifies its central theoretical com- mitments and goals, and describes how enactivists have explained episodic remember- ing. Section “The Philosophical Context of Enactive Memory” provides a brief contextu- alization of the enactive approach to memory with respect to approaches and theories with which, for one reason or another, it shares some theoretical insights, like the embodied, the extended, and the distributed approach, and the simulation theory. Section “Forgetting as a Challenge for Enactive Memory” explains why forgetting poses an important explanatory challenge to the enactive approach to memory and describes one philosophical proposal that has been developed to address this challenge. Section “Summary” provides a summary of the chapter, mentions some ongoing projects on enactive memory, and identifies some topics that advocates of the enactive approach to memory may want to investigate in the future. (shrink)

This introduction presents a state of the art of philosophical research on cognitive phenomenology and its relation to the nature of conscious thinking more generally. We firstly introduce the question of cognitive phenomenology, the motivation for the debate, and situate the discussion within the fields of philosophy, cognitive psychology and consciousness studies. Secondly, we review the main research on the question, which we argue has so far situated the cognitive phenomenology debate around the following topics and arguments: phenomenal contrast, epistemic (...) arguments and challenges, introspection, ontology and temporal character, intentionality, inner speech, agency, holistic perspective, categorical perception, value, and phenomenological description. Thirdly, we suggest future developments by pointing to four questions that can be explored in relation to the cognitive phenomenology discussion: the self and self-awareness, attention, emotions and general the... (shrink)

BackgroundThis study aims to quantitatively and qualitatively evaluate the activities of a Bioethics Unit (BU) 5 years since its implementation (2016–2020). The BU is a research unit providing empirical research on ethical issues related to clinical practice, clinical ethics consultation, and ethical education for health care professionals (HPS).MethodsWe performed an explanatory, sequential, mixed-method, observational study, using the subsequent qualitative data to explain the initial quantitative findings. Quantitative data were collected from an internal database and analyzed by descriptive analysis. Qualitative evaluation (...) was performed by semi-structured interviews with 18 HPs who were differently involved in the BU’s activities and analyzed by framework analysis.ResultsQuantitative results showed an extensive increment of the number of BU research projects over the years and the number of work collaborations with other units and wards. Qualitative findings revealed four main themes, concerning: 1. the reasons for contacting the BU and the type of collaboration; 2. the role of the bioethicist; 3. the impact of BU activities on HPs, in terms of developing deeper and more mature thinking; 4. the need to extend ethics support to other settings. Overall, our results showed that performing both empirical bioethics research and more traditional clinical ethics activities at the same unit would produce an impetus to increase collaboration and spread an 'ethical culture' among local HPs.ConclusionsOur findings contribute to a growing body of literature on the models of clinical ethics support services and the role of empirical research in bioethics internationally. They also prepare the ground for the implementation of a multidisciplinary Clinical Ethics Committee (CEC) that aims to support the BU’s ethics consultation service within the local context. (shrink)

While inanimate objects can neither experience nor express emotions, in principle they can be expressive of emotions. In particular, music is a paradigmatic example of something expressive of emotions that surely cannot feel anything at all. The Contour theory accounts for music expressiveness in terms of those resemblances that hold between its external and perceivable properties and the typical contour of human emotional behavior. Provided that some critical aspects are emended – notably, the stress on the perception of similarity instead (...) of the more plausible hypothesis that the listener perceives manifestations that are similar – we are inclined to endorse contour theory. In particular, we share its basic idea that expressive properties are perceived. Although other kinds of processes – high-level conceptual inferences, imagination – sometimes characterize our encounters with music, still perception constitutes the standard process underlying the detection of expressiveness. Moreover, we propose to extend contour theory to visual arts. Taking into consideration, as a case study, depicted landscapes, we observe that they frequently cannot but express emotions such as joy, sadness, liveliness or melancholy. The fact that pictures, unlike music, lack any temporal dimension is a prima facie reason for doubting the extendibility of contour theory’s conceptual arsenal to them. Nevertheless, while being obviously unable to behave somehow, we claim that depicted landscapes can perfectly convey dynamic information. If this is the case, the extension of the notion of contour to visuals art via the stress on the notion of dynamism would represent a second interesting revision of contour theory. (shrink)

This book provides a critical reflection on automated science and addresses the question whether the computational tools we developed in last decades are changing the way we humans do science. More concretely: Can machines replace scientists in crucial aspects of scientific practice? The contributors to this book rethink and refine some of the main concepts by which science is understood, drawing a fascinating picture of the developments we expect over the next decades of human-machine co-evolution. The volume covers examples from (...) various fields and areas, such as molecular biology, climate modeling, clinical medicine, and artificial intelligence. The explosion of technological tools and drivers for scientific research calls for a renewed understanding of the human character of science. This book aims precisely to contribute to such a renewed understanding of science. (shrink)

En este artículo nos proponemos reconstruir las bases de la teoría política calviniana. Intentaremos comprender cómo define el reformador al sujeto político de su teología, donde es definido como Pueblo de Dios. A través de una Teología de la Alianza Calvino establece los términos de un contrato político en el que las instituciones humanas son queridas y establecidas por Dios. A continuación, veremos que el Estado cristiano según Calvino es la plataforma desde la que se promueve el conocimiento de la (...) Voluntad divina, a través de la predicación y la positivación de leyes conformes a la misma. Finalmente, veremos que las ideas del reformador sobre la organización y la naturaleza de la política tuvieron en Ginebra una realización evidente. Ni sus textos ni sus acciones nos permiten calificar a Calvino de constitucionalista o republicano, sino más bien de hombre de orden y defensor de la tradición del derecho divino de los reyes. (shrink)

In our contemporary age, where a combination of individualism and mutual distrust is unhappily common among people and society is “liquid” and disoriented, so-called intermediate units are a precious resource that promotes positive coexistence within organizations and in local communities, too. The present contribution describes an example of such an intermediate unit, the Talent Club, located in a peripheral neighborhood of a metropolitan area in northern Italy. This case study shows the development of positive living and working together in organizations (...) and their transformation in the tool for community development and good coexistence. Qualitative and quantitative data show that the relational aspect is crucial because it promotes authentic exchange among people, supporting participation and social cohesion against self-referential habits and isolation. Although at present the Talent Club is mostly functioning in a affiliating coexistence among members, seeds of a more generativ... (shrink)

Dans cet aperçu, la notion de corps, qui joue un rôle majeur dans la théologie de l’Aquinate, de la création à l’eschatologie, est étudiée dans une perspective philosophique. Les différents sens que Thomas attribue au mot « corps » sont notamment caractérisés, selon qu’il se réfère aux réalités extra-mentales ou à notre manière d’en comprendre et d’en analyser la structure. S’inspirant d’Aristote et Porphyre d’un côté, d’Avicenne de l’autre, Thomas distingue ainsi non seulement entre le corps en tant qu’accident quantitatif (...) et en tant que détermination substantielle, mais aussi entre le corps pris en tant que partie d’un être corporel et en tant que tout. Parmi d’autres aspects, la relation que le corps entretient avec la matière est précisée. (shrink)

In this paper, I will investigate the notion of mind within the “Extended Mind” theory, as it is defended by Andy Clark. The aim is to provide an explanation of its key ideas and to highlight some of its consequences. In the first part I will briefly explain the main features of Clark's theory. In the second part, I will discuss his account of the nature of language and its relationship to cognition, and I will relate it with the arguments (...) for cognitive and mental extension. Then I will use my analysis of Clark's arguments in order to individuate some problems, which characterize his philosophical position. Although I am sympathetic with his theory, I will argue that it is nonetheless committed to a narrow account of cognition and mind. For this reason, I will propose a way to integrate Clark's theory within a semiotic and pragmatist framework inspired by C.S. Peirce. I suggest that, if we conceive the cognition as a semiotic sense-making process, we can provide a broad account of cognition and a fully externalist position about the mind. (shrink)

In this paper, I will discuss what the first phases of the long history of the transformation of Political in the Spiritual patria consisted of and those who made the development possible. In this essay the main protagonists will be Cicero and Saint Augustine. We will see how St. Augustine could complete the transformation of Cicero's political ideal not only theoretically but practically. St. Augustine's great work can be understood to be a replica of Cicero's Republic in which the City (...) of God is made into the Dream of Scipio and the Church occupies the place of the res publica. The theologizing of the political concepts is taken from the modernization process which Schmitt defined as illegitimate politics of the process of secularization of theoretical concepts. (shrink)

Carl Schmitt suele ser considerado un crítico de la modernidad por sostener que los principales conceptos de la teoría del Estado son conceptos teológicos secularizados. En este trabajo pretendemos poner de manifiesto que la importancia que Schmitt concede a la teología es aún mayor. En efecto, la secularización se refiere a los conceptos claves de la teoría del Estado, pero la política es previa al Estado. Y para establecer sus categorías, Schmitt se sirve de la teología: el carácter conflictivo o (...) pacífico del hombre remite al pecado original; el dilema amigo/enemigo a la elección entre Dios y el diablo, etc. Exploraremos el.alcance de estas analogías, intentando mostrar el carácter inerradicablemente teológico del pensamiento de Schmitt. (shrink)

Caracterización de un grupo de comités de ética en investigación en Colombia Caracterização de um grupo de comitês de ética em pesquisa na Colômbia In the last decades, controlled clinical trials sponsored by the pharmaceutical industry have increased considerably. This has led to the need for greater control and assistance by regulators and ethics committees to ensure appropriate compliance with established ethical standards and good clinical practices in general. In Colombia, the National Food and Drug Surveillance Institute, the regulator in (...) the country, controls and monitors the operation of clinical research with drugs. In 2008, this entity issued Resolution 2378, which provides and regulates research actors in Colombia, including ethics committees. After being in force for several years, it is necessary to know whether research ethics committees in Colombia operate in accordance with this regulation and to determine the status of implementation of the requirements therein. For this purpose, a survey was designed to be voluntarily answered and a response was obtained from 25 of the 69 certified committees in Colombia. Twenty-two of them could be analyzed because their information was complete. Compared with previous studies, favorable changes in development and organization were observed in accordance with the current proposed regulation. Para citar este artículo / To reference this article / Para citar este artigo Suárez-Obando F, Reynales H, Urina M, Camacho J, Viteri M. Caracterización de un grupo de comités de ética en investigación en Colombia. pers. bioét. 2018; 22: 303-318. DOI: 10.5294/pebi.2018.22.2.8. (shrink)

In this paper, I will look at two passages from the discussion of education in Book VII of Plato’s Republic: 523b-524d and 537e-539d. These passages, when taken together, present a puzzle for the coherency of the educational programme Socrates describes. Both discuss contradiction. One says that contradiction is educationally edifying, the other, that it is corrupting. This sounds like a contradiction about contradiction. As far as I know, no one has noticed this puzzle before. By the end of this paper, (...) I hope to have not only provided a solution to the apparent contradiction about contradiction that is compelling, but also one that shows that this puzzle, which might at first have seemed restricted to a textual issue about the educational programme in the Republic, is in fact one that has far reaching implications for a range of Plato’s theories across several dialogues. Along with education, corruption, and contradiction, I will discuss Plato’s theory of psychology, and his theory of forms. (shrink)

Health behaviours of preschool children have a considerable impact on the shaping of habits later on in their lives. Parents’ and guardians’ role is to develop positive health patterns and represent exemplary models to be followed by children. The aim of the paper is to present the use of correspondence analysis for the assessment of the relationship between eating habits of parents and children, as well as for the determination of the most common situations in which preschool children consume fast-food (...) products and to find the relationship between the frequency of fast-food consumption and BMI values in preschool children. The tests were carried out with the use of an own survey carried out in kindergartens in Białystok among parents dropping off and picking up children. 149 correctly filled questionnaires were obtained. The statistical analysis employs the chi-squared test and correspondence analysis. Among the tested children, a statistically significant relationship between body weight and sex was obtained. In the group of children and parents consuming fast-foods, a statistically significant relationship between the frequency of children’s and parents’ consumption of the products in question was noticed. A statistically significant relationship between the age of introduction of fast-food products into the child’s diet and their BMI was found. A situation that was statistically significant as far as contribution to frequent consumption of fast-food products by children, i.e. at least once a week, were children and parents shopping together. The relationship between the frequency of fast-food consumption by parents and children was presented in the form of correspondence maps, as well as the relationship between the child’s BMI and the age when the first fast-food product is served, and the relationship between the child’s BMI and the frequency of their consumption of fast-foods. Unfortunately, despite the high awareness among parents of the harmful effects of fast-food products and the widespread health education programmes, a number of the children in kindergartens were overweight or even obese. For this reason, the quality of the educational programmes in kindergartens, as well as in various media outlets, needs to be improved, with emphasis put on their effectiveness, in order to minimise the problem of the occurrence of overweight and obesity in children. It is also important for parents rearing children to pay special attention not only to their children’s menus, but also to foods consumed in the presence of children. (shrink)

In contrast to many countries, the political debates in the Netherlands on reproductive technologies and embryo research have paid particular attention to the issue of health risks to women. This article focuses on the question to what extent the discourse of gender has contributed to shaping the space for embryonic research in this country. The author argues that in the policy arena flexible conceptualizations of risks and burdens to women and of the identities of embryos have been crucial in drawing (...) and maintaining a discursive boundary between the domains of medically assisted reproduction and embryo research. The author shows that feminist intervention challenging this discursive strategy has had an impact on the present regulation of research. However, the main weakness of this temporary and partial feminist success is the virtual absence of a public debate on the meaning and desirability of embryo research. (shrink)

An elderly patient in his early eighties is hospitalized in a long-term facility, with advanced Alzheimer disease. He is otherwise relatively strong and free from other life-threatening conditions, except for the fact that he has difficulties swallowing. After several episodes of acute aspiration pneumonia doctors prescribe “strict fast”: only hydration through an IV catheter should be administered during the night, in order to relieve the feeling of hunger, provide comfort, and stave off death. The patient is surrounded by a warm (...) and extremely close-knit Mediterranean family. His wife and six adult children take turns feeding him properly mixed food twice a day and prefer to take the risk of causing another... (shrink)

The ArgumentThe purpose of this article is twofold. Firstly, I propose to analyze controversies using a “dialectical” model, in the sense described in Aristotle'sTopics. This approach presupposes that we temporarily disregard, for the sake of clarity, the concreteness of real life controversies in order to focus on their argumentative structure. From this point of view, the main advantage of controversies is that they allow the interlocutorsto testeach other's claims and therefore to arrive at relatively corroborated conclusions. This testing function in (...) a dialectical context is implemented through theassentto commonly accepted premises, and thenecessitywhich characterizes each step of the reasoning.Secondly, I shall apply this dialectical framework to the study of the controversy concerning the motion of the Earth, or rather a small episode of it. I shall examine an exchange of letters, written in 1616 and in 1624 respectively, between Galileo Galilei and Francesco Ingoli, one of his Aristotelian opponents. I shall then compare this exchange with the first day of Galileo'sDialogue Concerning the Two Chief Systems of the World, a fictional debate, where Galileo discusses some of the same arguments. While the first exemplifies what I call “negative” testing, and yields a refutation of the opponent's theses, the second exemplifies “positive” testing and yields a dialectical demonstration of the motion of the Earth. (shrink)

Over the past few years, there has been much debate about how autistic people should be described and labeled. Two main tendencies have emerged in this discussion, usually known as the person-first approach and the identity-first approach. While the former proposes to talk about ‘person(s) with autism’, the latter claims that ‘autistic person’ is more adequate. We first discuss person-first and identity-first approaches along with the reasons that have been offered for embracing one or the other. Then we focus on (...) the consequences that both approaches entail: first, the conception of autism as a condition, along with metaphysical conceptions of self and identity; second, linguistic emancipatory possibilities, such as reclamation. We argue that these two approaches ultimately promote a different stance on autism as a condition and that while the reclamation of ‘autistic’ is more clearly aligned with the identity-first view, the person-first approach is not entirely incompatible with some reclamation projects. (shrink)

In Category Mistakes, Magidor proposes that sortal restrictions should be viewed as pragmatic presuppositions. This contrasts with recent linguistic theories of successfully resolved category mistakes, e.g. coercions or copredication. It has been argued that for the proper treatment of such examples, sortal restrictions should be expressed by semantic presuppositions since they need to interact with compositional semantics. I explore possible ways in which Magidor’s theory could be extended to explain examples of coercion and copredication. The outcome of the discussion is (...) that incorporation of these facts into Magidor’s pragmatic system might be possible, but ecessitates choices that are far from trivial. (shrink)

Durante siglos lo que era un hecho que daba consistencia a la vida humana –cuidar– ha parecido ser sistemáticamente descatalogado y descargado de todo rango y categoría ética. La profusa presencia del cuidado en las fuentes griegas de la antigüedad desde la palabra epiméleia nos ha obligado a profundizar en los sentidos que la cura latina posee en la obra de Santo Tomás dada la preeminencia de esta para la teología moral posterior vinculada a la d– en el catálogo de (...) las virtudes junto con la misericordia, la beneficencia y la limosna que hacen operativa la caridad. El cuidar en su realización del amor irá más allá de socorrer las necesidades cuya forma verbal subvenio oscureció la cura y su sentido de atención, preocupación y ocupación activa por el prójimo.For centuries, what gave consistency to human life –to take care of- has seemed to be systematically discontinued and discharged of all rank and its ethical category. The abundant presence of care in the Greek sources of antiquity since the word epimeleia, has forced us to go deeper into the different meanings that the Latin word cura has in St Thomas’ work, given its prominence in a subsequent moral theology linked to charity. This requires a careful review of care as a virtue - to give it the majority of age- in the catalog of virtues together with mercy, beneficence and alms that make charity operational. Caring, in their realization of love, will go beyond needs help whose verbal form subvenio obscured its meaning of attention, concern and active occupation for the neighbor. (shrink)

Après avoir situé la démonologie de l’Aquinate par rapport à son angélologie et au dogme, l’article étudie les notions de bonté et intégrité de la nature des anges déchus, que Thomas d’Aquin élabore en s’appuyant sur le quatrième chapitre du De divinis nominibus. L’enquête est conduite à partir de l’examen du riche dossier angélologique constitué à l’occasion de la rédaction du De substantiis separatis et vise à préciser le rôle que la (re)lecture de Denys joue dans l’élaboration de la pensée (...) démonologique thomiste. On montre ainsi comment, en suivant Denys, Thomas harmonise la notion aristotélicienne de nature comme essence figée et inaltérable avec celle augustinienne d’une nature susceptible par contre d’amoindrissement et défaillance. Le but étant moins de caractériser la démonologie thomiste comme dionysienne que d’observer l’interaction substantielle chez Thomas entre sources et doctrine, on évoque le triptyque formé par l’opuscule inachevé De substantiis separatis et les commentaires au Liber de causis et à la Métaphysique comme dernier exemple de la manière de travailler de l’Aquinate, entre philosophie et théologie, tradition et spéculation. (shrink)

In the thesis some combinatorial statements are analysed from the reverse mathematics point of view. Reverse mathematics is a research program, which dates back to the Seventies, interested in finding the exact strength, measured in terms of set-existence axioms, of theorems from ordinary non set-theoretic mathematics. After a brief introduction to the subject, an on-line (incremental) algorithm to transitively reorient infinite pseudo-transitive oriented graphs is defined. This implies that a theorem of Ghouila-Houri is provable in RCA_0 and hence is computably (...) true. Interval graphs and interval orders are the common theme of the second part of the thesis. A chapter is devoted to analyse the relative strength of different characterisations of countable interval graphs and to study the interplay between countable interval graphs and countable interval orders. In this context the theme of unique orderability of interval graphs arises, which is studied in the following chapter. The last chapter about interval orders inspects the strength of some statements involving the dimension of countable interval orders. The third part is devoted to the analysis of two theorems proved by Rival and Sands in 1980. The first principle states that each infinite graph contains an infinite subgraph such that each vertex of the graph is adjacent either to none, or to one or to infinitely many vertices of the subgraph. This statement, restricted to countable graphs, is proved to be equivalent to ACA_0 and hence to be stronger than Ramsey's theorem for pairs, despite the similarity of partial order with finite width contains an infinite chain such that each point of the poset is comparable either to none or to infinitely many points of the chain. For each k less than or equal to 3, the latter principle restricted to countable poset of width k is proved to be equivalent to ADS. Some complementary results are presented in the thesis. (shrink)