La nature a des effets positifs sur la santé (Moore, 1981 ; Ulrich, 1984). Les premiers travaux se sont inspirés de la médecine ancestrale japonaise avec la prescription aux patients de bain de forêt, afin de renforcer leurs défenses immunitaires et leur bien-être (Li, 2010). Par la suite les recherches ont montré qu’une simple exposition visuelle à la nature pouvait produire les même effets (Beukeboom, Langeveld, & Tanja-Dijkstra, 2012). À l’heure actuelle les travaux se basent sur deux grands courants pour expliquer les effets de la nature sur la santé, à savoir la biophilie (Ulrich, 1993 ; Wilson, 1984) et la théorie de la restauration de l’attention (R. Kaplan & Kaplan, 1989 ; S. Kaplan, 1995). Cependant aucun de ces travaux n’a été mené en France. La littérature a montré que certains effets étaient sensibles à la culture du pays (Pascual et al., 2012). Les travaux ont été menés en utilisant uniquement de la nature verte sous temps clément. Huit expérimentations ont été conduites, manipulant différents types d’expositions à la nature, avec différentes scènes de nature. Les résultats montrent que les effets de la nature sont présents en France, sans différenciation du type de nature. Que celle-ci soit verte ou non, par beau temps ou non, en présence d’éléments aquatiques ou sans, nous observons des effets positifs de la nature. Nous montrons également qu’une stimulation olfactive de la nature produit des effets semblables aux stimulations visuelles. Les résultats que nous obtenons semblent être fortement liés à la notion de contrôle perçu (liberté). / Nature has indisputable effects on human health (Moore, 1981; Ulrich, 1984). The very first research works on this topic were inspired by traditional Japanese medicine. Indeed, at that time, “forest baths” were typically prescribed to patients, in order both to strengthen their immune system and to improve their well-being (Li, 2010). Interestingly, subsequent researches have demonstrated that solely a visual exposure to Nature was able to produce the same effects (Beukeboom, Langeveld, & Tanja-Dijkstra, 2012). To explain this impact of Nature on human health, both biophilia (Ulrich, 1993; Wilson, 1984) and the attention restoration theory (R. Kaplan & Kaplan, 1989; S. Kaplan, 1995) are the two main trends nowadays used by the scientific community. Nevertheless, none of these experiments were carried out in France, while it is clearly established that country’s culture has a significant influence on this Nature effect (Pascual et al., 2012). Moreover, it is relevant to note that up to now all the researches were only performed under both green Nature exposure and mild weather conditions. With the aim of starting to decipher more precisely the influence of the presence of a Nature component on human health and prosocial behavior, this present thesis describes eight experiments carried out in France, with several kinds of Nature exposures and Nature scenes. Results highlight the positive effects of Nature, whatever its type, i.e. green or not, in mild weather or not, with or without aquatic component, etc. Furthermore, this work brings to light than an olfactory stimulation (i.e. using fragrances of Nature) generates similar effects compared to a visual one. Altogether, the results appear to be closely related to the perceived control (freedom).

The aim of this study is to examine the meaning and the morality of suicide through the history of philosophy. To this aim, firstly, the historical evaluation of the concept of suicide is explained in detail. The effects of sociological and the religious transformations on the meaning of suicide are analyzed. Afterwards, the moral theories about suicide are discussed. The anti-suicide arguments about suicide in the history of philosophy are classified under three parts mainly. These anti-suicide arguments &mdash / that suicide is a violation of our duties to God, to the society and to the self &mdash / are handled and explained in detail with their counter arguments. Then, the problem of the permissibility of suicide is analyzed and whether suicide is morally permitted under some conditions or it is absolutely forbidden is discussed. Next, the philosophical meaning of suicide in literature is investigated by analyzing the meanings that are given to suicide by Dante iv and Dostoevsky. In the conclusion, a brief summary is given, and the moral theories about suicide are criticized. ,