This thesis investigates whether beliefs acquired by way of prophecy are safe. By ‘prophecy’ I have in mind the presentation of the prophetic method as found in the Guide of the Perplexed, which was Moses Maimonides’ philosophical masterpiece. And by ‘safe’ I have in mind the work by Timothy Williamson on the safety condition for knowledge. Both authors have proven to be dominant forces on these respective topics. The significance of this investigation derives from the centrality of prophecy to the three monotheistic religions. My main goal in this thesis is to identify those safety risks associated with the prophetic method. In this manner I aim to undermine any presumption in favor of prophetic beliefs as a whole being safe. Importantly, this general conclusion does not entail of a specific prophetic belief p that p is unsafe. Additionally, the scope of these results is restricted to the model of prophecy found in the Guide. The thesis begins with a critical elucidation of Williamson’s extensive work on the safety condition for knowledge. Particular attention is paid to those issues related to method individuation and Williamson’s cumulative conception of bases. Matters concerning these two topics inform the reading of Maimonides on prophecy found in the second chapter. In particular, I argue that Maimonides should be read as defending a cumulative conception of prophecy. As I emphasize several times during the chapter, the epistemology of prophecy cannot be reduced to the epistemology of testimony since prophecy for Maimonides does not involve the transfer of a proposition from God to the prophet. The third chapter is devoted to identifying those elements of the prophetic method that involve room for error. I argue that while all belief-forming methods in a fallibilist epistemology contain room for error, some are riskier than others. Prophecy should be considered one of the riskier sort. The fourth and final chapter shifts attention to non-standard semantics for ‘knows,’ David Lewis’s in particular. I argue that the interaction between such semantics and the laws governing prophecy in Jewish law is problematic. In particular, I demonstrate that such semantics destabilize the prophetic phenomenon. As such, we must either choose invariantism and gain stability, or choose non-standard semantics for ‘knows’ and live with this lack of stability.

Lévolution des modes de vie conduit à une évolution des besoins et des souhaits des personnes, en quête «d'expérience », de « bien-être » et de « plaisir » à travers les produits qu'elles utilisent. Les entreprises doiventaujourd'hui satisfaire et séduire ces personnes de plus en plus exigeantes, en étant source d'innovation et denouveauté. Ainsi, elles s'intéressent de plus en plus dans leur démarche de conception de produits à une meilleureprise en compte du facteur humain. Faire vivre aux personnes des expériences positives et de qualité, demandeune démarche spécifique qui les placent au centre des préoccupations des acteurs-métier de la conception deproduits. Dans ce contexte, le processus de conception requiert l'intervention de différentes disciplines sensiblesjustement au facteur humain. Ainsi dans le cadre de nos travaux de recherche, nous nous sommes intéressés aurapprochement de l'ergonomie et du design, deux disciplines sensibles aux personnes qui évoluent vers denouvelles pratiques : le design pour « des besoins » et l'ergonomie prospective. Nous axons nos travaux derecherche sur les pratiques de ces deux disciplines qui convergent vers une vision commune, prospective et «humaniste » de la conception de produits, pour une meilleure prise en compte des personnes. Le principal enjeuscientifique de notre travail est de mieux cerner les pratiques actuelles, de l'ergonomie et du design dans uncontexte de conception de produits. Ceci, pour proposer à ces acteurs-métier une démarche (IDLifeS) et des outils(Guides de Connaissances), interdisciplinaires, qui correspondent à l'évolution de leurs pratiques respectives et quileur permettent de co-concevoir des produits et des situations de vie qui correspondent aux besoins, aux souhaits etaux caractéristiques des personnes. / Lifestyles change led to the development of the needs and wishes of people who are looking for "experience", "wellbeing"and "pleasure" through the products they use. Companies must now satisfy and seduce these people whoare increasingly exigent, by being a source of innovation and new ideas. Thus, companies are more and moreinterested in their product design process, in order to better take into account, the human factor. It requires aspecific approach to make people have positive and quality experiences. In this approach, people are at the heart ofthe concerns of the product design actors. In this context, the design process requires the intervention of differentdisciplines rightly sensitive to human factor. In our research, we focused on ergonomics and design, two disciplinessensitive to people who are moving towards new practices: design for "needs" and the prospective ergonomics. Ourresearch is focus on the practices of these two disciplines that converge on a common vision, which is a prospectiveand "humanist" one, of the product design for a better integration of people. The main scientific challenge of ourwork is to better understand ergonomics and design current practices in a product design context. This, to suggestto these actors an approach (IDLifeS) and tools (Knowledge Guides), interdisciplinary, which correspond to thedevelopment of their practices and offer them to co-design products and life situations which correspond to theneeds, wishes and characteristics of people.