Héloïse Athéa

Model organisms play a central role in biological research, yet the conceptual questions they raise continue to provoke debate among philosophers. This article examines one such question: What are the distinctive features that qualify model organisms as scientific models? Building on and extending previous work, we propose a refined conceptual framework for understanding model organisms in the context of contemporary scientific practice. Our framework highlights six key features that, collectively, uniquely characterize model organisms. We argue that model organisms should not be viewed merely as components within experimental systems but rather as autonomous experimental systems in their own right.

Model organisms (MOs) are indispensable in modern biological and biomedical research, yet frameworks for their evaluation remain underdeveloped. In particular, no consensus exists on how, and to what extent, findings from one species can be generalized to others, including humans. We address this gap by introducing a comprehensive, multi-criteria framework that integrates both internal and external validity. We propose to assess internal validity by examining the reliability of experimental measurements and the inferences that translate those data into biological phenomena. External validity, or generalizability, is guided by four distinct types of similarity — material, functional, manipulation-induced, and phenomenological — each situated at explicit biological levels (molecular, cellular, physiological, etc.) and qualified by their evidential strength. We unite these elements under the metaphor of a “validity ladder”: each well-supported similarity adds a rung linking the model to its target, and the ladder remains dynamic — new data may reinforce existing rungs, add stronger ones, or reveal weak links. The overall robustness of the scale also depends on how rungs, or similarities, across biological levels interconnect (what we call “cross-links”). Importantly, the specific research objective guides the evaluation process, assigning greater or lesser weight to each rung. By formalizing this procedure, our framework not only enriches the philosophical understanding of MOs as representational and interventional tools but also provides researchers with operational criteria for designing, interpreting, and refining model-based studies.

In contemporary biology laboratories, animal models have become essential scientific tools. From modeling psychiatric disorders to investigating embryonic development and genetic diseases, they facilitate research across various fields. Although scientists are generally cautious about extrapolating results from these models, this paper introduces a thought-provoking case study–the three-criteria addiction model–which boldly endeavors to induce “full addiction” in laboratory rats. Given the model’s influence in the field of behavioral neuroscience, this paper aims to conduct its comprehensive epistemic analysis, exploring whether “addicted rats” genuinely exist and the potential implications for understanding addiction and mental disorders. Conducting such an epistemic analysis presents a difficulty in itself due to the heterogeneity of approaches employed by philosophers of science to analyze animal models. The second objective of this paper is, therefore, to propose a general method to guide epistemic scrutiny of animal models.

Théodule Ribot est l’un des premiers à penser les rapports entre mémoire et émotions. Au sein de ce qu’il appelle la « mémoire affective », il décèle une mémoire spécifique des émotions. Il s’ensuit un débat sur l’existence, la définition et le contenu de cette mémoire. Après les propositions initiales de Ribot, on observe l’émergence progressive d’un consensus : même s’il est possible de distinguer la mémoire affective de la mémoire intellectuelle, tout souvenir présente à des degrés variables des éléments intellectuels et des éléments affectifs. Si, dans le cadre académique, ces débats sont tombés dans l’oubli, on peut établir une continuité conceptuelle avec la recherche scientifique actuelle, qui gagnerait à relire cette littérature centenaire.

Understanding the relations between mind, brain and behavior is an enduring challenge for science and philosophy. The present article focuses on the concept of internal states, of which emotions are the most studied subtype, in the recent neuroscientific literature. Internal states are conceived by neuroscientists as functional states implemented in neural circuits that drive behavior. To begin, we discuss current definitions of internal states, that emphasize both their intrinsic and relational properties. We stress the difference between preliminary characterizations of these states (that allow researchers to track them) and findings related to their intrinsic nature. We analyze three experimental studies interpreted within this framework, and outline the role of innovative methods in the process of discovery. We interpret the families of states under investigation as homeostatic property clusters, and suggest that the work of Anderson and Adolphs offers a solution to the problem of what constitutes a natural kind in neuroscience. Concerning the relationship between physical states of the brain and mental states, we make explicit the discrepancy between an eliminativist and a reductive project within the literature, and underline the importance of a choice between them. Finally, we suggest that studies of internal states have three interrelated objectives: a better grasp of brain-behavior relationships, a more principled attribution of mental states to nonhuman animals, and better animal models of our own internal states in clinical contexts. With this plurality of objectives comes a plurality of possible outcomes of ongoing research.

De la drosophile à la souris, en passant par le poisson-zèbre, les organismes modèles façonnent le paysage de la biologie contemporaine. Au sein des pratiques de modélisation en sciences, ces modèles sont non seulement très particuliers, mais font aussi l’objet d’utilisations très variées. Dans ce contexte, cet article vise deux objectifs : d’une part, proposer une description suffisamment générale pour englober tous les usages qui en sont faits, tout en essayant de caractériser la spécificité de ces modèles. D’autre part, il s’agit de dégager les rôles épistémiques généraux que l’on peut attribuer à ces modèles. Au-delà de leur fonction représentationnelle, nous en proposons deux : celui d’instruments de mesure, et celui de supports pour la découverte d’explications de phénomènes biologiques.