Abstract: This paper investigates modals in Linguistics and Engineering research articles. The study has two main objectives. The first one concerns the identification and categorization of modals used in research articles written in English by native speakers. The second objective is of a contrastive nature. We are much interested in measuring the use and function of modals according to register. For this study, we focus on material traditionally categorized as belonging to the realm of the humanities, e.g. linguistic research, and material categorized as belonging to the hard sciences, e.g. engineering research. Without further considerations as to the suitability of these categories, we want to explore on the motivations behind the use of modals in these branches of scientific thought. Our corpus was gathered for this purpose in mind with a selection of papers from the humanities and the hard sciences. Although corpus tools are fundamental for statistical representations, manual analyses are also important in order to detect pragmatic use of language denoting authority or lack of it. Our conclusions report on the motivations leading to the use of modals in relation to register.