What did Francis Bacon mean in his 1620 Novum Organum when he proclaimed that he had “supplied the Instrument (Equidem Organum probui)” to solidly found philosophy and the sciences on every kind of experience? What did René Descartes mean when he wrote to Mersenne that his Discours de la méthode consisted “more in practice than theory” and to princess Elisabeth that in order to always be prepared (disposé) to judge well, one needed two things: the knowledge of truth and the habit (l’habitude) of remembering and recognizing this knowledge every time one stood in front of it. Why did David Hume’s philosophy of knowledge relied so heavily upon habit, or custom? So much so that without customary conjunction there simply was no knowledge of the world? These abstract early modern “instruments” were as much dependent on practical habits (or practical schemes) as were material instruments—such as the telescope, the air pump and a plethora of mathematical instruments. In this paper I want to explore (I should perhaps say follow) the trajectories of these diverse objects: what define them as instruments (organum), how distinctive practical habits (habitus) were for each instrument, and finally how should we reconcile these early modern instruments and practices with our vastly different intellectual and cultural contemporary context (museum). There exist a widening gap between the production of scholarly works on scientific instruments and their showcasing in brightly lit and decontextualized museum spaces. The questions are twofold: why care? And how to bridge this gap? Mapping the trajectories between early modern instruments and today’s museums may actually compel us to look back at these objects and reevaluate our understanding of their inner practical and operational attributes.