Brentano is perhaps most famously renowned for his re-deployment of Scholastic terminology of ‘intentional act’ and ‘intentional object’ in the elaboration of his novel science of ‘descriptive psychology’ in the mid-1870s and 1880s. In this re-deployment, however, Brentano adapted the original Scholastic meanings of both of these terms. Thus Brentano advanced not one but two descriptive-psychological theses of intentionality.1 These theses, however, are often not properly distinguished, and consequently they are more often confused. Nevertheless, once the two theses are distinguished, Brentano’s basic descriptive-psychological tenet of the intentionality of consciousness is more readily understandable on its own terms. Whether Brentano’s descriptive-psychological tenet is entirely acceptable philosophically, or not, of course, is another matter but this presupposes understanding in a straightforward sense what Brentano’s doctrine is. In this article, I will be concerned mainly with Brentano’s re-introduction of ‘what the Scholastics of the Middle Ages called the intentional (or mental) inexistence of an object’ in Psychology from an Empirical Standpoint (1874),2 even though it is Brentano’s (second) thesis on ‘intentional act’, one that he developed after his 1874 publication, that is more generally well known and examined. While acknowledging that many versions of ‘Brentano’s thesis’, as it is usually (and loosely) referred to by commentators today, have been re-worked in modern philosophy of mind, this article focuses attention on some of the main points of convergence and deviance between the original Scholastic concept and Brentano’s ‘new’ concept of intentionality in Psychology from an Empirical Standpoint.