The author hypothesizes that in the era of information technology, logic is the crucial tool of security sciences, and logicians have a greater role to play in this field than politicians. This viewpoint is held by two significant institutions dealing with the logic of security: Academia Diplomatica Europaea (ADE) in Brussels and US Army War College in Carlisle, Pennsylvania. The author focuses on the assumptions and activities of Academia Diplomatica Europaea. ADE assumes that the major challenge to contemporary security is to change the enemy’s mentality into the mentality of an ally. To do this, one should analyse the following logical categories: the category of relations (between individuals and societies) and the category of hostility. ADE mainly focuses on social relations, with their sociological and psychological aspects, assuming that enemies have not only official, explicit opinions but also implicit ones, and learning these implicit opinions is a key to change the enemy’s mentality according to the aforementioned pattern. The author then discusses the methods relating to the logic of security used by ADE. Finally, in the light of the assumptions stated by ADE, he analyses the institution’s activities aimed at contemporary threats, the major threat being, according to ADE, terrorism.