Thomas Mormann (San Sebastian) gives a talk at the MCMP workshop "Influences on the Aufbau" (1-3 July, 2013) titled "(Re)constructing Influences in the Aufbau". Abstract: Once upon a time, the Aufbau was succinctly described as an attempt “to account for the external world as a logical construct of sense-data... .” Consequently, the most important influence on the Aufbau could be precisely named as “Russell”. These idyllic times have long passed. A comprehensive interpretation of the Aufbau has turned out to be a difficult task that has to take into account many, and sometimes rather turbid, sources. My thesis is that at the origin of the Aufbau project stood a problem that haunted German philosophy since the end of the 19th century at the latest. Bluntly, it may be expressed as the conflict between “Leben” and “Geist”. I want to show that there exists striking similarities between the attempts of how Rickerts System der Philosophie (1921) and Carnap’s (unpublished ms.) Vom Chaos zur Wirklichkeit (1922) (“the germ of the constitution theory”) aimed to cope with this problem.