 Descriptive psychology’s second task is the classification of acts or psychical functions. This classification is based on the distinction between two classes of acts: intellectual and emotional functions. All functions that fall under either of these two classes have relationships ranging from the simplest to the most complex, so that functions of the second class presuppose, and are based on, lower level functions of the first class. This class of intellectual functions subsumes all acts ranging from sense perception to judgment. Sense perception in this classification has a particular status because it gives direct access to first-order phenomena and as such it is the function of consciousness (attention) through which something is noticed or apprehended. It serves as the foundation of all functions in that it provides them with their sensory material. Between perception and judgment, there is a series of intermediate acts: the act of presentation, which has as content second order phenomena, the act of abstraction and what Stumpf calls the acts of synthesis, whose specific contents are sets (Inbegriffe).