The intellectual influences behind the nascent descriptive psychology that underlies the PES can be more properly understood by placing Brentano's thought in context. The historical context of Brentano's early thought and work will first be considered with a focus on his thought and activities before he undertook the project of the PES. This will require a brief account of Brentano's background with a special focus on his early development and the intellectual context of his thought. After a brief presentation of the necessary biographical information, the current chapter outlines and summarizes how ideas stemming from Brentano's early schooling and initial teaching period at Würzburg contributed to the theories that later emerged as the theoretical framework for the PES.¹