Psychology is very young branch of science (Freud lived less than 200 years ago) and its subject matter is vast and complex: from low level neural mechanisms to

Psychology is very young branch of science (Freud lived less than 200 years ago) and its subject matter is vast and complex: from low level neural mechanisms to perception to higher cognitive functions to mental illnesses to human cognitive development to behavioral psychology to decision making. Take, for example, schitzophrenia and bipolar disorder. Even if we don't understand them at the lower level and don't properly understand their treatments, we have become much better at diagnosing them early enough to help people from ruining their lives. It's a huge step forward. Or at the lower levels, consider human perception systems. We start to understand how early layers of vision work, even if we don't yet have a good grasp of how higher levels of visual cognitive system work.