What is Psychology? psychology is the scientific study of mind and behavior why is psychology scientific? because it is based on empiricism the notion that all knowledge can be acquired through observation, not on reasoning, tradition or common sense psychology is the scientific study of mind and behavior mind the contents of subjective experience sensations, thoughts, emotions behavior observable actions though and feelings activities of cells Roots of Modern Psychology in the late 1800s, both physiologists and philosophers were investigating the mind philosophy - "why" physiology - "how" philosophy - ideas about the acquisition of knowledge physiology - progress in understanding the nervous system, senses, etc. both came together to create the idea of applying the methods of science to the study of humans