Psychology is usually defined as the scientific study of the human brain and behavior. But the etiology of the word psychology reveals, at a worldview level, that definition is incomplete.
Psychology is the study of psych, or more accurately, the psyche (pronounced sy-key).
The root of the word psyche is the Greek word psuche (Strongs #5590). Psuche had two meanings. It meant the “life force”; that which animates all life on earth. Psuche differentiates life from non-life. All life, at least all animal life, had psuche. Psuche is as common as life. In this sense, psychology is the study of that which is common.
But psuche had a second meaning. Psuche also described something uniquely human, something special, and something spiritual. In this sense, psychology is the study of that which is spiritual and special and uniquely human.
Psychology is the study of the brain and behavior, but from a Christian perspective, it is also the study of that which is uniquely human and spiritual. A fuller definition understanding of psyche includes our heart, soul, and mind. As such, psychology is interested in topics dear to a Christian worldview – topics dealt with extensively in the Bible.