section_path: Etymology and definitions
section_name: Etymology and definitions
paragraph_text: Etymology and definitions
  
  The word psychology derives from the Greek word psyche, for spirit or soul. The latter part of the word psychology derives from -λογία -logia, which means "study" or "research". The word psychology was first used in the Renaissance. In its Latin form psychiologia, it was first employed by the Croatian humanist and Latinist Marko Marulić in his book Psichiologia de ratione animae humanae (Psychology, on the Nature of the Human Soul) in the decade 1510-1520 The earliest known reference to the word psychology in English was by Steven Blankaart in 1694 in The Physical Dictionary. The dictionary refers to " Anatomy, which treats the Body, and Psychology, which treats of the Soul."
  
  Ψ (psi), the first letter of the Greek word psyche from which the term psychology is derived, is commonly associated with the field of psychology.
  
  In 1890, William James defined psychology as "the science of mental life, both of its phenomena and their conditions." This definition enjoyed widespread currency for decades. However, this meaning was contested, notably by radical behaviorists such as John B. Watson, who in 1913 asserted that the discipline is a natural science, the theoretical goal of which "is the prediction and control of behavior." Since James defined "psychology", the term more strongly implicates scientific experimentation. Folk psychology is the understanding of the mental states and behaviors of people held by ordinary people, as contrasted with psychology professionals' understanding.