Gustav Fechner
Fechner, along with Wilhelm Wundt and Hermann von Helmholtz, is recognized as one of the founders of modern experimental psychology. His clearest contribution was the demonstration that because the mind was susceptible to measurement and mathematical treatment, psychology had the potential to become a quantified science. Theorists such as Immanuel Kant had long stated that this was impossible, and that therefore, a science of psychology was also impossible.
Psychology
Credit for the first psychology clinic in the United States typically goes to Lightner Witmer, who established his practice in Philadelphia in 1896. Another modern psychotherapist was Morton Prince. For the most part, in the first part of the twentieth century, most mental health care in the United States was performed by specialized medical doctors called psychiatrists. Psychology entered the field with its refinements of mental testing, which promised to improve diagnosis of mental problems. For their part, some psychiatrists became interested in using psychoanalysis and other forms of psychodynamic psychotherapy to understand and treat the mentally ill. In this type of treatment, a specially trained therapist develops a close relationship with the patient, who discusses wishes, dreams, social relationships, and other aspects of mental life. The therapist seeks to uncover repressed material and to understand why the patient creates defenses against certain thoughts and feelings. An important aspect of the therapeutic relationship is transference, in which deep unconscious feelings in a patient reorient themselves and become manifest in relation to the therapist.