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.
James Mark Baldwin
James Mark Baldwin (January 12, 1861, Columbia, South Carolina – November 8, 1934, Paris) was an American philosopher and psychologist who was educated at Princeton under the supervision of Scottish philosopher James McCosh and who was one of the founders of the Department of Psychology at the university. He made important contributions to early psychology, psychiatry, and to the theory of evolution.