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.
Edwin Boring
Edwin Garrigues (Gary) Boring (23 October 1886 – 1 July 1968) was an American experimental psychologist, Professor of Psychology at Clark University and at Harvard University, who later became one of the first historians of psychology. A "Review of General Psychology" survey, published in 2002, ranked Boring as the 93rd most cited psychologist of the 20th century, tied with John Dewey, Amos Tversky, and Wilhelm Wundt.