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.
Ernst Heinrich Weber
Weber is often cited as the pioneer or father of experimental psychology. He was the first to conduct true psychological experiments that held validity. While most psychologists of the time conducted work from behind a desk, Weber was actively conducting experiments, manipulating only one variable at a time in order to gain more accurate results. This paved the way for the field of psychology as an experimental science and opened the way for the development of even more accurate and intense research methods. 
One of Weber’s greatest influences was on Gustav Fechner. Weber was appointed the Dozent of Psychology at the University of Leipzig the same year that Fechner enrolled. Weber’s work with sensation inspired Fechner to further the work and go on to develop Weber’s law. At the time of his sensation work, Weber did not fully realize the implications that his experiments would have on understanding of sensory stimulus and response.