Final answer:
Hermann von Helmholtz's work on the speed of nerve conduction provided evidence of the mind having a physical basis.
Step-by-step explanation:
Hermann von Helmholtz's work on the speed of nerve conduction provided further evidence that the mind had a physical basis. Helmholtz conducted experiments to measure the speed at which nerve impulses travel through the body. His research showed that the mind is connected to the body through the nervous system and that mental processes are dependent on physical processes in the body.