Law of specific nerve energies

The law of specific nerve energies, proposed by the physiologist Johannes Peter Muller in 1835, is a principle of sensory physiology holding that the character of a perception is determined by which nerve pathway carries the signal to the brain rather than by the nature of whatever stimulus set it off. Under this law, visual, auditory and tactile experiences differ from each other not because of any inherent difference in the stimuli themselves but because they travel along distinct neural pathways; the classic illustration is that pressing on the eye produces a sensation of light because the stimulated retinal neurons still send their signal to the occipital lobe, so a purely mechanical stimulus is experienced as vision even though no light is actually involved.