<P> The law of specific nerve energies, first proposed by Johannes Peter Müller in 1835, is that the nature of perception is defined by the pathway over which the sensory information is carried . Hence, the origin of the sensation is not important . Therefore, the difference in perception of seeing, hearing, and touch are not caused by differences in the stimuli themselves but by the different nervous structures that these stimuli excite . For example, pressing on the eye elicits sensations of flashes of light because the neurons in the retina send a signal to the occipital lobe . Despite the sensory input's being mechanical, the experience is visual . </P> <P> Here is Müller's statement of the law, from Handbuch der Physiologie des Menschen für Vorlesungen, 2nd Ed., translated by Edwin Clarke and Charles Donald O'Malley: </P> <Dl> <Dd> <Dl> <Dd> The same cause, such as electricity, can simultaneously affect all sensory organs, since they are all sensitive to it; and yet, every sensory nerve reacts to it differently; one nerve perceives it as light, another hears its sound, another one smells it; another tastes the electricity, and another one feels it as pain and shock . One nerve perceives a luminous picture through mechanical irritation, another one hears it as buzzing, another one senses it as pain...He who feels compelled to consider the consequences of these facts cannot but realize that the specific sensibility of nerves for certain impressions is not enough, since all nerves are sensitive to the same cause but react to the same cause in different ways...(S) ensation is not the conduction of a quality or state of external bodies to consciousness, but the conduction of a quality or state of our nerves to consciousness, excited by an external cause . </Dd> </Dl> </Dd> </Dl>

According to the doctrine of specific nerve energies