The theory that receptors and neural channels for different senses use different, independent nerve energies. This doctrine was proposed by Johannes Muller in the early 1800s, before knowledge of action potentials in an attempt to explain how we could tell the difference between senses. Example: any stimulus that affects the eye will be interpreted as visual. This is incorrect; there are no different “nerve energies”. They’re all action potentials. The brain recognizes different sensory signals because these signals come from different sensory nerve tracts (labeled lines).