Perhaps our greatest difficulty in dealing with tinnitus is that our understanding of how sound energy is transformed into neural impulses is still rather theoretical. The transduction process of the hair-cell receptor is still not entirely understood. Nevertheless, Davis’ (1961, 1965) principles of sensory action and his model of the hair-cell transduction process (1965) have provided a useful framework for our thinking and have helped to guide investigations into the sensory physiology of hearing. I would like to review some of these principles in a vein similar to that of Tonndorf (1975). In so doing, I can reveal the strengths and weaknesses of our knowledge of how the ‘ear’ works.

Figure 1 illustrates some of the sailient features of sensory systems in general. Several electrical events are elicited upon stimulation: a receptor potential, a generator potential, and spike-action potentials. The relation of the receptor and generator potentials to the stimulus waveform and to one another depends upon the specific method of coupling the stimulus energy to the receptor, and the characteristics of the connection between the receptor and the sensory neuron.