The distinction we make between five different senses is a universal one. Rather than speaking of generically perceiving something, we talk of perceiving in one of five determinate ways: we see, hear, touch, smell, and taste things. In distinguishing determinate ways of perceiving things what are we distinguishing between? What, in other words, is a sense modality? An answer to this question must tell us what constitutes a sense modality and so needs to do more than simply describe differences in virtue of which we can distinguish the perceptions of different senses. There are many such differences – the different perceptions involve different sense organs, sensitivity to different kinds of stimuli, the perception of different properties, and they involve different kinds of experiences – but which, if any, of these differences are the differences that really matter?