Seeing is the property of our eyes. But we also use this word in other senses, when we apply the power of vision to knowledge generally. We do not say 'Hear how that flashes', or 'Smell how bright that is', or 'Taste how that shines' or 'Touch how that gleams'. Of all these things we say 'see'. But we say not only 'See how that light shines', which only the eyes can perceive, but also 'See how that sounds, see what smells, see what tastes, see how hard that is'. So the general experience of the senses is the lust, as scripture says, of the eyes, because seeing is a function in which eyes hold the first place but other senses claim the word for themselves by analogy when they are exploring any department of knowledge.