During the Renaissance, the five senses were understood to form a hierarchical system from the highest sense of vision down to touch. Vision was correlated to fire and light, hearing to air, smell to vapour, taste to water, and touch to earth.
Perhaps the human fascination with fire stems from the totality of its sensory stimulation. The fire gives a flickering and glowing light, ever moving, ever changing. It crackles and hisses and fills the room with the smells of smoke and wood and perhaps even food. It penetrates us with its warmth. Every sense is stimulated and all of their associated modes of perception, such as memory and an awareness of time, are also brought into play, focused on the one experience of the fire. Together they create such an intense feeling of reality, of the "here and nowness" of the moment, that the fire becomes completely captivating.
As George Lakoff and Mark Johnson made clear in their touchstone book Metaphors We Live By, metaphors are the basis of all human thought and reasoning. The metaphors we use to speak about the web are not simply linguistic trivia – they determine how we understand it on a fundamental level. It determines what we think the web is capable of, what risks, opportunities, and challenges it poses. Which means the metaphors we use to think about the web profoundly influence what we think the web is, what we think we can do with it, and how we might change or evolve it.
…Out of all of these metaphors [for the web], the two most enduring are paper and physical space.