The part of thinking that’s easy to handle is the part that works by analogy with speech. Thinking in words, speaking our thoughts internally, projects an auditorium inside our skulls. Dark or bright, a shadow theater or a stage scorched by klieg lights, here we try out voices, including the voice we have settled on as the familiar sound of our identity, although it may not be what other people hear when we speak aloud. But that is the topmost of the linguistic processes going on in the mind. Beneath the auditorium runs a continuous river of thought that not only is soundless but is not ordered so it can be spoken. For obvious reasons, describing it is difficult. If I dip experimentally into the wordless flow, and then try to recall the sensations of it, I have the impression of a state in which grammar is present – for when I think like this I am certainly construing lucid relationships between different kinds of meaning, and making sense of the world by distinguishing between (for a start) objects and actions – but thought there are so to speak nounlike and verblike concentrations in the flow, I do not solidify them, I do not break them off into word-sized units. Are there pictures? Yes, but I am not watching a slide show, the images do not come in units either. Sometimes there’s a visual turbulence – rapid, tumbling, propelled – that doesn’t resolve into anything like the outlines of separate images. Sometimes one image, like a key, will hold steady while a whole train of wordless thoughts flows from its start to its finish. A mountain. A closed box. A rusty hinge.