“For the fact is that neuroscientists who study memory remain unclear on the question of whether each time we remember something we are accessing a stable “memory fragment”—often called a “trace” or an “engram”—or whether each time we remember something we are literally creating a new “trace” to house the thought. And since no one has yet been able to discern the material of these traces, nor to locate them in the brain, how one thinks of them remains mostly a matter of metaphor: they could be “scribbles,” “holograms,” or “imprints”; they could live in “spirals,” “rooms,” or “storage units.” Personally, when I imagine my mind in the act of remembering, I see Mickey Mouse in Fantasia, roving about in a milky, navy-blue galaxy shot through with twinkling cartoon stars.”