The world seems ordered, going from past to present, linking cause and effect, because of our perspective. We superimpose order upon it, fixing events into a particular, linear series. We link events to outcomes, and this give us a sense of time.

But the universe is much more complex and chaotic than we can allow for, according to Rovelli. Humans rely on approximate descriptions that actually ignore most of the other events, relations, and possibilities. Our limitations create a false, or incomplete, sense of order that doesn’t tell the whole story.

The physicist argues that, in fact, we “blur” the world to focus on it, blind ourselves to see. For that reason, Rovelli writes, “Time is ignorance.”

Basically, he believes, time is a story we’re always telling ourselves in the present tense, individually and together. It’s a collective act of introspection and narrative, record-keeping and expectation, that’s based on our relationship to prior events and the sense that happenings are impending. It is this tale that gives us our sense of self as well, a feeling that many neuroscientists, mystics, and the physicist argue is a mass delusion.

Without a record—or memory—and expectations of continuation, we would not experience time’s passage or even know who we are, Rovelli contends. Time, then, is an emotional and psychological experience. “It’s loosely connected with external reality,” he says, “but it is mostly something that happens now in our head.”