In an average 24-hour period, how much time do you spend asleep? The answer is likely to be around 8 hours, but let’s look more closely. What do you mean by “asleep”? This might sound like an obvious question, to which you’ll probably answer, “Eyes closed, not aware of anything, deep and regular breathing.” And what do you mean by “awake”? This also seems obvious, and the answer would probably be along the lines of, “Open my eyes, get up and dress for work, and stay that way until I go to sleep again that night.” What this suggests is that there are two states of consciousness, awake and asleep.

We’re not going to digress into philosophical arguments about what consciousness is, but our everyday model of a simple dichotomy between ...

Get Work without Stress: Building a Resilient Mindset for Lasting Success now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.