So I’m reading physicist Brian Greene’s new book, “Till the End of Time”, and in it he references Michael Graziano’s schema-based theory of consciousness, under a nicely succinct subheading “The Mind Modeling The Mind”. The theory is, basically, when a conscious mind is contemplating an object (in Greene’s example, a Ferrari), it creates a simplified model of that object and its attributes, but furthermore, it creates a model of a conscious mind paying attention to that object. This model of the mind is what give us the feeling of being conscious.

That made me think (and I’m trying to remember if it was discussed in Graziano’s book) that the defining characteristic of being conscious is the temporal concept of “now”. That is to say, a subjective (to me, myself, and I) moment in time that moves through a narrative, a story of what’s happening right now to that model of myself paying attention to something. It’s this concept of “now” that can then process any “then” (not now) – in other words, the past and the future. The now, the conscious present, can dive into the data of the recorded past (in my brain) to project a simulation of the future.

Sounds exhausting. That’s probably why we need to sleep, or lose consciousness, periodically, during which we lose all concept of now (unless we are consciously dreaming). Our brains clearly need rest from this exhausting effort of modeling our current moment in time, all the time.