The Italian physicist Carlo Rovelli tells us in his international bestseller, Seven Brief Lessons on Physics, that “there is a detectable difference between the past and the future only when there is the flow of heat.” The flow of time, he writes, is a matter of thermodynamics, subject to the vagaries of probability. Building on Einstein’s amply verified theory of relativity, Rovelli says that just as there is no definitive “here” in relation to other points of reference, neither is there an objective “present” in terms of time. Our sense of passing time, he explains, arises from “microscopic interactions within the world” that are part of “systems” such as human consciousness and memory. That about wraps it up, I guess, if you’re a physicist.

Time remains a mystery, Rovelli admits, but he does a formidable job reducing it to a blur of subatomic particles perceived within the limitations of human consciousness, including the finest of scientific calculations. Given the limitations of my non-physicist consciousness, I think he’s on to something beyond physics when he identifies heat as the sole detectable factor separating our past from our future.

Put in more human terms, is heat rather akin to attention? If we put our attention on someone, are we not transmitting an immeasurable but sometimes detectable impulse of energy towards them—such as when we sense someone looking at us? Keeping things strictly materialistic, our brains consume energy, so can we not consider mental impulses that require the brain’s energy as some version of heat? Looking at it another way, isn’t attention what enables us to distinguish what has happened from what is happening?

What, though, about things that have taken place in the past but linger in our minds so that they remain alive in the present, events and people we still care about, puzzle over, continue to study, imitate? Lingering objects of attention give force to Faulkner’s famous line, perhaps alluding to the South’s role in the Civil War, “The past is never dead. It’s not even past.” The parts of the past that do not die are those that draw enough of our attention for them to stick in our memory. The elasticity of human reactions allows for widely differing perspectives on past events. The pioneers’ brave expansion and settlement of the American West looks very different from the standpoint of Native Americans, whose tribal lands were overtaken, treaties broken, burial grounds desecrated, and so on.

We give certain experiences more attention than others because they elicit some form of psychological heat – curiosity, fear, admiration, humor, regret, love, resentment, hope, etc. From what I’ve read about how the human brain works, items that stay in our memory are glued to or associated with emotions of some kind. Otherwise they are not retained, at least in that person’s memory.

Think of what an enormous effusion of, shall we say, attention quanta, human beings (not to mention other beings) emit daily. From the homeliest impulse to get up in the morning, to numberless types of effort put forth by multitudes throughout their day’s labor—to serve others, to deal with all manner and size of interpersonal conflicts, to keep informed about what’s happening around us. Within this huge output of attention impulses are, say, quarks of different types of attention—from the keenest concentration required for original work of any kind, to the tedious forms of labor done solely for a paycheck, to routine tasks of personal hygiene, transportation, shopping, housekeeping and so on.

Good luck trying to fathom the myriad attention units devoted to sexual desire, romantic love, and the equally vital efforts of friendship.

Attention quanta may also differ in terms of age and stages of consciousness. The very young survive by focusing on those who take care for them, because their lives depend on whether they receive nurturing attention. Children soon face the demands of schooling, and meet various degrees of success fitting into so-called peer groups, developing their personal identities by trial and error.  Hopes and dreams for making a difference in the world extend far beyond youth, of course.  Many of us do not fulfill our desires and others’ expectations, and must learn to be thankful for whatever we have.  As they age, many find it necessary to calculate the energy we will need to give our full attention to the tasks before (another strange quark of attention) and what to put aside when running on fumes.

For any age, let’s not leave out the unfathomable attention quanta humankind expends on—to paraphrase Zora Neale Thurston—licking the pots in sorrow’s kitchen. Enduring physical pain, illness, disability, abuse, loneliness, trauma, shame and grief are as demanding in terms of attention as they are unavoidable to those afflicted. Oddly, those who suffer through such things are not precluded from moments of happiness as fine as any experienced outside sorrow’s kitchen.

The philosopher and mystic Simone Weil considered attention to be the purest form of prayer. She believed that “attention is the only faculty that gives us access to God.” Whether or not one believes in God, the power of attention is something undeniable in human experience and seems essential to any manifestation of love. There would be no works or art, scientific discoveries, technology, perseverance through hardships, heroism, civilization or survival of our species without it.

Science has not gone beyond the Big Bang theory of how our universe began 13.7 billion years ago, when there was a great burst of heat, light, energy and eventually matter. Only recently we’ve learned that visible matter, including us, is about 3.5 percent of the universe, whereas invisible or “dark” matter and energy constitutes all the rest. What are these unseen constituents?  We have no clue. All we know is that dark energy propels the universe to expand, while dark matter provides the gravity that keeps the stars, gas and dust in all the galaxies from flying apart.

Rovelli the physicist directs our attention to an amazing thought, that the flow of heat makes possible our experience of the passage of time. An attending metaphysician might extend this idea further: that the heat of which he speaks includes immeasurable quanta of attention. The energy source of this attention possibly connects us to that which brought our universe into existence and keeps it from dispersing into chaos.

How we experience time—and how we try to affect what is happening in present time—may determine whether our species will experience a future.

Rovelli’s book closes with a scientifically valid, hard-nosed assertion that our human species will probably not survive the damage we have already done to our environment. He hardly needs to exemplify this prediction with reference to global warming, widespread pollution, loss of habitat and mass extinction of other species due to our overuse of natural resources, and the extinction of earlier human species and civilizations.

It begs the question, in the most total way a species can beg:

Why can’t we apply more of our heat to the flow of time? Can we put enough attention into saving the biosphere so as not to destroy human civilization? Are we not capable of exerting more, stimulating more, innovating more, doing more of whatever it takes to save our future on this beautiful blue sphere on the outskirts of one galaxy among billions? What better goal would humankind have, exactly now?





  1. Having read the heat thing a bit more thoroughly, the first thing that comes up for me is pretty conventional. It’s the old “tree falling in the forest” question.
    How do we know that tree is cut down if there’s no one there to see it. Likewise, how do we know that time in any way connects with heat unless there’s a person or otherwise reliable observing entity there “attending” it? Is it not tautological to imply that, for there to be attention, it would first need to catch someone’s attention?

    Or maybe I’m missing something.

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