n this moment of global crisis – when all future plans have seemingly been upended and the fragility of life illuminated with terrible clarity – there is much solace to be found in focusing on the present moment; meeting each day, each hour, each meal as it comes. Yet, in Brian Greene’s new book, Until the End of Time: Mind, Matter and Our Search for Meaning in an Evolving Universe, the theoretical physicist and author proposes that there is also a type of inner peace to be found by zooming out beyond this moment, this century, this millennium, back to the beginning of time and forward to the death of the universe. As well as offering lucid, detailed accounts of the science behind the big bang, the development of the cosmos, the emergence of life and human consciousness, and the inevitable extinction of the cosmos, Greene’s treatise is motivated by a personal search for equanimity. I recently spoke with the Columbia University professor about the consolations of a scientific perspective when confronting existential angst. You begin Until the End of Time by letting us into a desire that motivated you for a long time, which you describe as wanting to “catch a glimpse of the transcendent”. Was this search with you from childhood? Yes. And it came from an early recognition that we are not permanent, that we lead these finite lives, that we will all one day die. I think this realization hits kids in different ways. For me, it hit me in a sense where I wanted to be part of something that would be lasting, that would have a chance of being permanent. Why did you turn to math to find the answer? When I began to have this love of mathematics, it began to feel like this was the one thing in the world that you could really count on. Because once you prove a mathematical statement, it just is true forever, or so I thought. If much of your life was characterized by a desire to find permanence and meaning in math and physics, you describe in this book a moment of realization that everything, including math, is impermanent. Was this a difficult realization? Yes, absolutely. When I started using my understanding of physics to think about what the far future will be like, I began to realize everything, even mathematical truths, would at some level go away if there was no conscious being to reflect on them. And so that was a descent into darkness for me. But then you turned a corner while writing this book? Yes. In the very, very early stages of writing this book I just had this moment of clarity. Ultimately, I turned a sharp corner into a terrain that is very bright and very hopeful, which is the recognition of how utterly miraculous it is that we’re here at all. How utterly stunning it is that collections of particles can coalesce into things that think and feel and can create wonder and beauty and figure out deep mysteries. It was a real emotional shift. A question you pose in the book is: what is the best way to describe existence and reality? As a physicist, you say it is ultimately with reference to the physical laws of our universe. Does that mean you’re a reductionist? I am, but that term needs to be defined appropriately. My view is that reductionism gives you the undergirding for the fundamental ingredients and laws that underlie every process in the universe. But that doesn’t mean a reductionist framing is the right language for gaining insights into love and grief and aspiration and anxiety. Do I believe that those emotions and feelings reside upon the laws and the particles? I do. Do I think that the laws and particles provide the right language for deeply understanding those human qualities? I do not. We need to use the language that’s relevant to the kinds of questions that interest us. I enjoyed the chapter on the emergence of consciousness. As you make clear, the verdict is still out on what consciousness is, exactly. Do you have a preferred theory? The one that really seems most convincing to me at the moment comes from Michael Graziano at Princeton. He basically says whenever we engage with the world, our brain makes a schematic model of what’s happening in the world because it would burst at the seams if it had to include every single detail of everything that we encountered. So, we have these rough schematic models of everything that we encounter, including a rough schematic model of our own brain. Consciousness, he says, is nothing but the schematic representation that our brain holds of our own awareness. A fascinating and equally terrifying idea in the book is that consciousness and thought itself will eventually become physically impossible. What does this mean, exactly? The rough idea is that thought is itself a physical process that involves particles coursing through our brains. We know from the second law of thermodynamics that any physical process always generates a certain amount of heat, a certain amount of entropy, a certain amount of disorder. In the far future, the universe will not be able to absorb the heat produced by the very process of thought. So in that environment, any being that thinks one more thought will burn up in the entropic waste produced by the very process of thought itself. And at that point, thought will no longer be able to take place. It is this idea that brings you, at the end of the book, to consider human life, and indeed all life, as something that will end. I’m wondering how much room for doubt you leave, whether despite everything that human intelligence or any type of intelligence will prevail, nonetheless? Do I have some doubt? I have doubt about everything. In order for me to make headway on understanding the far future, I rely upon today’s laws of physics framed in the equations that we currently have at our disposal, and I allow for the possibility that in the far future those laws will change, and the math will change. And if things change sufficiently, then of course, I have left the possibility that the conclusions that I draw in the book would be affected.  So obviously, we’re in a time of discord and confusion and anxiety. What solace can people find in dwelling on these questions of eternity and the universe at a moment like this? Watching the news and hearing what’s happening and speaking to friends, I have that deep foreboding, I have that deep sense of tragedy that’s looming and growing by the hour and it is deeply painful. At the same time, I find it useful to take a big step back and see all that we encounter within this larger cosmological story that does go from the big bang and sweeps through today and on to what we could call eternity. And within that larger sweep, I do gain a certain kind of calmness, I do gain a certain kind of a footing that I have difficulty achieving when I’m solely focused on the moment to moment, the day to day.