In October 2012, I attended a lecture given by the Dalai Lama in a cavernous auditorium at the Massachusetts Institute of Technology. Even without words, the moment would have been profound: one of the world’s spiritual leaders sitting cross-legged in a modern temple of science. Among other things, the Dalai Lama spoke about śūnyatā, translated as “emptiness,” a central concept in Tibetan Buddhism. According to this doctrine, objects in the physical universe are empty of inherent and independent existence—all meaning attached to them originates in constructions and thoughts in our minds. As a scientist, I firmly believe that atoms and molecules are real (even if mostly empty space) and exist independently of our minds. On the other hand, I have witnessed firsthand how distressed I become when I experience anger or jealousy or insult, all emotional states manufactured by my own mind. The mind is certainly its own cosmos. As Milton wrote in Paradise Lost, “It [the mind] can make a heaven of hell or a hell of heaven.” In our constant search for meaning in this baffling and temporary existence, trapped as we are within our three pounds of neurons, it is sometimes hard to tell what is real. We often invent what isn’t there. Or ignore what is. We try to impose order, both in our minds and in our conceptions of external reality. We try to connect. We try to find truth. We dream and we hope. And underneath all of these strivings, we are haunted by the suspicion that what we see and understand of the world is only a tiny piece of the whole.
Modern science has certainly revealed a hidden cosmos not visible to our senses. For example, we now know that the universe is awash in “colors” of light that cannot be seen with the eye: radio waves and X-rays and more. When the first X-ray telescopes pointed skyward in the early 1970s, we were astonished to discover a whole zoo of astronomical objects previously invisible and unknown. We now know that time is not absolute, that the ticking rate of clocks varies with their relative speed. Such incongruities in the passage of time are unnoticeable to us at the ordinary speeds of our lives but have been confirmed by sensitive instruments. We now know that the instructions for making a human being, or any form of life, are encoded in a helix-shaped molecule found in each microscopic cell of our bodies. Science does not reveal the meaning of our existence, but it does draw back some of the veils.
The word “universe” comes from the Latin unus, meaning “one,” combined with versus, which is the past participle of vertere, meaning “to turn.” Thus the original and literal meaning of “universe” was “everything turned into one.” In the last couple of centuries, the word has been taken to mean the totality of physical reality. In my first essay, “The Accidental Universe,” I discuss the possibility that there may exist multiple universes, multiple space-time continuums, some with more than three dimensions. But even if there is only a single space-time continuum, a single “universe,” I would argue that there are many universes within our one universe, some visible and some not. Certainly there are many different vantage points. These essays explore some of the views, both the known and the unknown.