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New particles may yet be discovered, and even new laws. But it is almost taken for granted that everything from physics to biology, including the mind, ultimately comes down to four fundamental concepts: matter and energy interacting in an arena of space and time.

What makes “Mind and Cosmos” worth reading is that Dr. Nagel is an atheist, who rejects the creationist idea of an intelligent designer. The answers, he believes, may still be found through science, but only by expanding it further than it may be willing to go.

“Humans are addicted to the hope for a final reckoning,” he wrote, “but intellectual humility requires that we resist the temptation to assume that the tools of the kind we now have are in principle sufficient to understand the universe as a whole.”

There are only so many ways matter can arrange itself within that infinite universe. Eventually, matter has to repeat itself and arrange itself in similar ways. So if the universe is infinitely large, it is also home to infinite parallel universes.

Greene thinks the key to understanding these multiverses comes from string theory, the area of physics he has studied for the past 25 years. In a nutshell, string theory attempts to reconcile a mathematical conflict between two already accepted ideas in physics: quantum mechanics and the theory of relativity.

Instead of self-confident and self-centered answers, the author humbly asks fundamental questions: What is economics? What is its meaning? Where does this new religion, as it is sometimes called, come from? What are its possibilities and its limitations and borders, if there are any? Why are we so dependent on permanent growing of growth and growth of growing of growth? Where did the idea of progress come from, and where is it leading us? Why are so many economic debates accompanied by obsession and fanaticism?

The majority of our political parties act with a narrow materialistic focus when, in their programs, they present the economy and finance first; only then, somewhere at the end, do we find culture as something pasted on or as a libation for a couple of madmen.

most of them—consciously or unconsciously—accept and spread the Marxist thesis of the economic base and the spiritual superstructure.

Aristotelian thought had dominated mathematics and astronomy for centuries, until revolutionaries like Nicolaus Copernicus and Galileo Galilei challenged those views.

The mathematization of physics was a crucial step in the advancement of science. It was realized that the mathematical tools we had at the time weren’t strong enough.

By trial and error, Kepler worked and worked until finally, he hit upon the shape that worked—elliptical orbits with the Sun at one focus. It turned out to perfectly fit the known observations.

What, then, are you supposed to do when the mathematics gets more abstract? What do you do when you get to General Relativity, or Quantum Field Theory, or even more far afield into the speculative realms of cosmic inflation, extra dimensions, grand unified theories, or string theory? The mathematical structures that you build to describe these possibilities simply are what they are; on their own, they won't offer you any physical insights. But if you can pull out either observable quantities, or connections to physically observable quantities, that's when you start crossing over into something that you can test and observe.

Now, string theory (or, more accurately, string theories) have their own constraints governing them, as do the forces in our Universe, so it isn't provably clear that there's a one-to-one correspondence between our four-dimensional Universe with gravity, electromagnetism, and the nuclear forces and any version of string theory. It's an interesting conjecture, and it has found some applications to the real world: in the study of quark-gluon plasmas. In that sense, it's more than mathematics: it's physics. But where it strays from physics into pure mathematics is not yet fully determined.

If you describe the Universe precisely, and you can make quantitative predictions about it, you're physics. If those predictions turn out to be accurate and reflective of reality, then you're physics that's correct and useful. If those predictions are demonstrably wrong, you're physics that doesn't describe our Universe: you're a failed attempt at a physical theory. But if your equations have no connection at all to the physical Universe, and cannot be related to anything you can ever hope to someday observe or measure, you're firmly in the realm of mathematics; the divorce from physics will then be final. Mathematics is the language we use to describe physics, but not everything mathematical is physically meaningful. The connection, and where it breaks down, can only be determined by looking at the Universe itself.

“We are bathing in mystery and confusion on many subjects, and I think that will always be our destiny. The universe will always be much richer than our ability to understand it.”

In our recent On Being conversation, NASA astrophysicist and exoplanet researcher Natalie Batalha said something that stopped me up short: as sentient beings endowed with awareness, we are “the universe itself becoming aware.” Echoing poet Diane Ackerman’s lovely notion of “the plain everythingness of everything, in cahoots with the everythingness of everything else,” Dr. Batalha added: “It took 13.7 billion years for the atoms to come together to create the portal to the universe which is my physical self. So in that statement is this idea, or the fluidity of time and space. And I kind of see it all at once. And I don’t know what ‘me’ is. I just feel part of everything. And I feel such deep gratitude for being able to take this conscious look at the universe — at myself as being part of the universe.”

The challenges for alternative gravity theories—collectively known as modified Newtonian dynamics, or MOND—were spelled out in a separate preprint coincidentally published the day after the new model appeared. Chief among them is recasting the leading role dark matter plays in drawing the universe together, as described by a well-established cosmological model known as LCDM, or Lambda cold dark matter.

Simply put, LCDM says that we wouldn’t be here without dark matter. The infant universe was so smooth that the gravitational attraction of ordinary matter alone wouldn’t have been enough to gather particles into galaxies, stars, and planets. Enter dark-matter particles. Under the LCDM model, their collective bulk sculpts normal matter into the modern cosmic structures studied by astronomers.

LCDM became the standard model of cosmology in part because it so precisely agrees with the CMB. This map of the early universe shows almost imperceptibly thick and thin spots rippling through the cosmos. More recently, researchers have been able to measure the orientation or polarization of the CMB’s light more precisely. Any successful cosmology will need to establish a comprehensive history of the cosmos by reproducing these three observations: the CMB’s temperature, the CMB’s polarization, and the current distribution of galaxies and galaxy clusters.

In an academic career that included more than two decades as a professor in the philosophy department of the University of Toronto, following appointments at Cambridge and Stanford, Professor Hacking’s intellectual scope seemed to know no bounds. Because of his ability to span multiple academic fields, he was often described as a bridge builder.

“Ian Hacking was a one-person interdisciplinary department all by himself,” Cheryl Misak, a philosophy professor at the University of Toronto, said in a phone interview. “Anthropologists, sociologists, historians and psychologists, as well as those working on probability theory and physics, took him to have important insights for their disciplines.”

Professor Hacking wrote several landmark works on the philosophy and history of probability, including “The Taming of Chance” (1990), which was named one of the best 100 nonfiction books of the 20th century by the Modern Library.

“We’re used to thinking that information about an object — say that a glass is half full — is somehow contained within the object.” Instead, he says, entanglement means objects “only exist in relation to other objects, and moreover these relationships are encoded in a wave function that stands outside the tangible physical universe.”

Einstein, though one of the founders of quantum theory, rejected it, saying famously, God did not play dice with the universe.In a 1935 paper written with Boris Podolsky and Nathan Rosen, he tried to demolish quantum mechanics as an incomplete theory by pointing out that by quantum rules, measuring a particle in one place could instantly affect measurements of the other particle, even if it was millions of miles away.

Dr. Clauser, who has a knack for electronics and experimentation and misgivings about quantum theory, was the first to perform Bell’s proposed experiment. He happened upon Dr. Bell’s paper while a graduate student at Columbia University and recognized it as something he could do.

The fact is, we still don’t know what life is.

since the days of Aristotle, scientists and philosophers have struggled to draw a precise line between what is living and what is not, often returning to criteria such as self-organization, metabolism, and reproduction but never finding a definition that includes, and excludes, all the right things.

If you say life consumes fuel to sustain itself with energy, you risk including fire; if you demand the ability to reproduce, you exclude mules. NASA hasn’t been able to do better than a working definition: “Life is a self-sustaining chemical system capable of Darwinian evolution.”

As a neurosurgeon, I did not believe in the phenomenon of near-death experiences. I grew up in a scientific world, the son of a neurosurgeon. I followed my father’s path and became an academic neurosurgeon, teaching at Harvard Medical School and other universities. I understand what happens to the brain when people are near death, and I had always believed there were good scientific explanations for the heavenly out-of-body journeys described by those who narrowly escaped death.

In the fall of 2008, however, after seven days in a coma during which the human part of my brain, the neocortex, was inactivated, I experienced something so profound that it gave me a scientific reason to believe in consciousness after death.

All the chief arguments against near-death experiences suggest that these experiences are the results of minimal, transient, or partial malfunctioning of the cortex. My near-death experience, however, took place not while my cortex was malfunctioning, but while it was simply off. This is clear from the severity and duration of my meningitis, and from the global cortical involvement documented by CT scans and neurological examinations. According to current medical understanding of the brain and mind, there is absolutely no way that I could have experienced even a dim and limited consciousness during my time in the coma, much less the hyper-vivid and completely coherent odyssey I underwent.

Younger Democratic women are mostly for Bernie Sanders; older women lean more toward Hillary Clinton.

The idealistic but ungrateful naïfs who think sexism is a thing of the past and believe, as Mr. Sanders recently said, that “people should not be voting for candidates based on their gender” are seemingly battling the pantsuited old scolds prattling on about feminism

More time in a sexist world, and particularly in the workplace, radicalizes women.