Big Thinkers on Big Thinking


Sam Harris: The Self is an Illusion

Sam Harris describes the properties of consciousness and how mindfulness practices of all stripes can be used to transcend one's ego.

Ray Kurzweil: Your Thoughts Create Your Brain

The basic technologies to enable us to look inside the brain and see its functioning are growing exponentially. And they're at a point now where we can actually see individual interneural connections forming and firing.

You Are Not Your Brain, with Alva Noë

What's the Big Idea?


“Contemporary research on consciousness in neuroscience rests on unquestioned but highly questionable foundations. Human nature is no less mysterious now than it was a hundred years ago," writes philosopher Alva Noë in his book Out of Our Heads.

It's a bold assertion in an age when fMRI has enabled us to see images of the brain functioning in real time, and when many prominent public intellectuals (Stephen Hawking, Eric Kandel) have argued, either implicitly or vociferously, in favor of reductionism. The "brain-as-calculating machine" analogy assumes that human thought, personality, memory, and emotion are located somewhere in the gray matter protected by the skull. In other words, you -- at least, the waking you who gets out of bed in the morning -- are your brain. 

But you're not, says Noë. Just as love does not live inside the heart, consciousness is not contained in a finite space -- it's something that arises, something that occurs: a verb rather than a noun. And since the publication of Francis Crick's influential The Astonishing Hypothesis: The Scientific Search for the Soul, scientists have been looking for it in all the wrong places. Watch our video interview:


What's the Significance?

The evidence is this, says Noë: we still do not have an adequate theory for consciousness. "Everybody working in this field understands that we haven’t gotten to the stage even of having a back-of-the-envelope sketch of what a good neural theory of consciousness would look like. If I said to you, is consciousness happening in this individual cell?' you’d laugh."

A cell is obviously the wrong scale for explaining such a complicated phenomena. Neuroscientists have addressed this by simply expanding their domain: "You get bigger. You look at larger populations of cells and at the dynamic activity of those larger populations distributed in the brain spatially and over time."

What Noë is advocating is an entirely new approach -- what if we were to try expand our conception of consciousness by crossing that boundary out of the skull, to encompass "not just our bodies and our movements over time, but also the dynamic interactions that we have with the larger world around us, including the social world?"

Begin by looking at our connections, he says, and we'll find the tools for gaining insight into the nature of consciousness. In fact, lots of information that stimulates our nervous system doesn't get experienced by us. For example: "I might spend an hour talking to you and not notice what color your shirt is. In some sense I saw your shirt. It was there before me and it activated my nervous system and yet I might be unable in any way to make use of that information." It's an interesting puzzle: intuition structures our experience in a way that can't be traced back to the nervous system.

It's also an invitation to reopen an important debate that has been to some extent buried in a mire of specialization. It's okay to speculate, Noë seems to be saying, even if you're not a genius. The question is, will we do it?

Daniel Dennett on Reductio ad Absurdum, the Philosopher's Crowbar

With his new book "Intuition Pumps and Other Tools for Thinking," philosopher Daniel Dennett offers a kind of self-help book for deep thinkers -- a series of thought experiments designed as a workout for the deliberative mind. Here he discusses reductio ad absurdum, "the workhorse of philosophical argumentation," wherewith thinkers test the validity of an opponent's argument by taking it to its most illogical extreme.

Julia Galef on Bayes' Rule

Bayes’ Rule is a formalization of how to change your mind when you learn new information about the world or have new experiences.

Dan Harris: Hack Your Brain's Default Mode With Meditation

Dan Harris explains the neuroscience behind meditation, but reminds us that the ancient practice isn't magic and likely won't send one floating into the cosmic ooze. He predicts that the exercise will soon become regularly scheduled maintenance, as commonplace as brushing your teeth or eating your veggies. Harris, an ABC News correspondent, was turned on to mediation after a live, on-air panic attack. His latest book is 10% Happier: How I Tamed the Voice in My Head, Reduced Stress Without Losing My Edge, and Found Self-Help That Actually Works--A True Story.

Eric Kandel: Your Mind is Nothing but Neurons, and That's Fine

Nobel-Prize winning neuropsychiatrist Eric Kandel describes new research which hints at the possibility of a biological basis to the unconscious mind.

David Eagleman: Your Time-Bending Brain

Neuroscientist David Eagleman explains how your brain perceives time (retrospectively).

Consciousness: The Black Hole of Neuroscience

 What's the Big Idea?


“By the word ‘thought’ (‘pensée’) I understand all that of which we are conscious as operating in us.” –Renee Descartes

The simplest description of a black hole is a region of space-time from which no light is reflected and nothing escapes. The simplest description of consciousness is a mind that absorbs many things and attends to a few of them. Neither of these concepts can be captured quantitatively. Together they suggest the appealing possibility that endlessness surrounds us and infinity is within.

But our inability to grasp the immaterial means we’re stuck making inferences, free-associating, if we want any insight into the unknown. Which is why we talk obscurely and metaphorically about "pinning down" perception and “hunting for dark matter” (possibly a sort of primordial black hole). The existence of black holes was first hypothesized a decade after Einstein laid the theoretical groundwork for them in the theory of relativity, and the phrase "black hole" was not coined until 1968.

Likewise, consciousness is still such an elusive concept that, in spite of the recent invention of functional imaging - which has allowed scientists to visualize the different areas of the brain - we may not understand it any better now than we ever have before. “We approach [consciousness] now perhaps differently than we have in the past with our new tools," says neuroscientist Joy Hirsch.

"The questions [we ask] have become a little bit more sophisticated and we’ve become more sophisticated in how we ask the question," she adds - but we're still far from being able to explain how the regions of the brain interact to produce thought, dreams, and self-awareness. “In terms of understanding, the awareness that comes from binding remote activities of the brain together, still remains what philosophers call, ‘The hard problem.'"

What's the Significance?

 Discovering how mechanistic processes work - the firing of neurons or the earth revolving around the sun, for example - is considered by some to be an "easy" problem because it involves observation, the description of an event from a third person point of view. "Hard" problems, on the other hand, involve first person experience. They're the questions that persist even after physical processes have been mapped and explained.

It's tempting to see them as universal to humanity, but whether and how they've been framed has varied historically. Historians of philosophy have observed there was no ancient Greek word that corresponds to “consciousness," while the modern Western perspective on consciousness seems to have been developed during the Reformation era - the age of “I think, therefore I am,” and “To be or not to be.” (Hamlet was written around 1600, and Rene Descartes’ Discourse on the Method was published in 1637.)

So there's no reason to assume that consciousness is eternally inexplicable. However, it may never be explained through neurobiology, says David Chalmers, the philosopher who originally made the distinction. "In so many other fields physical explanation has been successful… but there seems to be this big gap in the case of consciousness," he says. "It’s just very hard to see how [neurological] interactions are going to give you subjective experience."

 Hirsch sees it more practically. Though functional imaging has not explained where perception comes from, it has important applications for unconscious patients. “The boundaries have been broken a little bit, clinically," she says. "As we study patients with disorders of consciousness, we can probe their levels of awareness in ways that other traditional ways of asking them to respond."

It's no different than any other aspect of the brain that we cannot presently explain, she says:

For example, we don’t understand how the brain creates colors. That’s a perception that is very private - I don’t know that your perception of blue is like my perception of blue, for example. Smells are another one. I don’t know that your perception of the smell of an orange is like mine. These are the hard problems of neuroscience and philosophy that we haven’t made a great deal of progress on.

What do you think? Is the distinction between "hard problems" and "soft problems" useful, or reductive? Does the brain create consciousness? Will we ever empirically understand where it comes from or how it works?

Daniel Kahneman: Moving to California Won't Make You Happy

In some crucial areas of human cognition, we don’t know and we can’t fully trust ourselves. On the bright side, Daniel Kahneman’s work shows that the kinds of errors we tend to make are extremely predictable.

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  • Conflict and violence cost the world more than $14 trillion a year.
  • That's the equivalent of $5 a day for every person on the planet.
  • Research shows that peace brings prosperity, lower inflation and more jobs.
  • Just a 2% reduction in conflict would free up as much money as the global aid budget.
  • Report urges governments to improve peacefulness, especially amid COVID-19.

What is the price of peace?

Or put another way, how much better off would we all be in a world where armed conflict was avoided?

Around $14.4 trillion in 2019, according to the Institute for Economics and Peace (IEP) which crunched the numbers. That's about $5 a day for every person on the planet.

To give some context, 689 million people - more than 9% of the world's population - live on less than $1.90 a day, according to World Bank figures, underscoring the potential impact peace-building activities could have.

Just over 10% of global GDP is being spent on containing, preventing and dealing with the consequences of violence. As well as the 1.4 million violent deaths each year, conflict holds back economic development, causes instability, widens inequality and erodes human capital.

Putting a price tag on peace and violence helps us see the disproportionately high amounts spent on creating and containing violent acts compared to what is spent on building resilient, productive, and peaceful societies.
—Steve Killelea, founder and executive chairman, Institute for Economics & Peace (IEP)

The cost of violence


In a report titled "The Economic Value of Peace 2021", the IEP says that for every death from violent conflict, 40 times as many people are injured. The world's 10 most affected countries are spending up to 59% of their GDP on the effects of violence.

Grounds for hope

But the picture is not all bleak. The economic impact of violence fell for the second year in a row in 2019, as parts of the world became more peaceful.

The global cost dropped by $64 billion between 2018 and 2019, even though it was still $1.2 trillion higher than in 2012.

In five regions of the world the costs increased in 2019. The biggest jump was in Central America and the Caribbean, where a rising homicide rate pushed the cost up 8.3%.

Syria, with its ongoing civil war, suffered the greatest economic impact with almost 60% of its GDP lost to conflict in 2019. That was followed by Afghanistan (50%) and South Sudan (46%).

The report makes a direct link between peace and prosperity. It says that, since 2000, countries that have become more peaceful have averaged higher GDP growth than those which have become more violent.

"This differential is significant and represents a GDP per capita that is 30% larger when compounded over a 20-year period," the report says adding that peaceful countries also have substantially lower inflation and unemployment.

"Small improvements in peace can have substantial economic benefits," it adds. "For example, a 2% reduction in the global impact of violence is roughly equivalent to all overseas development aid in 2019."



Equally, the total value of foreign direct investment globally only offsets 10% of the economic impact of violence. Authoritarian regimes lost on average 11% of GDP to the costs of violence while in democracies the cost was just 4% of GDP.

And the gap has widened over time, with democracies reducing the cost of violence by almost 16% since 2007 while in authoritarian countries it has risen by 27% over the same period.

The report uses 18 economic indicators to evaluate the cost of violence. The top three are military spending (which was $5.9 trillion globally in 2019), the cost of internal security which makes up over a third of the total at $4.9 trillion and homicide.

Peace brings prosperity

The formula also contains a multiplier effect because as peace increases, money spent containing violence can instead be used on more productive activities which drive growth and generate higher monetary and social returns.

"Substantial economic improvements are linked to improvements in peace," says the report. "Therefore, government policies should be directed to improving peacefulness, especially in a COVID-19 environment where economic activity has been subdued."

The IEP says what it terms "positive peace" is even more beneficial than "negative peace" which is simply the absence of violence or the fear of violence. Positive peace involves fostering the attitudes, institutions & structures that create and sustain peaceful societies.

The foundations of a positively peaceful society, it says, are: a well functioning government, sound business environment, acceptance of the rights of others, good relations with neighbours, free flow of information, high levels of human capital, low levels of corruption and equitable distribution of resources.

The World Economic Forum's report Mobilizing the Private Sector in Peace and Reconciliation urged companies large and small to recognise their potential to work for peace quoting the former Goldman Sachs chair, the late Peter Sutherland, who said: "Business thrives where society thrives."

Reprinted with permission of the World Economic Forum. Read the original article.

  • One especially mysterious thing about the asteroid impact, which killed the dinosaurs, is how it transformed Earth's tropical rainforests.
  • A recent study analyzed ancient fossils collected in modern-day Colombia to determine how tropical rainforests changed after the bolide impact.
  • The results highlight how nature is able to recover from cataclysmic events, though it may take millions of years.

About 66 million years ago, a massive asteroid slammed into present-day Chicxulub, Mexico, triggering the extinction of dinosaurs. Scientists estimate the impact killed 75 percent of life on Earth. But what's remained more mysterious is how the event shaped the future of plant life, specifically tropical rainforests.

A new study published in Science explores how the so-called bolide impact at the end of the Cretaceous period paved the way for the evolution of our modern rainforests, the most diverse terrestrial ecosystems on Earth.

For the study, researchers analyzed thousands of samples of fossil pollen, leaves, and spores collected from various sites across Colombia. The researchers analyzed the samples to determine which types of plants were dominant, the diversity of plant life, and how insects interacted with plants.

All samples dated back to the Cretaceous-Paleogene boundary, some 70 million to 56 million years ago. Back then, the region's climate was mostly humid and hot, as it is today. However, the composition and structure of forests were quite different before the impact, according to the study results.

Tropical jungle Tropical jungle with river and sun beam and foggy in the gardenSASITHORN via Adobe Stock

For one, the region's rainforests used to have a roughly equal mix of angiosperms (shrubs and flowering trees) and plants like conifers and ferns. The rainforests also had a more open canopy structure, which allowed more light to reach the forest floor and meant that plants faced less competition for light.

What changed after the asteroid hit? The results suggest the impact and its aftermath led to a 45 percent decrease in plant diversity, a loss from which the region took about 6 million years to recover. But different plants came to replace the old ones, with an increasing proportion of flowering plants sprouting up over the millennia.

"A single historical accident changed the ecological and evolutionary trajectory of tropical rainforests," Carlos Jaramillo, study author and paleopalynologist at the Smithsonian Tropical Research Institute in Panama City, told Science News. "The forests that we have today are really the by-product of what happened 66 million years ago."

Today's rainforests are significantly more biodiverse than they were 66 million years ago. One potential reason is that the more densely packed canopy structure of the post-impact era increased competition among plants, "leading to the vertical complexity seen in modern rainforests," the researchers wrote.

The extinction of long-necked, leaf-eating dinosaurs probably helped maintain this closed-canopy structure. Also boosting biodiversity was ash from the impact, which effectively fertilized the soil by adding more phosphorus. This likely benefited flowering plants over the conifers and ferns of the pre-impact era.

In addition to unraveling some of the mysteries about the origins of South America's lush biodiversity, the findings highlight how, even though life finds a way to recover from catastrophe, it can take a long time.

    • A first-of-its-kind study examines the number of mothers who have lost a child around the world.
    • The number is related to infant mortality rates in a country but is not identical to it.
    • The lack of information on the topic leaves a lot of room for future research.

    Among the best indicators of societal progress over the last few decades has been the remarkable decline in infant and child mortality rates worldwide. In the early sixties, a staggering 1 in 4 children around the world died. Today, that rate has fallen to fewer than 1 in 10. The continued efforts of several organizations will help that number to fall even further.

    However, like many other kinds of progress, the blessings of these advances have been shared unequally. Child mortality rates are much higher in some parts of the world than in others. Additionally, measuring infant mortality by itself doesn't tell the whole story. While conditions are improving, the legacy of high child mortality rates endures.

    In hopes of shedding light on both issues, a first-of-its-kind study suggests that mothers in some parts of the world remain astronomically more likely to lose a child than others.

    Bereavement around the world

    An international team of researchers led by Dr. Emily Smith-Greenaway examined data from 170 countries. By combining information on child mortality, maternal life expectancy, the fertility rate, and the proportion of women in the country who have children, among other statistics, the researchers were able to create indices of the number of mothers per thousand who lost a child either before the age of one or five, or ever, for nearly every country in the world.


      Cumulative prevalence of infant mortality for mothers age 20–44. Notice the groupings of countries at both the high and low ends of the scale. (scale is per thousand) USC Dornsife College of Letters, Arts and Sciences

      The results are quite shocking.

      As seen in the above map, the countries with the highest maternal bereavement rates are clustered in sub-Saharan Africa and the Middle East. Hong Kong has the lowest maternal bereavement rate of any measured locale in the world at 2.8 per 1000, while Sierra Leone has the highest at 303.3 per 1000, nearly 1 in 3. A mother in Sierra Leone is 108 times more likely to have lost a child than a mother in Hong Kong.

      This difference is far larger than that of infant mortality alone. There are many possible reasons for this, including factors which directly impact child mortality. Because of the number of factors involved, there are countries where the infant mortality rate remains stubbornly high but where maternal bereavement is rather low, such as the Philippines, and countries where a low mortality rate hides a high bereavement rate, such as Peru.

      The differences between countries continue to exist when age is accounted for. While rates are worse everywhere when looking only at older mothers, the difference between Hong Kong, which remains the best, and Liberia, which becomes the worst, is still a factor of 70.


      Cumulative prevalence of infant mortality for mothers age 45–49. Notice the similarities with the above map. (scale is per thousand) USC Dornsife College of Letters, Arts and Sciences

      The mental and physical toll of losing a child

      The authors of the study suggest that these numbers demonstrate the existence of a previously hidden element of global health and the inequality between nations. Their work shows that the maternal cumulative prevalence of infant mortality is not identical to the infant mortality rate, though it is related. They also warn that their estimates are probably conservative due to the likelihood of unreported infant deaths.

      The toll of losing a child on a mother's mental and physical health is considerable. However, much of the research on this topic ignores the possible effects on other family members. The authors note that what information does exist suggests it can be equally as damaging to them. Additionally, they state that their research focused on national rates but that similar issues may exist within nations where demographic differences in infant mortality and parental bereavement rates exist. They encourage further study into this matter.

      Dr. Smith-Greenaway explained the authors' hopes for the study and the new area of research it identifies:

      "We hope that this work will emphasize that further efforts to lower child deaths will not only improve the quality and length of life for children across the globe, but will also fundamentally improve the lives of parents."

      • Researchers studied strategies that could deflect a large asteroid from hitting Earth.
      • They focused on the effect of detonating a nuclear device near an asteroid.
      • Varying the amount and location of the energy released could affect the deflection.

      Large asteroids don't tend to hit Earth very often. But when they do, major cataclysms result. Remember the dinosaurs?

      Add to this the fact that since 1998, scientists have detected about 25,000 near-Earth asteroids, while in 2020 alone, a record 107 of them came closer to our planet than the distance to the moon. With so many asteroids floating by, protecting our planet from impacts by these giant space bodies is an existential priority.

      To prepare for the day when an asteroid will be heading our way, a joint study published in Acta Astronautica from the Lawrence Livermore National Laboratory (LLNL) and the Air Force, looked at how to use neutron energy output from a nuclear blast to deflect such a threat.

      The scientists devised sophisticated computer simulations to compare strategies that could divert an asteroid 300 meters in diameter. In particular, they aimed to identify the effects of neutron energies resulting from a nuclear "standoff" explosion on the space rock's path. (A standoff detonation involves detonating a nuclear device near a space object — not on its surface.) The goal would be to deflect the asteroid rather than blow it up.


      Detonating a nuclear device near an asteroid deposits energy at and below the surface.Credit: Lawrence Livermore National Laboratory


      The researchers understood that they could affect an asteroid's path by changing the distribution and strength of the released neutron energy. Directing the energy could influence how much melted and vaporized debris could be created and its speed, which in turn would alter the asteroid's velocity. As the authors write in the paper, "Changing the neutron energy was found to have up to a 70% impact on deflection performance."

      The scientists see their work as a stepping stone in continuing research into how best to protect our planet. They plan to devise further simulations in order to comprehend more precisely the energy spread needed for the deflection strategy to work.

      Lansing Horan IV led the research, while getting a nuclear engineering master's degree at the Air Force Institute of Technology (AFIT) in a program with LLNL's Planetary Defense and Weapon Output groups. Horan explained that their team decided to zero in on neutron radiation from a nuclear blast because neutrons are more penetrating than X-rays.

      "This means that a neutron yield can potentially heat greater amounts of asteroid surface material, and therefore be more effective for deflecting asteroids than an X-ray yield," he shared.

      Another possible strategy for getting rid of an asteroid threat would be through so-called disruption. It essentially involves blowing the asteroid up, breaking it into tiny fast-moving pieces. Most of these shards should miss the Earth but around 0.5% could make it to the surface. The strategy does seem to have some drawbacks, however, if a larger asteroid came close to Earth. Exploding something like that could create a significant amount of calamity for the planet even if the whole asteroid didn't graze us.

      Horan thinks disruption may be more appropriate as a last-minute tactic "if the warning time before an asteroid impact is short and/or the asteroid is relatively small."

      Deflection is ultimately safer and less likely to produce negative consequences as it involves a smaller amount of energy than it would take to explode it. Horan said that over time, especially if we detect and deflect asteroids years before impact, even small changes in velocity should make them miss Earth.

      While some may be understandably worried about using nuclear blasts close to Earth, Hogan sees it as something that may have to be considered in situations when time is of the essence.

      "It is important that we further research and understand all asteroid mitigation technologies in order to maximize the tools in our toolkit," Horan elaborated. "In certain scenarios, using a nuclear device to deflect an asteroid would come with several advantages over non-nuclear alternatives."

      One such scenario would be if there's not enough warning and the approaching asteroid is large. In that case, a nuclear detonation might be "our only practical option for deflection and/or disruption," proposed the scientist.

      • Researchers from the Norwegian University of Science and Technology investigate the degree to which regret regarding sexual encounters makes us modify our behavior.
      • Women more often have regrets about encounters that occurred, while men regret the ones that didn't.
      • According to the study, people keep doing what they've been doing and continue to have the same regrets.

      When it comes to sexual encounters, both women and men may be left with feelings of regret in the fading afterglow. Women, according to recent research, are more likely to experience "action regret," wishing they hadn't had sex. Men, on the other hand, are more likely to report "inaction regret" if they feel they've passed up on a sexual opportunity.

      Both may experience regret, says a new study, but not so much that it changes their behavior going forward.

      Speaking to Norwegian SciTech, the lead author of the study, Leif Edward Ottesen Kennair of Norwegian University of Science and Technology (NTNU), says, "For the most part, people continue with the same sexual behavior and the same level of regret."

      The evolutionary value of emotion

      Credit: Morgan Lane/Unsplash


      "We wanted to examine if their level of regret contributed to a change in behavior the next time around," says senior author Mons Bendixen, who collaborated with Kennair and postdoctoral fellow Trond Viggo Grøntvedt.

      Explains Kennair, "A lot of emotions are functional, like disgust that protects against infection and fear that protects against danger. An evolutionary approach has helped us understand anxiety by understanding the function of fear: fight-flight-freeze is about avoiding danger and defending ourselves against it."

      The authors say that psychologists generally assume that emotions such as regret serve an evolutionary purpose — they keep us from repeating undesirable behavior.

      "Researchers," says Grøntvedt, "have found that most people believe this is true for regret. They assume that regret is actually a helpful negative feeling. People assume it guides them not to repeat what they regretted."


      The flexibility of regret

      Credit: Priscilla Du Preeze/Unsplash


      To see if sexual regret does actually change people's behavior, the researchers invited NTNU students to complete an anonymized web questionnaire about sexual regret. Prospective participants were told:

      "We invite you to participate in a research project that examines students' thoughts and feelings after having had casual sex (intercourse), and what factors that may affect these… Some of the questions are sensitive and relate to sexual acts and choices you may have made. Responding may cause some discomfort and embarrassment, and we recommend that all participants sit in an uninterrupted location when answering the questions."

      Individuals who agreed to participate were asked to fill out the survey two times, 4.5 months apart. The volunteers were between 18 and 30 years of age. For the first pass at the questionnaire, 529 students, 63.2 percent of whom were female, participated. Just 283 people completed the questionnaire both times.

      The questionnaire revealed a resounding, "Nope!" Four and a half months later, individuals had continued to hook up or not hook up in the same way they had at the start of the study. They also exhibited the same level of regret.


      Credit: Phix Nguyễn/Unsplash


      Kennair admits, "We are not that surprised. If regret helped, would not most sinners eventually become saints? What do you regret the most often? Has it changed your behavior?"

      The researchers suggest that, as they suspected at the outset of the project, regret is an emotion that's adaptive, with its impact on behavior dependent on context. In the case of sexual regret, there may be a disconnect between what we think we should want and what we really want.

      It may also be that habit simply overpowers regret. Previous studies have found that habits create ever-stronger neural pathways — it's why people often repeat mistakes. The idea is that making a mistake a first time creates a neural pathway to which we increasingly and unconsciously gravitate each time we repeat the error.

      Don't over-regret

      Kennair cautions, however, against getting too hung up on sexual regrets.

      "And yet," he says, "there are some folks who think that depressive ruminating and worry are a good idea. But the way we treat depression and generalized anxiety disorders is by helping people to stop ruminating and to stop worrying. Not everything people do, think or feel is an evolutionary adaptation — sometimes it is not appropriate either."