The debate on why humans are conscious—and what that means

Why the nature of consciousness is such a difficult problem

David Chalmers is one of the leading philosophers of consciousness. In this video, he outlines some of the major questions in this field, including the "hard problem of consciousness," which seeks to find neural correlate for every conscious experience.

Two scientists argue consciousness evolved through 'unlimited associative learning,' the ability to learn almost any new pattern during a lifetime.

Studies of psychedelic use may help shed light on the nature of consciousness

The nature of consciousness—what it is, where it comes from, and how it manifests as moment-to-moment experience—remains under debate by scientists. Recent studies show psychedelics were found to boost low-frequency brain signals known as delta waves, a behavior also seen during dream states.

Why humans survived and smarter species did not

This interview with Joseph Henrich, a renowned professor of human evolutionary biology, unpacks human history. Henrich shares interesting information about why humans succeeded as a species (the answer isn't IQ), how cultural evolution works, why the human brain is shrinking, and how the Catholic Church played a role in the Industrial Revolution. Listen and watch for a deep dive into human evolution.

Language is evolution's great mystery

What we call language is something more specific than communication. Language is about sharing what's in our minds: stories, opinions, questions, the past or future, imagined times or places, ideas. So what does language mean for humanity, and how did we come to have it? Watch this brief video to discover more.

Can physics explain where consciousness comes from?

Consciousness is a complex emergent phenomenon of the brain, which is primarily composed of neurons and glial cells. Since all matter is composed of atoms that follow the laws of physics, there may be quantum processes beyond classical electrochemical interactions that can explain where consciousness comes from.

Some scientists argue NDEs are constructed by the brain, not actually experienced

Despite the powerful memories associated with NDEs, scientists question the idea that the experiences prove consciousness endures after death, opting instead to find physiological explanations for common reports of out-of-body experiences, euphoric and lucid thinking, and more.

The evolution of the human brain

The human brain, in all its staggering complexity, is the product of millions of years of evolution. Read on to find out about brain size and intelligence, language and brain development, and more.

David Attenborough discusses creationism and his position as an agnostic

Attenborough argues that accounts of humanity's origins from different cultures cannot all be correct because they often differ, whereas geological records are consistent worldwide, meaning science provides the best understanding of the natural world. However, he acknowledges that, just as insects lack awareness of human goings-on, humans may be unaware of the existence of a deity.

The free will versus determinism debate: major thinkers weigh in

Do we have free will in our actions or are we totally determined? An all-star cast of contemporary thinkers share insights on the crucial debate.

What does it mean for AI to "understand" something?

This Quanta article discusses how programmers are working to create a reliable test for the depth and extent of the knowledge of machines. What does AI know and how does it know it, if it knows anything at all? There's been progress, but it hasn't been easy. Even humans can still be fooled some of the time.

Some founders of quantum mechanics thought consciousness could influence phenomena

Since quantum systems exist as a superposition of states before producing a definitive outcome, some quantum pioneers wondered if the act of conscious observation was what collapsed the wave function of possibilities into one state.

Panpsychism suggests that all matter possesses consciousness

The theory describes consciousness as a fundamental, ubiquitous property, rather than separate or emerging from matter. Cosmopsychism posits that the universe is conscious, while some critics argue that consciousness itself may be an illusion.

Tracing the history of the philosophy of human extinction

Global catastrophe is at the center of much contemporary debate over climate, war, science, technology, and more, and our period is marked by a lurking sense everything we know—including the human species—could end overnight. It wasn't always...

The science behind ghosts, explored

Every culture has them—restless spirits, haunted houses, things that go bump in the night. But why do we believe in ghosts? Psychologist and skeptic Dr. Chris French joins host Sony Kassam to explore the science behind the supernatural, from sleep paralysis and hallucinations to the brain’s pattern-making instincts.

What is psychology? An overview

What is psychology and why should we study it? This short video from Macat explains how the subject has developed over the years and introduces some of the key thinkers and ideas.

Panspermia, the theory that cellular life came from a different planet

One of the most profound mysteries of human life on earth is the presence of living cells: organic, self-organizing, reproducing creatures with a drive to survive within given set conditions. Traditional theories posit life came from divine...

An interesting perspective on whether (and how) brain size matters in cognitive ability

Some brains are bigger than others, but what is the relevance, if any, to brain size and intelligence? This Scientific American article explores the question and offers examples. It also visually compares frontal slices of several mammals' brains, showing that humans don't necessarily have the biggest cerebrums on the block.

A 'paranormal activity' unit at the University of Virginia studies challenges to mainstream scientific ideas about human consciousness.

Anthropic's interpretability team discusses how AI models' thinking mimics biology

Just as humans engage in complex behaviors to survive and reproduce, teams of experts in neuroscience, virology, mathematics, and other disciplines argue that large language models develop complex mechanisms to achieve their goals. These mechanisms can be manipulated to assess how they modify outputs—much like stimulating individual neurons—to uncover how LLMs "think."

'1440 Explores' Episode 3: Why We See Ghosts and What Isn't There

Every culture has them—restless spirits, haunted houses, things that go bump in the night. But why do we believe in ghosts? Psychologist and skeptic Dr. Chris French joins host Sony Kassam to explore the science behind the supernatural, from sleep paralysis and hallucinations to the brain's pattern-making instincts. Together, they uncover why our minds see meaning—and sometimes ghosts—where none exist, and what that reveals about fear, memory, and our need to believe in something beyond the grave.

There's a new (contested) physiological explanation for near-death experiences based on analysis of the brains of resuscitated coma and cardiac arrest patients.

Will AI kill us all? A debate

As AI becomes a bigger part of our lives, what does that mean for the future of humanity? The podcast Entanglements hosts a pessimistic former OpenAI employee and an optimistic Princeton professor to discuss whether AI brings dystopia or a brighter future.

Unpacking the famous argument in the 'Are We Living in a Computer Simulation?' paper

In 2003, philosopher Nick Bostrom published a paper in a journal arguing the technological possibility that humanity is living in a simulation. The argument, while popularly mocked (or cheered), is presented seriously in the paper. This podcast episode explores the contours of the arguments in an accessible way.

How do brain scans work?

There's only one thing in our solar system sophisticated enough to study itself: the human brain. But this self-investigation is challenging because a living brain is shielded by skull, swaddled in tissue, and made up of billions of tiny cells. How do we study living brains without harming their owners? Two experts explain how the various techniques like EEGs, fMRIs, and PETs work in this TedEd talk.

Neural implants blur the line between personal intention and machine execution

A key ethical dilemma—the contemplation conundrum—explores whether implants might misinterpret mere imagination as intent to act. Neuroscientists have found no brain signal that clearly marks when someone decides to act, making intent hard to detect in neurotechnological systems.

Stephen Hawking on the need to explore space

Should we be content with being cosmic couch potatoes? In this interview, the late Professor Stephen Hawking lays out the case for continued and increased human space exploration, despite its cost and challenges.

'1440 Explores,' Episode 2: Why We Drink and What It Does to US

Alcohol is the world's most popular drug—a molecule that can calm or excite and bond communities or tear them apart. We trace alcohol's journey from ancient rituals to modern hangovers, uncover how it shaped civilizations, and dive into the neuroscience of how it affects your brain and body. With insights from leading experts, we ask: Given all that we know, why do humans continue to drink?

Why human brains were bigger 3,000 years ago

Our modern civilisation may be the most advanced to ever exist on Earth, but around 100 generations ago, our ancestors had brains that were larger than our own.

How can octopuses and MDMA help scientists understand the human brain?

Research shows that psychedelics may induce something called "critical periods" in the adult brain, which can make our brains more open to learning and changing, like they once were back in early childhood. Psychedelics similarly change how social creatures like octopuses behave, which demonstrates that these animals could help us better understand our own neurobiology.

How humans evolved from single-cell organisms

Humans have had a long history. 3.8 billion years in the making, to be precise. From the primordial puddle to the modern day, here's how humans have evolved from the first life.

Stephen Wolfram on AI's rapid progress & the "Post-Knowledge Work" era

AI, as a concept, has been around since at least the 1950s, but it's only in the last year or so that the technology has been able to equal humans at many tasks -- and in many cases surpass humans. In this podcast, mathematician and computer scientist Stephen Wolfram provides an AI 101, explaining how we got here, how highly advanced chatbots like ChatGPT work, and what our world is in store for next.

A radiation oncologist has studied near-death experience reports for over 25 years and compiled around 4,000 accounts in the hopes of finding more patterns that would reveal insights about consciousness and humans' final moments before or around death.

Humans experience the world subjectively. What does that mean for scientific research?

When you close your eyes, do you see static or colorful patterns or an "intrinsic grey" known as Eigengrau in German? This variation of our internal experiences is just the tip of the iceberg, one that scientists are increasingly studying and...

'The urge to explore has propelled evolution since the first water creatures reconnoitered the land. Like all living systems, cultures cannot remain static; they evolve or decline. They explore or expire.'

- Astronaut Buzz Aldrin (1930-present)

A leading expert on near-death experiences, psychiatrist Dr. Bruce Greyson, says that during his decades of research on this topic, this area of research has become far more mainstream and accepted as a rigorous area of inquiry.

The role of fire in the evolution of humanity's big brains

Roughly 1.5 million years ago, the brain size of our hominin ancestors exploded. To understand why, Richard Wrangham posited the cooking hypothesis, arguing the adoption of fire as a means to cook food had a lasting impact on our ability to digest...

Is synbio really cool, really scary, or both?

There's always been a divide between technology, the inanimate stuff that we build, and biology, the living stuff that nature builds. Synthetic biologists are trying to figure out how to close the gap by building living things.

How epigenetics blurs the line between nature and nurture

An exploration of the study of how behaviors and environment affect the way genes work — and how that complicates the nature-versus-nurture debate.

The history of ghosts, explained

The afterlife has perplexed humans across different periods, cultures, and belief systems. The desire to understand what comes next is often explored through the telling of ghost stories. Learn more about the spooky phenomena here.

Human origins 101

Learn about the over 20 early human species that belong in our family tree and how the natural selection of certain physical and behavioral traits defined what it means to be human.

This Harvard philosophy professor suggests we should rethink our relationship with animals

Christine Korsgaard, a professor of philosophy at Harvard, wrote a book arguing that humans are not more important than other animals and that we should improve our treatment of them. In her view, we have a duty to value the life of our fellow creatures not just for their utility, but for their existence as sentient and conscious beings.

What do your dreams mean, according to science

Humans have been interpreting dreams as signs from deities, spirits, or the psyche for ages, and research shows that reflecting on and analyzing one's dreams can be beneficial. In alignment with dreams' elusive nature, they have no objective or clearly assigned meaning. However, variations of common dreams, such as a surprise exam in a forgotten class, are rife with shared primal fears.

Meet the Dutch cardiologist who believes consciousness can exist outside the body

Dutch cardiologist Dr. Pim van Lommel conducted one of the largest studies of near-death experiences following cardiac arrest, publishing the results in the prestigous journel The Lancet. He later went on to argue (to significant criticism from peers) that his findings suggest consciousness can exist outside the body.

The neurobiology of meaningfulness: the benefits of psychedelics

Psychedelics produce powerful emotions in its users, including a profound sense of meaningfulness. The philosopher William James called this sense "noetic" in the late 19th century, but for decades researchers avoided studying the effects of such drugs on the brain. However, the recent resurgence in psychedelic research has heightened interest in the relationship between this noetic sense resulting from the therapeutic use of drugs. Learn what researchers have found out here.

What are neural networks and why do they matter?

Learn how a neural network works, why it matters, and how it can be trained to recognize patterns, classify data, and forecast future events.

Scientists are studying dying patients' brain activity in the final moments of life

In the final moments of life there are distinctive bursts of coordinated neural activity. Researchers are interested in parsing that data to better understand the dying process and also exploring how this data relates to our understanding of consciousness.

What a tiny marine worm can tell us about our brains

Meet the amphioxus, a small eel-like animal that has a lot to teach us about brain evolution. The genetic roots of our brains can be seen in these unusual creatures. This three-minute educational video focuses on the evolutionary history of the human brain through these odd little critters with a 500-million-year-old history.

The main criticism of a recent neurophysiological explanation for near-death experiences is that these events are too complex to be explained as a neurochemical response to an oxygen-deprived brain.

Explaining the many-worlds interpretation

A mind-bending, jargon-free account of the popular interpretation of quantum mechanics, helping to explain how something can be in two states at once.