Philosophers have debated the nature of time since at least the 6th century B.C.E.

Time may be an emergent, rather than a fundamental, property of the universe

Some theories of everything—mathematical models that try to explain all aspects of the universe, including quantum phenomena and gravity—do not incorporate time. If a time-neglecting version of such a theory were ever validated, it might suggest that time is a feature that emerges from our limited perception of the universe.

Modern physics suggests that many universes with different physical laws could exist

Physicists suggest that quantum fluctuations in the early universe could have given rise to these universes. Ancient Greek philosophers like Chrysippus proposed a version of the multiverse over 2,000 years ago—millennia before its adoption into various theoretical frameworks today.

The origins of our fascination with time travel

Humans have been captivated by the prospect of leaping forward and backward in time for thousands of years. Georgia Institute of Technology Science Fiction Studies Professor Lisa Yaszek recounts how the concept has been utilized by storytellers from 400 BCE to modern-day to explore our relationship with the supernatural, technology, and the past. In a way, this historical recounting is a journey through time.

Humans have speculated about alien life since ancient times

Around 50 B.C.E., Roman poet and philosopher Lucretius shared the idea that alien life was possible, which was put forth by Greek philosopher Epicurus. The writing is believed to be the first straightforward assertion in Western literature that aliens must exist.

How philosophers have approached death throughout history

Philosophers often argue the counterintuitive view that there's actually nothing to fear about death. How do they come to this attitude of acceptance toward fate? This video articulates the views on death from Socrates, Epicurus, and Zhuangzi in a breezy, digestible way.

Friedrich Nietzsche theorized that we will live our lives over and over again: the myth of eternal recurrence

Rather than a theory of physics, the idea is designed as a moral argument. While Nietzsche famously eschewed the Christian afterlife, he wanted to avoid the nihilism that results from no longer having such an ultimate horizon. In a mystical moment, the philosopher came to believe that the fleeting moments of our lives would be repeated, presenting a test: would you want to relive this moment? If not, he would argue, you're not living well.

The quantum model of the atom resulted from over two millennia of scientific thinking

In 440 BCE, Democritus proposed that everything was made up of tiny particles surrounded by empty space, which varied in size and shape based on the substance's properties. It was not until the 20th century that experimental evidence validated elements of Democritus' model.

The hour originated from an ancient Egyptian astronomical system

The movements of astronomical objects, measured in a day and a year, form the foundation of our sense of time. The Egyptians divided each day and night into 12 time eras, using arbitrarily selected stars as references rather than movements of specific celestial objects.

For most of recorded history dreams were considered divine in origin

The first venture into modern dream interpretation may have been when ancient Greek philosopher Heracleitus proposed dreams were created within the mind. In the late 1800s, the rise of psychoanalysis theorized that dreams content revealed truths about one's psyche, while the invention of the electroencephalogram linked dreams to brain functions.

The ancient Greek philosopher who lived in a barrel

Out with green puppets living in trash cans, and in with ancient Greek philosophers living in barrels. This article details the life and beliefs of Diogenes the Cynic, a philosopher who reportedly lived in a barrel. According to this peer-reviewed article, it's unclear if Diogenes recorded any of his beliefs in writing. If he did, no texts have been recovered.

Chronobiologists study the effect of time on biological cycles

Circadian rhythms were first observed in the 1700s, when French astronomer Jean-Jacques D'Ortous de Mairan put a plant in a dark room and watched it still respond to day and night cycles, setting off further studies about specific light-dark biological cycles, an area of inquiry that continues today with the human "clock proteins" at the molecular level.

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.

Wilhelm Wundt's place in the history of psychology

While ancient philosophers considered the central problems of psychology, it was Wilhelm Wundt who first called himself one. Here's a quick video overview of his contribution.

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.

When Marcus Aurelius created endowed philosophy chairs in Athens

The Roman Emperor Marcus Aurelius is known as one of the most famous Stoic writers or thinkers, penning his classic opus ‘Meditations.’ In 176 CE, he endowed four philosophy chairs in Athens: one for Stoicism, and one for three of Stoicism’s rival schools: Aristotelianism, Platonism, and Epicureanism.

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...

'Others have seen what is and asked why. I have seen what could be and asked why not.'

- Pablo Picasso

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.

A timeline of the ancient Greeks

When exactly were the Ancient Greeks around on Earth? Their roots go back nearly 9,000 years to the Bronze Age with the so-called Minoan civilization. These sea-faring tribes would come together to hold off the invading Persian Empire and culminate in the glories of Athenian democracy, Spartan military discipline, and more. Check out this thorough timeline of the Ancient Greeks.

The ideas of Einstein and Freud combined in 'The Persistence of Memory'

The Persistence of Memory was painted on a canvas roughly the size of a sheet of paper, depicting a desolate landscape with melting clocks, ants, and a distorted figure. The piece incorporates Freud and Einstein's ideas, resulting in a haunting composition symbolizing time's fluidity and Dalí's personal anxieties.

The term “Middle Ages” was invented by Renaissance thinkers to belittle the era

The label “Middle Ages” reflects Renaissance writers’ admiration for ancient Greece and Rome, not medieval reality. They frame the post-Roman centuries as a cultural backslide—a view later reinforced by Edward Gibbon and modernized as the “Dark Ages” myth.

Color originates from the brain processing light of varying wavelengths

Various geometric models, including Newton's color circle of hue and saturation and the horseshoe-shaped XYZ space for mixing colors via vector mathematics, have been proposed to describe colors accurately. However, these models do not encapsulate the variety of psychological effects that cause perceived colors to differ from mathematical representations.

Imagining a fourth dimension

Famous astronomer Carl Sagan attempts to describe what it's like to think about the fourth dimension using the famous Flatland example from author Edwin Abbott in this classic video.

How upheavals in accepted scientific theories helped popularize the term 'paradigm'

When Thomas Kuhn published "The Structure of Scientific Revolutions" in 1962, he described the history of science as comprising periods of "normal science" where these accepted frameworks—paradigms—gradually accumulate anomalies until they cannot describe nature. Revolutionary science, such as the development of a new theory, results in a paradigm shift, another term Kuhn helped popularize. (Some readers may experience a paywall.)

What was the beef between Romanticism and the Enlightenment?

Would you embrace logic or lead with emotion? In the 18th century, Romanticism challenged the Enlightenment’s focus on reason, arguing that imagination, nature, and intuition held deeper truths. From literature to art, this movement reshaped culture—sparking a debate between order and passion.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Existentialist writer Jean-Paul Sartre coined the famous phrase 'Hell is—other people' in his play 'No Exit'

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

Trace how the Bill of Rights, inspired by centuries of political theory, took shape between 1774 and 1789.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

Massive blooms of microscopic plankton called dinoflagellates produce the neon blue light seen in glowing tides.

Famed poet TS Eliot rejected the manuscript for George Orwell's political fable 'Animal Farm,' writing that its criticism of authoritarianism was not 'the right point of view.'

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

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As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.

The most expensive ad of all time was for Chanel No. 5 perfume and cost roughly $33M to produce in 2004—about $57M in today's dollars.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.