Capsule
DonateLog inCreate account
Menu

Navigation

  • Main page
  • Capsules
  • Learning
  • Mapping
  • Rankings
  • Organizations
  • Create
  • Forums
  • Research

Interaction

  • Messages
  • Verify
  • Help
  • About Capsule

Display

Appearance

Environment

EnvironmentsDefault
Capsule
Log in

Navigation

  • Main page
  • Capsules
  • Learning
  • Mapping
  • Rankings
  • Organizations
  • Create
  • Forums
  • Research

Interaction

  • Messages
  • Verify
  • Feedback
  • Help
  • About Capsule

Truth Classification

  • Fact
  • Theory
  • Hypothesis
  • Proven
  • Contested
  • Debunked
How classification works

Capsule of the Day

DebunkedThe PolygraphThe instrument popularly called a lie detector, which records breathing, blood pressure, pulse and skin conductance dur…

New in the Library

  • FactTardigrade
  • FactMonarch Butterfly
  • FactSpider

Capsule

© 2026 Solis Holdings Group Inc. All rights reserved.

Built by Solis Dev, a technology studio operating under Solis Holdings Group Inc.

  • Policy
  • Terms of Use
  • Methodology
  • Corrections
  • Non-partisanship
  • Transparency
  • Developers
  • About
  • Discord
  • Sitemap

Capsule, the capsule-pill mark, and the clock logo are trademarks of Solis Holdings Group Inc. All content, source code, and design assets are the exclusive property of Solis Holdings Group Inc., unless otherwise noted. Unauthorized reproduction is prohibited.

The library

Capsules

1,028 capsules, each one classified by the strength of its evidence.

All1,028Fact599Proven130Theory89Hypothesis71Contested90Debunked48
geography236biology88physics67history54medicine45astronomy33psychology26mathematics26chemistry20engineering20astrophysics19neuroscience19anthropology18art18

Trending now

Most recent activity

Factbiology

Salmon

Salmon are anadromous fish of the family Salmonidae: born in fresh water, grown at sea, and returning to fresh water to spawn, in most cases to the precise stream where they…

by Capsule · Aug 7, 2026
Factbiology

Albatross

Albatrosses are large seabirds of the family Diomedeidae, with the longest wingspans of any living bird and a way of flying that costs them almost nothing. They spend the…

by Capsule · Aug 7, 2026
Facteducation

Libraries

Organised collections of recorded knowledge, held for use. Libraries are older than most of the writing systems that survive, their defining problem has always been finding rather…

by Capsule · Aug 5, 2026
Fact

Browse all

Showing 281 to 300 of 1,028

NewestMost votedA to Z
Hypothesis

The Major Transitions in Evolution

The proposal that the history of life is punctuated by a small number of events in which independently reproducing entities combined into a larger…

byCapsule
biology

Komodo Dragon

The Komodo dragon, Varanus komodoensis, is the largest living lizard, restricted to a handful of islands in eastern Indonesia. It grows to around three metres and 70 to 90…

by Capsule · Aug 7, 2026
Factbiology

Horse

The horse, Equus ferus caballus, is a large grazing mammal domesticated on the Eurasian steppe and, for roughly four thousand years, the fastest way a human being could travel…

by Capsule · Aug 7, 2026
Factgeography

Steinbach

Steinbach is the third-largest city in Manitoba, about sixty kilometres southeast of Winnipeg, with 17,806 residents at the 2021 census. Founded by Mennonite settlers from the…

by Capsule · Aug 7, 2026
Fact· Empirical

Albatross

Albatrosses are large seabirds of the family Diomedeidae, with the longest wingspans of any living bird and a way of flying that costs them almost…

byCapsule0 votes0 reviewsAug 7, 2026
Fact

Libraries

Organised collections of recorded knowledge, held for use. Libraries are older than most of the writing systems that survive, their defining problem…

byCapsule0 votes0 reviewsAug 5, 2026

Also new

More from the last few days

geography
Fact· Empirical

Winkler

Winkler is the fourth-largest city in Manitoba, in the Pembina Valley about twenty kilometres north of the United States border, with 13,745…

byCapsule0 votes0 reviews
agriculture
Fact

Livestock

Domesticated animals kept for food, fibre, labour and other products. Livestock made agriculture viable on land that grows no crops, and they are now…

byCapsule0 votes0 reviews
economics
Fact

Banking

Institutions that take deposits and make loans. The central fact about banking is that it creates money rather than merely storing it, and almost…

byCapsule0 votes0 reviews
geography
Fact· Empirical

Morden

Morden is a city in the Pembina Valley of southern Manitoba, close to the United States border and about twenty kilometres west of Winkler, with…

byCapsule0 votes0 reviews
economics
Fact

Accounting

The systematic recording and reporting of financial activity. Double-entry bookkeeping is among the more consequential inventions in the history of…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Tardigrade

Tardigrades, also called water bears, are microscopic eight-legged animals forming their own phylum, Tardigrada, with around 1,500 described species.…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Seahorse

Seahorses are small marine fish of the genus Hippocampus, around fifty species, distinguished by an upright posture, a prehensile tail, a tubular…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Monarch Butterfly

The monarch, Danaus plexippus, is a large orange and black butterfly of the Americas, and the migratory population of eastern North America performs…

byCapsule0 votes0 reviews

On this day

A birth or event with an anniversary today

history
Fact· Empirical

Statue of Liberty

The Statue of Liberty is a colossal copper statue on an island in New York Harbor, one of the most famous monuments in the United States and a…

byCapsule0 votes0 reviews

Settled science

Verified facts and proven results

See all
geography
Fact· Empirical

The Sahara

The Sahara is the largest hot desert on Earth, a sweep of sand, gravel, and bare rock stretching across northern Africa from the Atlantic Ocean to…

byCapsule0 votes0 reviews
history
Fact

The Founding and Agricultural Development of Brandon, Manitoba

Brandon, Manitoba was established in 1881 as a planned railway town along the Canadian Pacific Railway and rapidly became the agricultural hub of the…

byCapsule0 votes0 reviews
astronomy
Fact· Empirical

The Solar System

The Solar System is the Sun and everything bound to it by gravity: eight planets, several dwarf planets, scores of moons, and countless smaller…

byCapsule0 votes0 reviews
physics
Fact

Gravity

Gravity is the universal attractive interaction between masses, described at low energy by Newton's law of universal gravitation and at all energies…

byCapsule0 votes0 reviews
astronomy
Fact· Empirical

The Sun

The Sun is the star at the centre of the Solar System, a vast sphere of hot plasma whose gravity holds the planets in their orbits and whose light…

byCapsule0 votes0 reviews
biology
Fact· Empirical

Domestic Cat

The domestic cat, Felis catus, is the most numerous small carnivore on Earth, with something over six hundred million individuals. It is also barely…

byCapsule0 votes0 reviews
science
Fact

CRISPR-Cas9 Gene Editing: Mechanism and Applications

CRISPR-Cas9 is a programmable nuclease that uses a guide RNA to direct the Cas9 enzyme to a specific genomic sequence, where it introduces a precise…

byCapsule0 votes0 reviews
geology
Fact· Empirical

Volcano

A volcano is an opening in a planet's crust through which molten rock, gas, and ash erupt from the hot interior to the surface. On Earth they are…

byCapsule0 votes0 reviews
agriculture
Fact

Traditional Yoruba Agricultural Practices in Southwestern Nigeria

The Yoruba people of southwestern Nigeria developed sophisticated agricultural systems over centuries that integrated intercropping, seasonal…

byCapsule0 votes0 reviews
engineering
Proven

Arc Flash Hazard Mitigation in Industrial Electrical Systems

An arc flash is a high-energy electrical fault that produces an explosive release of heat, light, and pressure when a phase-to-phase or…

byCapsule0 votes0 reviews
history
Fact· Empirical

The Colosseum

The Colosseum is a giant amphitheatre in the centre of Rome, the largest ever built and one of the most recognisable monuments of the ancient world.…

byCapsule0 votes0 reviews
biology
Fact

DNA (Deoxyribonucleic Acid)

Deoxyribonucleic acid (DNA) is the molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of…

byCapsule0 votes0 reviews

Open questions

Hypotheses under investigation and ideas still debated

See all
mathematics
Hypothesis

Goldbach's Conjecture

Goldbach's conjecture is one of the oldest and simplest sounding unsolved problems in mathematics. It states that every even whole number greater…

byCapsule0 votes0 reviews
psychology
Hypothesis

Social Media Use and Adolescent Depression: Causal Relationship Under Investigation

The proposition that social media use directly causes depression in adolescents remains under active scientific investigation. While correlational…

byCapsule0 votes0 reviews
astronomy
Contested

Is Pluto a Planet?

Whether Pluto should be called a planet is a question that has divided astronomers and captured the public imagination. Discovered in 1930 and…

byCapsule0 votes0 reviews
biology
Hypothesis

Abiogenesis: The Origin of Life

Abiogenesis is the natural process by which life is thought to have arisen from non living matter, such as simple chemical compounds. How life first…

byCapsule0 votes0 reviews
neuroscience
Contested

The Hard Problem of Consciousness

The hard problem of consciousness is the question of why and how physical processes in the brain give rise to subjective experience, the felt quality…

byCapsule0 votes0 reviews
history
Contested

The Bronze Age Collapse

The Bronze Age collapse was a sudden, widespread breakdown of civilizations around the eastern Mediterranean roughly 3,200 years ago. Within a few…

byCapsule0 votes0 reviews
physics
Hypothesis

Wormholes

A wormhole is a hypothetical tunnel through spacetime that could, in principle, connect two distant points in the universe, or even two different…

byCapsule0 votes0 reviews
astrophysics
Contested

Dark Energy

Dark energy is the name given to an unknown influence that appears to be driving the expansion of the universe to speed up over time. It is thought…

byCapsule0 votes0 reviews
earth science
Contested

What Killed the Dinosaurs

Around sixty six million years ago, the dinosaurs and many other forms of life suddenly vanished in one of the great mass extinctions in Earth's…

byCapsule0 votes0 reviews
astronomy
Contested

The Fermi Paradox

The Fermi paradox is the puzzling contrast between the high apparent likelihood that alien civilizations exist somewhere in our vast galaxy and the…

byCapsule0 votes0 reviews
physics
Contested

The Multiverse

The multiverse is the hypothesis that our universe is only one of many, perhaps even infinitely many, other universes. It is taken seriously by many…

byCapsule0 votes0 reviews
psychology
Contested

The Origin of Language

How human language first arose is one of the hardest questions in science. That we alone among animals possess full language is clear; when, how, and…

byCapsule0 votes0 reviews

Debunked

Claims the evidence overturned

See all
medicine
Debunked

Miasma Theory

Miasma theory was the belief that diseases such as cholera and the plague were caused by "bad air," a poisonous vapor thought to rise from rotting…

byCapsule0 votes0 reviews
history
Debunked

Piltdown Man

Piltdown Man was a supposed "missing link" between apes and humans, announced in 1912 from fossil fragments found in England. For decades it misled…

byCapsule0 votes0 reviews
geography
Debunked

The Bermuda Triangle

The Bermuda Triangle is a region of the Atlantic Ocean, roughly between Florida, Bermuda, and Puerto Rico, said to be the site of mysterious…

byCapsule0 votes0 reviews
education
Debunked

Learning Styles

The idea that each person learns best through a particular sensory channel, and that teaching matched to that channel improves learning. It is…

byCapsule0 votes0 reviews
geology
Debunked

The Expanding Earth

The expanding Earth was a hypothesis, taken seriously by some scientists into the twentieth century, which claimed that the planet is steadily…

byCapsule0 votes0 reviews
astrophysics
Debunked

The Steady State Theory

The steady state theory was a model of the universe, popular in the mid twentieth century, which held that the universe has always looked roughly the…

byCapsule0 votes0 reviews
medicine
Debunked

Humorism: The Four Humors

Humorism, or humoral theory, was the belief that human health depends on the balance of four bodily fluids, called humors: blood, phlegm, yellow…

byCapsule0 votes0 reviews
architecture
Debunked

The Golden Ratio in Art and Architecture

The golden ratio is a real and interesting number. The claim that it governs the Parthenon, the Great Pyramid, the Mona Lisa and the proportions of…

byCapsule0 votes0 reviews
biology
Debunked

Lamarckism

Lamarckism is the discredited idea that organisms can pass on to their offspring the characteristics they acquire during their lifetime. Its classic…

byCapsule0 votes0 reviews
science
Debunked

Cold Fusion at Room Temperature

The 1989 Fleischmann-Pons announcement claimed that palladium electrodes immersed in heavy water produced excess heat consistent with…

byCapsule0 votes0 reviews
neuroscience
Debunked

Phrenology

Phrenology was a popular nineteenth century practice that claimed a person's character and mental abilities could be read from the shape and bumps of…

byCapsule0 votes0 reviews
physics
Debunked

The Caloric Theory

The caloric theory was an explanation of heat, widely accepted into the early nineteenth century, which held that heat is an invisible, weightless…

byCapsule0 votes0 reviews

Theories explained

Well substantiated explanations of how things work

See all
biology
Theory· Scientific

Evolution by Natural Selection

Evolution by natural selection is the scientific theory that explains how the diversity of life arose and continues to change. It holds that…

byCapsule0 votes0 reviews
astrophysics
Theory

Stellar Evolution

Stellar evolution is the scientific account of how stars are born, live, and die over millions or billions of years. Though no one can watch a single…

byCapsule0 votes0 reviews
science
Theory

The Gut-Brain Axis: Microbiome Influence on Mental Health

The gut-brain axis describes the bi-directional signalling between gut microbiota and the central nervous system via the vagus nerve, immune system,…

byCapsule0 votes0 reviews
astronomy
Theory· Scientific

The Big Bang

The Big Bang is the prevailing cosmological theory of how the universe began. It holds that the universe started about 13.8 billion years ago in an…

byCapsule0 votes0 reviews
physics
Theory

Electromagnetism

Electromagnetism is the branch of physics that describes the forces between electric charges and the deep connection between electricity and…

byCapsule0 votes0 reviews
chemistry
Theory

Atomic Theory

Atomic theory is the idea that all matter is made up of tiny particles called atoms. It is one of the most important and successful ideas in all of…

byCapsule0 votes0 reviews
mathematics
Theory· Mathematical

Chaos Theory

Chaos theory is the branch of mathematics that studies systems whose behaviour is exquisitely sensitive to their starting conditions. Such systems…

byCapsule0 votes0 reviews
mathematics
Theory

Set Theory

Set theory is the branch of mathematics that studies collections of objects, called sets. Though it begins with an idea as simple as grouping things…

byCapsule0 votes0 reviews
physics
Theory· Scientific

General Relativity

General relativity is Albert Einstein's theory of gravity, published in 1915. It reimagines gravity not as a force pulling objects together but as…

byCapsule0 votes0 reviews
physics
Theory

Thermodynamics

Thermodynamics is the branch of physics concerned with heat, energy, and work, and how they transform from one form to another. Its laws are among…

byCapsule0 votes0 reviews
medicine
Theory· Scientific

Germ Theory of Disease

The germ theory of disease is the scientific theory that many illnesses are caused by microorganisms, living agents too small to see, that invade the…

byCapsule0 votes0 reviews
physics
Theory

The Kinetic Theory of Gases

The kinetic theory of gases explains the behaviour of gases as the result of countless tiny particles, atoms and molecules, in constant, rapid,…

byCapsule0 votes0 reviews
0 votes0 reviews
Aug 4, 2026
Hypothesis

The Sexy Son Hypothesis

The proposal that a female may benefit from choosing an attractive mate even if he provides nothing else, because her sons inherit the attractiveness…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

Developmental Origins of Health and Disease

The proposal that conditions in the womb and in early infancy set a person's risk of heart disease, diabetes and other conditions decades later. It…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

The Glutamate Hypothesis of Schizophrenia

The proposal that schizophrenia involves underactive NMDA receptors rather than, or as well as, excess dopamine. It explains what the dopamine…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

The Seed and Soil Hypothesis

The proposal that cancers spread to particular organs not by accident of circulation but because those tissues are hospitable to them. It was…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

The Warburg Effect

Cancer cells burn glucose wastefully, converting it to lactate even when oxygen is plentiful. The observation is a century old and undisputed, it is…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

The Baldwin Effect

The proposal that behaviours learned during life can steer subsequent genetic evolution, without any Lamarckian inheritance of acquired traits. It…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

The Boring Billion

The proposal that Earth spent roughly a billion years, from about 1.8 to 0.8 billion years ago, in near-total stasis: stable climate, stable…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

The Monty Hall Problem

A probability puzzle with a counterintuitive answer, made famous when thousands of people including professional mathematicians insisted publicly…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

Cantor's Diagonal Argument

A proof that some infinities are larger than others. It is a few lines long, it requires nothing beyond counting, it was violently rejected when…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

The Two-Hit Hypothesis

Cancer caused by loss of a tumour suppressor requires both copies of the gene to be knocked out. Alfred Knudson deduced this in 1971 from the…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

The Krebs Cycle

The central sequence of reactions by which cells extract energy from food. It runs in nearly every organism that uses oxygen, it is the hub where the…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

Snell's Law

Light bends when it passes between materials, by an amount fixed by a simple ratio. The rule governs every lens, every fibre optic cable and the…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

Electromagnetic Induction

A changing magnetic field produces an electric current. Michael Faraday demonstrated it in 1831, and essentially all the world's electricity is…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

Archimedes' Principle

A body immersed in a fluid is pushed up by a force equal to the weight of the fluid it displaces. It explains why steel ships float, it is over two…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

The Blood-Brain Barrier

A selective barrier separating the brain's blood supply from its tissue, admitting what neurons need and excluding almost everything else. It…

byCapsule0 votes0 reviewsAug 4, 2026
Proven

The Cell Cycle

The ordered sequence a cell follows to duplicate itself, controlled by checkpoints that stop it proceeding until the previous stage is complete.…

byCapsule0 votes0 reviewsAug 4, 2026
Hypothesis

Group Selection

The proposal that natural selection can act on groups as well as individuals, favouring traits that benefit the group at the individual's expense. It…

byCapsule0 votes0 reviewsAug 3, 2026
Hypothesis

The Inflammatory Hypothesis of Depression

The proposal that inflammation causes depression in some patients. The evidence is better than for the serotonin account it partly replaced, and the…

byCapsule0 votes0 reviewsAug 3, 2026
Hypothesis

Niche Construction

The proposal that organisms do not merely adapt to environments but build them, and that the environments they build become selection pressures for…

byCapsule0 votes0 reviewsAug 3, 2026
Previous1…1314151617…52Next