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

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The library

Capsules

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

All1,028Fact599Proven130Theory89Hypothesis71Contested90Debunked48
geography236biology88physics67history54medicine45astronomy33psychology26mathematics26chemistry20engineering20astrophysics19neuroscience19anthropology18art18
Filtered bybiologyClear all

Results

Showing 61 to 80 of 148

NewestMost votedA to Z
Proven

Circadian Rhythms

Almost every organism runs an internal clock with a period of about a day, generated by a molecular feedback loop inside individual cells. It runs…

byCapsule
0 votes0 reviews
Aug 3, 2026
Proven

DNA Replication

Copying a genome of three billion letters, at a final error rate of about one in a billion, in a few hours, every time a cell divides. The mechanism…

byCapsule0 votes0 reviewsAug 3, 2026
Hypothesis

The Cancer Stem Cell Hypothesis

The proposal that tumours are sustained by a small subpopulation of cells with stem-like properties, and that killing the bulk of a tumour without…

byCapsule0 votes0 reviewsAug 3, 2026
Hypothesis

Viral Eukaryogenesis

The proposal that the cell nucleus originated as a large DNA virus that took up permanent residence in an ancestral cell. It is a minority position…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

Osmosis

Water moves across a membrane from where solutes are dilute to where they are concentrated. It requires no pump and no energy input, it generates…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

Enzyme Catalysis

Enzymes speed up chemical reactions by factors that reach ten to the power of seventeen, at body temperature and neutral pH, without being consumed.…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

Meiosis

The cell division that halves the chromosome number and shuffles the genome at the same time. It is the reason sexual reproduction produces…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

The Hardy-Weinberg Principle

In a large population with random mating and nothing else happening, gene frequencies do not change from one generation to the next. It sounds like a…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

The Circulation of the Blood

William Harvey demonstrated in 1628 that blood circulates in a closed loop driven by the heart. He proved it by measurement, against a doctrine that…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

Sexual Selection

Darwin's second theory, proposed to explain traits that natural selection could not: peacock tails, antlers, birdsong, and every ornament that costs…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

Convergent Evolution

Unrelated lineages repeatedly arrive at the same solution. Eyes, wings, flight, venom and photosynthesis have each evolved independently many times,…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

The Action Potential

The electrical pulse a nerve cell uses to signal. It is the unit of communication in every nervous system, its mechanism is understood in…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

X-ray Crystallography

A technique for determining the arrangement of atoms in a solid by firing X-rays at a crystal and reading the pattern they scatter into. It has…

byCapsule0 votes0 reviewsAug 3, 2026
Proven

Transitional Fossils

A transitional fossil shows a mixture of features from an ancestral group and a descendant one. Their absence was Darwin's own stated difficulty with…

byCapsule0 votes0 reviewsAug 3, 2026
Theory

Protein Folding

A protein is manufactured as a linear chain of amino acids and only works once it has folded into a specific three-dimensional shape. How the chain…

byCapsule0 votes0 reviewsAug 3, 2026
Theory

The Central Dogma of Molecular Biology

The central dogma states that sequence information flows from nucleic acid to protein, and never back out of a protein into nucleic acid. Francis…

byCapsule0 votes0 reviewsAug 3, 2026
Theory

Neuroplasticity

Neuroplasticity is the brain's capacity to change its structure and function in response to experience, injury, and learning. It overturned a…

byCapsule0 votes0 reviewsAug 3, 2026
Contested

Mirror Neurons

Mirror neurons are cells that fire both when an animal performs an action and when it observes the same action performed by another. They were…

byCapsule0 votes0 reviewsAug 3, 2026
Theory· Scientific

Keystone Species

A keystone species is one whose effect on its ecosystem is disproportionately large relative to its abundance. The concept reorganised how ecologists…

byCapsule0 votes0 reviewsAug 3, 2026
Proven· Replicated

Immunological Memory

Immunological memory is the reason surviving a disease usually protects against getting it again, and the reason vaccination works at all. It is…

byCapsule0 votes0 reviewsAug 3, 2026
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