The catalogue

Browse entries

Every entry identifies the former claim, the present understanding, why it changed, and the evidence supporting both sides of the history.

Earth Science Medicine

Not a fact anymore

Earth’s continents and ocean basins occupy essentially fixed positions.

What we know now

Earth’s rigid outer layer is divided into tectonic plates that move relative to one another. Continents form parts of these plates and are carried along as the plates move.

Status: Superseded
Category: Earth Science
Changed approximately: 1950s–1960s

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Not a fact anymore

Peptic ulcers are primarily caused by stress and lifestyle.

What we know now

Most peptic ulcers are caused by Helicobacter pylori infection or by certain medications, particularly nonsteroidal anti-inflammatory drugs (NSAIDs).

Status: Superseded
Category: Medicine
Changed approximately: 1982–1990s

Read the evidence →