Shafer's theorem

Shafer's theorem explains how belief can be combined from different sources or evidence without overstating confidence. It shows that when merging uncertain information, the combined belief should respect the original beliefs and the uncertainty involved. Essentially, it provides a mathematical way to update and integrate different pieces of evidence, ensuring the resulting belief accurately reflects all available information. This theorem is foundational in theories of uncertainty and decision-making, helping to mathematically model how we can coherently aggregate multiple, possibly conflicting, pieces of evidence into a single rational belief.