What unique aspect of fingerprints did Sir Francis Galton establish regarding their nature?

Sir Francis Galton's work established the understanding that fingerprints are unique and persistent. He conducted extensive research into the minutiae of fingerprints and concluded that no two individuals possess identical fingerprints, even among identical twins. This is crucial in forensic science, as the uniqueness of fingerprints provides a reliable means of identification.

The term "persistent" refers to the fact that fingerprints remain largely unchanged throughout an individual's lifetime, barring any significant injury or medical condition that alters the skin. This characteristic ensures that fingerprints can be used consistently for identification, making them a cornerstone of forensic investigations.

This principle is foundational in fingerprint analysis, as it supports the use of fingerprint evidence in criminal cases, confirming identities and linking individuals to crime scenes or other relevant contexts. The uniqueness and permanence of fingerprints underpin their role in personal identification, making them an invaluable tool in law enforcement and forensic science.