Born on This Day: January 18

French political philosopher whose analysis of separated powers profoundly influenced constitutional government.

British physician and scholar whose thesaurus created an enduring system for organizing English words by meaning.

American lawyer and statesman whose constitutional arguments and oratory shaped national political debate.

British-American psychologist who helped establish experimental psychology and professional training in the United States.

Austrian-Dutch physicist whose work clarified statistical mechanics and quantum theory and influenced a generation of physicists.

English author whose Winnie-the-Pooh stories became enduring works of children’s literature.

American entertainer and humanitarian whose international work for UNICEF helped popularize celebrity advocacy for children.