In 1952, at the first World Humanist Congress, the founding fathers of IHEU agreed a statement of the fundamental principles of modern Humanism. They called it "The Amsterdam Declaration". That declaration was a child of its time: set in the world of great power politics and the Cold War.

At the World Humanist Congress in 2002, an updated Amsterdam Declaration 2002 was adopted.

The 16th World Humanist Congress unanimously agreed the following declaration formulated by Libre Pensee Francais. The Congress was held in Paris from 5th to 7th July 2005 to commemorate the Centenary of the French Law of Separation of Church and State of 9 December 1905.