What is the 'key reminder' of the Bene Gesserit creed?

One of the central elements of the Bene Gesserit is their desire to achieve greatness and develop great projects. The key reminder is this difference between them, and the science of old. In the past, researchers would not have thought to embark upon projects spanning fifty lifetimes or more, but this is the central aim of the Bene Gesserit.