Many people have thought and expressed humanist ideas over many centuries all over the world, contributing to a humanist tradition. Though some of them may have believed in a god or gods, they were thoughtful, humane, open-minded people, and many of them fought against the ignorance and religious bigotry of their day, sometimes taking considerable personal risks to do so. Many of the great philosophers, scientists and moral thinkers were essentially humanist, because they did not accept traditional beliefs but thought for themselves and pushed human knowledge forwards.