Sagan believed that the scientific method, which is based on skepticism and the rigorous testing of hypotheses, was the best way to understand the world and make progress in knowledge. He also believed that skepticism was an important tool for evaluating claims and ideas, and that it was important to subject all claims to critical examination and to be open to the possibility that they may be wrong.

In his book "The Demon-Haunted World: Science as a Candle in the Dark," Sagan wrote:

"I have a foreboding of an America in my children's or grandchildren's time -- when the United States is a service and information economy; when nearly all the key manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what's true, we slide, almost without noticing, back into superstition and darkness."

Sagan's words remind us of the importance of maintaining a healthy skepticism and critical thinking, even in the face of powerful technological and social changes.