A cornerstone of what we commonly agree on is that there must be a constant search for objective truth. We do not rely upon gods or other supernatural forces to solve our problems or provide guidance for our conduct. We rely instead upon the application of reason, the lessons of history, and personal experience to form an ethical/moral foundation and to create meaning in life.
Furthermore, we look to the methodology of science as the most reliable source of information about what is factual or true about the universe we all share, acknowledging that new discoveries will always alter and expand our understanding of it and perhaps change our approach to ethical issues as well. In any case our cosmic outlook draws primarily from human experiences and scientific knowledge.