We are biological creatures. We are born, we live, we die. There is no transcendent purpose to existence. At best we are creatures of reason, and by using reason we can cure ourselves of emotional excess. Purged of both hope and fear, we find courage in the face of helplessness, insignificance and uncertainty.

This quote is saying that people are born and will eventually die, and that there is no greater meaning or purpose to life. Instead, it suggests that people should use reason and logic to try to cope with difficult feelings of hopelessness and fear. This means that by looking at our emotions rationally and with detachment, we can find a sort of inner strength to deal with our insecurities and uncertainties about life.