Only the dead do not change, but their bodies are changed. The dead do not act, but are acted upon.
What people understand instinctively as animals is the terror of death. So we must often act not knowing whether we act in view of the truth or blind to it. Socrates said Knowledge is virtue. Whether I understand this correctly or not, it is certainly more easy to do good and do right with reason and true knowledge, while good is nearly impossible to do by accident out of ignorance. To say anyone must have certain knowledge in order to act is a death sentence. We will never know the truth, never know enough and yet still must act. In our actions we are helped by culture and morality. Culture is knowledge and morality is community. If we do well in the eyes of our community we at least have a legitimate defense of doing wrong in the eyes of the world.
Culture is the knowledge of community, and while progress still requires that ones culture be questioned if not rejected, still, health and survival and all those behaviors contributing to survival, and those behaviors counter to survival are in the book of culture. We may disagree, and we may see our culture in a different light, but raised in a certain culture we are never as subjects of it, capable of an objective judgment of it. It is what it is, and all of our knowedge not arrived at from individual experience is our culture.
So we can and must act though we do not know, and we can make ourselves more certain of our knowledge without the pretense of certainty.
Sweeney