Epistemology 101. A very simple question. Think of everything that you think you know. How do you know it? How? You are a repository of data and lore and myth and fact. Think of how many times during the day you refer to something that you know and that you remember. How do you know what you know? And there are things that you do that I’m sure you know are bad for you. If not, you’re not human. So the question becomes why don’t you do what you know? There are people who have such a strong faith system in religion and custom and “spirituality.” But if you want ask them how do they know this, they will look at you and say, “I know what I know.” Which begs the question: How do you know what you know?
Source