How can you possibly answer a broad question, "Tell me what you know.", without referring to any specific aspect of knowledge.
closed as too broad by virmaior, Mitch, Joseph Weissman♦ Oct 26 '17 at 12:41
Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
You can refer to the means of acquisition of knowledge: I know what I’ve directly experienced under suitable conditions and what I’ve learned through reliable testimony.