The "Known-Unknown Matrix" template is a Design Thinking tool to explore a set of cognitive biases related to how we process our knowledge and make assumptions. It also might be used for brainstorm sessions when it is required to push the team into the Terra Incognita to explore opportunities outside of the current knowledge.
The rules for template are pretty simple:
KNOWN KNOWNS. List the arguments, ideas, properties, etc. about the subject that you think are absolutely true. These are your "stable" fundamentals.
KNOWLEDGE INVERSION. Challenge what you just have written. Are you sure these ideas are always true? Write down your doubts.
KNOWN UNKNOWNS. Explore the ideas you agree to continue challenging because you don't have a proof for, or because you don't have the answers to why it is actually true?
UNKNOWN KNOWNS. Explore the ideas you consider as common knowledge or true based on your experience. It includes things that just work, but you don't know why.
UNKNOWN UNKNOWNS. Explore here some of the fundamentals, that might be false in different conditions or from a different point of view. List here the things or findings that might flip you picture of the world.