It occurs to me to devise mental tests on myself to see if I am who I think I am, but then I think, “I am who I think I am, or I probably am, and a test I conceive and answer about myself isn’t a way to test if I’m another person pretending to be me, because no matter how I answer I’ll answer like myself, thus falsely proving to myself that I am who I think I am.” No, what I need is for my clone to create and administer the test.