If you try to enumerate all of the things that you know with absolute, 100% certainty, you will find that the list is very small. You know that “something” exists. If you have mental experiences, then you know that “you” exist (though coming up with a reasonable definition for what “you” means can be remarkably tricky). If your mental experiences are varied, then you know that whatever exists creates varied mental experiences. With some cleverness, you may be able to add to this list ...