Persistence | The MIT Press
Another question is possible. What remains of the issues Professor Marie Kurtz poses when an 'elephant in the room' problem is raised?
The problem is that everything you and I know involves private experiences: My idea of you is a private experience. The idea of objects, the idea of objects' persistence spatially and temporally, conversations wherein we refer to common elements and mutual experiences, are private experiences.
Accordingly, if an adequate explanation of private experiences can be advanced, the Law of Parsimony and Occam's Razor would be on its side.
Any such explanations would also imply that arguments for subjective idealism (Bishop Berkeley's suggestion that the idea of an actual world is evidence that cost-saving move on God's part is working) or radical skepticism (I have no way of knowing whether I am imagining you, or whether I am anything more than a brain in a vat manipulated by aliens or Satan ).
A more provocative possibility exists! What has heretofore remained sacred is Descartes' claim: he exists because the fact of doubting guarantees the existence of at least one doubter. In other words, experiences of doubting and of being the cogito thinking or doubting, is also a private experience.
In short, the sceptical impulse has heretofore failed to take up the final challenge.