What if the universe, and all your memories, began five minutes ago?
Bertrand Russell pointed out in 1921 that no observation could ever rule out the universe having sprung into existence five minutes ago, complete with fully formed memories, worn shoes, and half-eaten breakfasts already in place. Nothing about the present moment can distinguish a world with a real past from one built only to look that way. The idea is now nicknamed Last Thursdayism, and it shows belief in the past rests on an assumption evidence can never fully confirm.