sometimes, an idea "might" be true, but could never be demonstrated to be true, even in principle. for example, suppose some people believe that the earth and the universe came into existence last thursday. they claim that when the universe came into existence last thursday, it was created with the "appearance" of being many millions of years old. according to these believers, even our memories of two weeks ago are actually just the false memories that came along with the creation of the universe, which took place last thursday. such a belief is considered pseudoscientific because it is not falsifiable—no experiment could shed light on whether this belief is true or false.