All things flow. No man can ever step twice into the same river. How could he? The second time he tried to step, new waters would have flowed down from upstream: the water would not be the same. Neither would the bed and banks be the same, for the constant erosion would have changed them too. And if the river is the water, the bed, and the banks, the river is not the same river. Strictly speaking, there is no river. When common opinion names a river, it supposes that the name applies to something that will remain there for a time at least; but the river remains there no time at all. It has changed while we pronounce its name. There is no river. Worse yet, you cannot step into the same river twice because you are not there twice. You too change, and the person who stepped the first time no longer exists to step the second time. A person is also a river, a stream of consciousness, as William James called it; and the stream of consciousness never has the same contents, the same bed or banks. Persons do not exist.?