The whole universe is one. There is only one Self in the universe, only One Existence, and that One Existence, when it passes through the forms of time, space, causation, is called by different names, buddhi, fine matter, gross matter, all mental and physical forms. Everything in the universe is that One, appearing in various forms. When a little part of it comes, as it were, into this network of time, space and causation, it takes forms. Take off the network, and it is all one.
Swami VivekanandaThe body and mind are continually changing, and are, in fact, only names of series of changeful phenomena, like rivers whose waters are in a constant state of flux, yet presenting the appearance of unbroken streams. Every particle in this body is continually changing; no one has the same body for many minutes together, and yet we think of it as the same body.
Swami Vivekananda