A drop of water is not immortal; it can be resolved into oxygen and hydrogen. If, therefore, a drop of water were to maintain that it had a quality of aqueousness which would survive its dissolution we should be inclined to be skeptical. In like manner we know that the brain is not immortal...
Why I Am Not a Christian: And Other Essays on Religion and Related Subjects (ed. Simon and Schuster, 1957) - ISBN: 9780671203238