Heaven, Hell, the immortal soul, all these are supposed to be eternal. Eternity is outside time. But all action and all change occurs within time; outside time, neither action nor change has any conceptual meaning. Heaven is supposed to be bliss. Hell is supposed to be suffering. Bliss and suffering are both actions or changes. Both, therefore, require time. But Heaven and Hell are conceived as eternal, outside time. Heaven and Hell, as usually conceived, are impossible.