First in order after Tao is Tʽien (天), or the material heaven above us. This is represented as pure and clear in consequence of having obtained the One—that is, in consequence of having participated in the great “over-soul” or Universal Nature.[20] Were heaven to lose its purity and clearness it would be in danger of destruction. Of the heavenly bodies and their revolutions, Lao-tzŭ does not make mention, nor have we any means of ascertaining what were his ideas respecting them. Nearly all that he says about Tʽien or heaven is metaphorical, with apparent reference to an agent endowed with consciousness (according to our ways of thinking). Thus he speaks of it as enduring for a long period because it does not exist for itself; as being free from partiality towards any of the creatures in the world; as being next in dignity above a king and below Tao, and as taking this last for its rule of conduct.[21] The space between heaven and earth is represented as like a bottomless bag or tube,[22] though this is perhaps merely a metaphorical expression. The earth itself is at rest,[23] this being the specific nature which it has as the result of its participation in Tao. The heavens are always revolving over the earth, producing the varieties of the seasons, vivifying, nourishing, and killing all things; but it remains stationary in calm repose. Were it to lose the informing nature which makes it so, the earth would probably be set in motion. Its place is next in order after heaven which it takes as its model. It is impartial, spontaneous, unostentatious, and exists long because it does not exist for itself. Neither in heaven nor on earth can anything violent endure for a lengthened period. The whirlwind and heavy rains may come, but they do not last even for a day.[24]