"...once the cards are dealt we turn them up in turn, and make two piles each, one red, one black; the winner has the biggest pile of red ones. So once the cards are dealt the game is determined, and from any position in it you can derive all others back to the deal and forward to win or draw. ...in relation to the solar system..., the laws are like the rules of an infantile card game.... But in relation to what happens on and inside a planet the laws are, rather, like the rules of chess; the play is seldom determined, though nobody breaks the rules."