Remember, meditation is not concentration but neither is meditation contemplation. It is not thinking. Maybe you are thinking about God — even then, it is thinking. If there is ‘about’, there is thinking. You may be thinking about money, you may be thinking about God — it basically makes no difference. Thinking continues, only objects change. So if you are thinking about the world, or about sex, nobody will call it contemplation. If you are thinking about God, virtue, if you are thinking about Jesus, Krishna, Buddha, then people will call it contemplation. But Zen is very strict about it — it is not meditation, it is still thinking. You are still concerned with the other.