Change necessitates substitution. Here we can appreciate the training in meditation, where we are constantly called upon to substitute our thinking with being attentive to the breath. For one who doesn't meditate the substitution of one thought for another is an unknown factor. To exchange an unwholesome thought with a wholesome thought is an almost unbelievable idea for people who do not know anything about spiritual practice. We are prone to believe what we are thinking. That nobody else is thinking the same has never occurred to us. To be the only one with such a thought amongst four billion inhabitants is an absurdity rarely noticed.