When our heart is closed, it is shut to all other hearts. It is the lack of knowledge of ourselves which makes us ignorant of them and closed to us. To say a person "does not open his heart" means that his heart is not open. Were he to understand himself, that understanding would itself help him to understand another. Once he is open himself, the other person no longer seems closed. It is the action and reaction between two hearts. The opening of the one heart has an influence on the other, and it opens. When one's own heart is closed, the other person's heart, though open, will also close.