For instance, a person was told that he must go and see his friend on such a day at a certain time. He had written it in his notebook, but then he forgot it. During his daily occupations there came a moment when he thought, "I ought to be in that place! I have not gone there. I had quite forgotten. I should have been there. Why am I not there? Why did I forget it?" Now this idea that came to his memory was in his subconscious mind. And as his will wanted to know it came up; he knew without doubt that he had an engagement, that he was meant to be there. Only for the time being he had forgotten. Where was it? In that part of his mind which one calls the subconscious.