4609. CONCERNING IDEAS. Possibly, some wish in themselves to know what and whence ideas are. To tell it in few words, they are nothing else than the changes and variations in the interior substances of which the internal man [is composed]; thus they are modifications and variegations there [i. e., in the interior substances]. When the Lord's life inflows into them, there are presented ideas, which are called thoughts. He who does not comprehend that the interiors of man are real substances, and more real than his exteriors, cannot take in any perception of ideas.