4609. About mental images
Perhaps some have an inward wish to know what mental images are, and where they come from. To tell it in a few words, they are not anything else but changes and variations in the inward substances that make up the inner person, thus the modifications and variegations there.
[2] When the life of the Lord flows into them, mental images are presented that are called thoughts. Those who do not comprehend that the inner qualities of human beings are real substances, and more real than their outward qualities, cannot conceive any sense of what mental imagery is.
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.
4609. De Ideis
Forte aliqui apud se avent scire quid ideae, et unde, ut paucis dicatur, non sunt aliud quam mutationes et variationes in substantiis interioribus, ex quibus internus homo, ita sunt modificationes et variegationes ibi; in illas cum influit vita Domini, sistuntur ideae, quae cogitationes vocantur: qui non comprehendit, quod interiora hominis sint reales substantiae, et realiores quam exteriora ejus, nullam concipere potest perceptionem de ideis.