536. As in the foregoing pages much has been said about the perception possessed by the churches that existed before the flood, and as at this day perception is a thing utterly unknown, so much so that some may imagine it to be a kind of continuous revelation, or to be something implanted in men; others that it is merely imaginary, and others other things; and as perception is the very Celestial itself given by the Lord to those who are in the faith of love, and as there is perception in the universal heaven of endless variety: therefore in order that there may be among men some conception of what perception is, of the Lord's Divine mercy I may in the following pages describe the principal kinds of perception that exist in the Heavens.