If people have no concept of heaven and do not want any concept of it other than one of some insubstantial atmosphere in which angels fly around like intellectual minds without the senses of hearing and sight, they cannot believe that angels have language and writing. They locate the entire presence of everything in matter. Yet the things that one finds in heaven occur with just as much reality as those in our world, and the angels who are there have everything they need for life, and everything they need for wisdom.
from Heaven and Hell, Sections 264
Secrets of Heaven 