1. Humans can see only those beings in the human and animal realms.
2. Devas (in the six Deva realms) and Brahmas (those in the 16 “rupa loka” realms) can visit the “human world” and see the humans. During the time of the Buddha, many Devas and Brahmas visited to listen to the Buddha. But there is no incentive for them to visit, but it is possible.
- We cannot see them even if they visit because they have delicate, subtle bodies. They can make themselves seen by humans.
