Satan's World,
V.
In the Serendipity castle on the Moon, Kim wants to get Falkayn out of a room with a view so that he won't see a spaceship take off. Sensing that Kim wants him out although not yet knowing why, Falkayn stalls, says that he wants to remain in the room alone to meditate and meanwhile runs off at the mouth about Buddhism, saying that:
purer Buddhist sects might not count as religions because they are agnostic about gods and other "'...animistic elements...'" (p. 374);
karma need not imply reincarnation;
nirvana is not annihilation but can be achieved in this life...
Before he can say what nirvana is, the spaceship takes off.
I suppose that, by purer sects, Falkayn means basic forms of Theravada. I understand that Buddhism has always been practiced within local worldviews. Buddhist texts refer to Indra. In Japan, there are Buddhas and Shinto gods. But the deities are not necessary for meditation. However, Buddhism is a religion because it is an approach to spiritual emancipation and transcendence.
Having analyzed mental processes, the Buddha concluded that there are no souls, therefore no reincarnation, but still referred to rebirth of karmic consequences. I think that rebirth is an unnecessary hangover from reincarnation. Karma is right or wrong action with good or bad consequences, respectively. We experience karma within a single life.
Buddhism can be presented very negatively, thus:
the only way to end suffering is to end consciousness;
the only way to end consciousness is not by suicide but by meditation which prevents rebirth;
thus, effectively, monasticism is elaborate suicide and an optimal world would be one with neither sex nor birth/rebirth ever occurring in it!
In fact, Buddhists experience joy here and now. The fact that Jiddu Krisnamurti, who rejected all supernaturalism, said that, if the Buddha were here, he would follow him to the end shows that the essence of Buddhism is not the teaching about ending rebirth or any other set of ideas.