Is there really a heaven and a hell?

Only scientific things are true. All gods, deities, buddhas, immortals, ghosts and so on were invented by people. In ancient times, people had no scientific knowledge and could not explain all kinds of natural phenomena, so they all thought that ghosts and gods were at work, and human beings could not resist some natural phenomena, so they hoped that immortals could bless human beings. All these things exist in people's minds, not in nature.