Generally speaking, scientists don't believe in ghost or god. Some scientists may, but almost all the scientists can't prove the existence of ghost and god. And so can we say that there's no ghost and no god in the world?
Certainly not. But be careful that we cannot say either that there's ghost and god for sure. All right, is there ghost, or something like that in the world anyway?
The problem is not whether there's actually ghost or not, neither whether modern science and technology can prove it or not, but rather that once we have admitted its existence, we could explain and solve every problem in the world.
For example, you get sick and you might think that evil causes it. You should drive out this evil first. This could be a right decision more than 100 years ago and it's OK if not so serious, but if our problem were so serious that we could not dismiss like the big earthquake or other natural disasters, we would need to seek another reason that it happens and another solution. And thus our ancestors need a scientific way of thinking and solution to know what the world and nature works and to solve the problem.
To live in modern society is, in a way, to do away with any superstition lying behind everything in the world. To accept the way of science, we can live happier in a better place. We can never deny any ghost and god, but if we accept ghost and god, we all go back to the past and do away with our modern life.