That may be the same sort of usage of the simple present tense as a sports announcer uses at a live sporting event:
“He aims… He shoots… He scores!”
Or the person could be looking at the topic as a commonly heard story or a standard procedure – which of course would always be the same and wouldn’t change. Therefore the person feels very certain:
“I have a feeling (that I know for sure) what happens next (in the story/in this procedure).”
It would not be wrong to use is going to happen oris supposed to happen or might happen etc. in the sentence above. It all depends on context and the speaker’s point of view.
Regarding your additional examples:
One very large difference is that your further examples are all negative (i.e. they refer to not knowing and/or uncertainty). And they seem to refer to specific/unique future events rather than “standard” future events.
Your two sentences: know what will happen/happens next have a slightly different meaning in sense rather than in grammar.
Let me explain. If for example you have already seen a play, you could say to someone with you who hasn’t seen the play: I know what happens next - in other words I know the sequence of events.
Another situation: One of your friends who is very bad at managing money and often asks you to help him/her has got to pay a large sum of money on a repair and hasn’t got any money to pay for it. You could say: I know what will happen next, he’ll ask me to lend him/her some money - in other words that is inevitable and that is your prediction based on previous experience.
Yes, Tamara. But I think you missed a very important point in what I wrote before:
If someone sees something as a “standard” future event (similar to the “standard” arrival of the 10:20 train at 10:20 – or if the 10:20 train is absolutely always 15 minutes late, then it would be the standard arrival of the 10;20 train at 10:35… :lol:) then they might choose to use the simple present tense to talk about the future because what is expected to happen in the future is what alwaysstandardly happens. Just as things always work or happen the same way in a procedure every time the procedure is used (ie. yesterday, today and tomorrow: always the same). These are NOT seen as unique or unusual in any way. The future event would be just one of many of exactly the same thing.
I know the story of Romeo and Juliette. I can listen to/read the story again and again and say: “I know what happens next.” Why? Because it never changes. It’s always the same.