If you know physics perfectly, and know all the starting conditions exactly, you can then predict the movements and positions of a dice you throw at every moment.

I think the same applies for the world we live in, it's all already determined, but we can't know what will happen because we don't know all the conditions and data needed for this nor we have a model to calculate it, but it's theoretically true, just irrelevant since we can't do much with it.