There is a nice theory developed into this book:
https://www.goodreads.com/book/show/25980203-the-road-of-time from a french physicist named P. Guillemant.
His idea is that all the potential paths that we have are pre determined from our birth but we have the ability to choose which ones we want to experience.
Its like a tree of paths. If you come to a fork and choose left, then, your next options will be different than if you had chosen right... and so on. So, depending on our free will / decisions, we enable or disable our future experiences or we make some experiences more likely or less likely to happen.
I believe that psychics are able to sense / see what are the most probable paths available in our future or in the future of the people we inquiry about. Now, people can always take the paths that are offering fewer opportunities or are less probable. In that sense, psychics are like a compass or a headlight, they give us some heads-up on what lies before us... but things are not set in stone, and some decisions from us or others can change the probabilities for our future opportunities.
Hope it makes sense