Before modern period, Philosophy and Science were chiefly concerned with speculation about the ultimate questions of reality and human existence. But once the focus shifted towards the practical side, endeavors of philosophers and scientists became extremely fruitful. This shift is what gave rise to the modern science. Similarly in the matter of Free-will and Predetermination the focus should be on the practical side and it is a mistake to involve in too much speculation on this subject.
Practically we make decisions about free-will and predetermination on daily basis in our lives. Regarding the actions of other humans, we judge all the time whether they were made with freewill or not. We do it in our courts, we do it at our home with kids. Most of the time we do it with such an ease that we don’t even think of problem of freewill as a problem in practical terms.
Now to understand the philosophical questions related to the problem of freewill, Islamic position is to avoid getting involved in these speculations. These issues are beyond our comprehension till we are in this world, we have to wait till next life.