Theoretical thinking is just a thought without experience or actual study of the fact. This kind of thought imagines that matters proceed very naturally, without obstacles on the way, following certain rules that this thinker put in his mind.
It is exactly like a person who says that the distance between two countries by sea is so many miles. If the ship sailed at a specific speed, it should arrive on such a day, at such an hour… The ship then gets into the actual fact, where it could be hit by waves or wind and fail to move, resist with difficulty or change its direction. It might arrive after days, or it might never arrive!!
The actual fact is full of obstacles and hindrances that nobody knows, except the one who has experienced the practical life in its minute details.