There is a high pile of bricks on the ground. In which case is it necessary to apply a large horizontal force: to pull out the fourth brick from the top while holding the rest, or to move the five top bricks while also holding the rest?
A lot of force must be applied to pull out the fourth brick, since the Fenian forces from the third and fifth bricks will act on it.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.