We as human beings offer limited imagination to our progeny. Look no further than kids drawing book. It is full of houses with triangular roofs and rectangular walls. A yellow sun in the sky which is always shinning. And a tree hanging in mid-air. Occasional father, mother, and siblings as stick figures: always smiling.
A few years down the line when these kids learn to observe and imagine better, they realize that no houses around them look the way they imagined them to be. Trees are grounded, their plush branches have their own details. Mother, Father, and Siblings are of different shapes and they seldom smile. There is also a night after a bright day. A celestial body called the moon revolves around the earth.
Now, they lose all hope when they think of replicating all the reality on a two-dimensional sheet. They quit drawing.
This is how idealism paralyzes us. Failure to imagine reality harms us. Theoretical concepts limit us. But we still fall in that trap. And we keep falling.