Imagine there was a gorge, which is a river cutting through a deep valley, and there were two villages on both sides of the bank. Humans are interactive beings so they built a straight wooden beam bridge to link the two banks together. Ever since, they started trading and making friends with the other side of the bank.
However, when the rainy season came, the river would gain velocity and erode the bottom of the banks away, causing the edges of the bands to crumble. The bridge crumbled into the river as well.
Every year after the rainy season, the villagers would build a longer beam bridge to link the banks, which were parting annually. It became a culture and their way of life.
Until a year came when a straight beam bridge is unable to be constructed because the bridge could not withstand its own weight and it snaps from the centre. Humans, being highly intellectual beings, explored the solutions and constructed an arch bridge instead, where the weight of the bridge falls evenly at either side of the bank.
Years passed until arch bridges were inadequate solutions. As the bridge gets bulky, the curvature of the body of bridge had to be increased. It had come to the point where arch bridges were ineffective for the villagers to pass through.
Humans exercised their powerful imaginative ability and constructed a suspension bridge.
One year, a smart person came up with the idea to build sturdy artificial riverbanks. As such, the erosion of river can be ceased and bridge constructions could be abandoned. The idea seemed plausible and people started the strenuous construction. Although it took months, the villagers were overjoyed when it was accomplished. Every rainy season since then, crumbling of the bridge did not trouble the villagers. The skills of bridge construction were slowly forgotten.
Decades passed when the artificial riverbanks finally gave way. The bridge collapsed. The villagers had forgotten how to get to the other side. They were separated, forever.
Knowledge is power. It may not be necessary at times, but it is always essential. Just like mathematics.