Human desires inherently possess no notions of good or evil, but they must be measured, must be gauged, must be regulated.
Indulgence in basic desires often leads to dire consequences.
Take hunger, for example.
Hunger instinctively drives people to eat. Some choose to rob others of their food, others choose to deceive to reap the benefits, while some choose to toil for themselves.
Hunger is not inherently evil, but plundering is. Cultivation through plowing and burning, however, is a noble and righteous way arising from hunger.
Humans are born with both divine and demonic natures. They instinctively yearn for beauty and also inherently possess the urge to destroy.
A single thought can sway between good and evil, divine and demonic out of place.
Therefore, a cage is needed to imprison the basic desires, to prevent them from breaking norms.
Taming basic desires is the process of cultivating the mind.
