Final answer:
Han Feizi, a key figure in the development of Legalism, believed humans are inherently self-interested and moral codes are only followed if self-benefitting, thus the state must enforce order through a strict legal system with harsh punishments.
Step-by-step explanation:
The belief about humans that influenced Han Feizi in the development of Legalism was that humans must be forced to act right. Legalism, as a political philosophy, posited that humans are inherently self-interested and would only follow moral codes that benefit themselves. Therefore, according to Legalists like Han Feizi, the state must enforce a clear legal code with harsh punishments to ensure societal order and compliance. This view contrasts with Confucian ideals which emphasize the importance of moral cultivation and virtue.