In his early days, Hong was educated by Kim One-hang of Seock-sil Seowon.
Hong was an early leader of the Profitable Usage and Benefiting the People (Hangul: 이용후생파. Hanja: 利用厚生派; ready reckoner: Iyong Husaeng-pa) school of thought. lieutenant worked to promote the industrialization of his country and the development of trade by positively introducing Western technologies to Joseon of Korea.
In China, Hong witnessed a brilliant development of Qing Dynasty and experienced culture shock.
After returning to Joseon, Hong insisted enhancing the national prosperity. Hong was also interested in astronomy and mathematics.
He maintained the rotundity of the Earth and Earth"s rotation. Traditional Confucianists regard that the sky is globular and the ground is square so they couldn"t understand Hong"s idea.
Also, He firmly excluded the Anthropocentrism.
Hong thought all things in nature are equal. After being failed Imperial examination (a kind of examination for the high civil service) a few times, Hong gave up examination and was absorbed in astronomy research. He wrote Catechism of Eusan mountain(Hangul: 의산문답.
Hanja: 醫山問答), which contains the concepts of Earth"s rotation and the equality among species and the infinity of outer space.
In mathematics, Hong worte Interpretation and Usage of Mathematics(Hangul: 주해수용. Hanja: 籌解需用). And he worte Travel Essay of Yanjing in 1765 and 1766(Hangul: 을병연행록.
Hanja: 乙丙燕行錄), a travel journal about his China traveling In 1774, Hong was recommended for a mentor of, who afterwards would be King Jeongjo.
Hong discussed many topics and themes with crown prince.
Crown prince demanded Hong to go into government service and be his own staff members, but Hong indicated his refusal in a roundabout way. Hong wrote Journal as the Mentor of (Hangul: 계방일기. Hanja: 桂坊日記), which contains their debate contents.
After crown prince ascended the throne following the passing of the King Yeongjo, Hong was appointed to local county governor.
In there he tried to test his progressive ideas in local society. However, his mother"s health condition deteriorated in 1782, so Hong abandoned a service and came back to Seoul.
In 1783, mother regained her health, but Hong had a sudden stroke. He wouldn"t make it by morning, and breathed his last breath the next day.
lieutenant was 23 October 1783(Lunisolar calendar) as 17 November 1783(Solar calendar).
Although was satisfied with Hong"s studies and polymathy, Hong found their difference of views among several topics and the conservatism of Prince.