John's father, Peter, was a wealthy planter who owned slaves. John grew up in a slave-owning society and initially accepted the institution of slavery as normal. However, as he grew older, he began to question the morality of slavery. He was troubled by the fact that slaves were treated as property, rather than as human beings, and he was aware of the brutality and violence that was often inflicted on slaves.
In the early 1770s, John began to speak out against slavery. He wrote a series of essays in which he argued that slavery was morally wrong and that it should be abolished. In his most famous essay, "African Slavery in America," he wrote:
>"The slaves in America are not only deprived of their liberty, but they are also treated with the most shocking cruelty and barbarity...They are beaten, whipped, and tortured, without the least provocation, and for the most trifling offenses. They are sometimes even put to death in the most cruel and inhuman manner."
John also argued that slavery was harmful to the economy. He believed that slavery prevented the development of a free and prosperous society, and that it led to social inequality and conflict. He wrote:
> "Slavery is not only an evil in itself, but it is also a source of great expense and inconvenience to the country. It prevents the growth of population, and the improvement of the soil. It discourages industry, and produces idleness and luxury."
John's views on slavery were radical for his time. He was one of the first white people in America to speak out against slavery, and he faced considerable opposition from slave owners and other supporters of slavery. However, he never wavered in his belief that slavery was wrong, and he continued to fight for its abolition until his death.
In 1777, John helped to found the Pennsylvania Abolition Society, one of the first organizations in the United States dedicated to the abolition of slavery. He also served as the president of the Society from 1787 to 1791. John's work for abolition helped to inspire the abolitionist movement in the United States, and it ultimately led to the abolition of slavery in 1865.