Complex sentence: Van Evrie's views on slavery rested on his belief that black people, though human, differed fundamentally from white people; though he saw black people as unsuited to social or political equality, he felt that under competent guardianship they could be socially useful.
Split into simpler sentences: Van Evrie's views on slavery rested on his belief that black people though human, differed fundamentally from white people. Though he saw black people as unsuited to social or political equality, he felt that under competent guardianship they could be socially useful.