A colonnaded circular monument to the right was raised in the memory of Dugald Stewart, professor of moral philosophy at the University of Edinburgh in the 1780s.
Dugald Stewart had a monument because he taught moral philosophy well.  
mnli hypothesis: Dugald Stewart had a monument because he taught moral philosophy well.   premise: A colonnaded circular monument to the right was raised in the memory of Dugald Stewart, professor of moral philosophy at the University of Edinburgh in the 1780s.