It was natural and healthy that universities were "always in a state of evolution", the Timaru novelist and short-story writer told graduates at a University of Otago graduation ceremony in Dunedin on Saturday.
But Mr Marshall warned if the university as a whole "ever loses that essential love of knowledge for its own sake, that scholastic enthusiasm and tolerance, then the spark will be gone".
The university was then likely to be "a place of formal, empty pedantry, meal-ticket mentality, or a debased, bums-on-seats democracy", he told about 310 graduates, mainly in education, teaching and pharmacy, at the Regent Theatre.
Though not an Otago graduate, he had links with the university, especially through his "good fortune" of holding Otago's Robert Burns Fellowship in 1992.
"Everyone seems to be an expert on education, and a good deal of vehement and often ignorant criticism is advanced, for always there are people who are eager to find fault in the performance of others, yet unwilling or incapable of taking responsibility themselves.
"Of course we need accountability, efficiency and a response to modern youth and modern society.
"We also need to preserve and commend those values that are at the heart of the best universities - scrupulous scholarship, academic enthusiasm, intellectual curiosity, a fellowship of the heart and mind, and a desire to pass on knowledge."
He emphasised the need for gratitude, which was "not much in fashion these days".
"We hear much of rights, accountability, consumers, performance and delivery, all in a mechanistic way, but not much about gratitude, and not much about dedication."
Graduates owed gratitude not only to family and friends but also to Otago University itself.
And he thanked Otago staff who had "persevered through the squalls of restructuring and the doldrums of educational policy, to maintain a vision of senior study that upholds opportunity based on talent, an openness to intellectual possibility, the value of reason and knowledge of life generally."
During difficult times for tertiary institutions, finance was "a constant concern".
People were the "heart of a successful institution" - people who were "fascinated by their subjects, whether it be teaching practice, educational theory, or the alleviation of illness through pharmaceuticals."
"We make play with the stereotype of the absent-minded professor, but it reflects the concentration and dedication of the true academic," Mr Marshall said.