Final answer:
John Stuart Mill introduced the concept of qualitative distinctions in pleasure, identifying higher and lower pleasures. He stated that any qualitative difference in pleasure should result in a difference in the quantity of pleasure.
Step-by-step explanation:
John Stuart Mill, a philosopher who developed the concept of utilitarianism, introduced the idea of qualitative distinctions in pleasure. He believed that pleasures could differ both in quantity and in quality. Mill identified higher and lower pleasures, with higher pleasures being associated with the use of higher cognitive faculties and participation in social/cultural life, while lower pleasures are more basic sensory pleasures. Ultimately, Mill argued that any qualitative difference in pleasure should result in a difference in the quantity of pleasure.