In the classical version of utilitarianism theory, J.S. Mill…

In the classical version of utilitarianism theory, J.S. Mill was the philosopher that focused on the quantity of the pleasure (i.e., simply how many units of pleasure/happiness), and J. Bentham was the philosopher who also took into account the quality (type) of the pleasure produced (i.e. intellectual pleasures versus simpler ones) when assigning the number of units of pleasure from each activity.