Full Idea
The masses…seem - not unreasonably - to believe that the Good or happiness is pleasure.
Gist of Idea
The masses believe, not unreasonably, that the good is pleasure
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1095b15)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.68
A Reaction
Since Aristotle seems to see the pursuit of understanding, through various types of philosophy, as the supreme good, then this is 'understandable' because the masses lack the education for such a thing.