As Plato asked, “Are these things good for any other reason except that they end in pleasure, and get rid of and avert pain? Are you looking to any other standard but pleasure and pain when you call them good?” Indeed, feelings don’t just matter—they are what mattering means. We would expect any creature that feels pain when burned and pleasure when fed to call burning and eating bad and good, respectively, just as we would expect an asbestos creature with no digestive tract to find such designations arbitrary. Moral philosophers have tried for centuries to find some other way to define good and bad, but none has ever convinced the rest (or me). We cannot say that something is good unless we can say what it is good for, and if we examine all the many objects and experiences that our species calls good and ask what they are good for, the answer is clear: By and large, they are good for making us feel happy.
Stumbling on Happiness
Daniel Gilbert