[renewiltord]

I think this view is best established in The Remains of the Day by Kazuo Ishiguro. It's a fairly traditional view but well described there.

For what it's worth, I think it depends on the shape of the thing. "What actually" is not a fixed concept like that. For instance, "what makes a good vacation?". One could say "not having faeces on your nose for the whole time" since, after all, it is unlikely that having faeces on your nose the whole time is likely to make a good vacation even if you're on the most lovely beach surrounded by all you live. But that's a baseline that's easy to meet. So what _actually_ makes a good vacation? The truth is: ∄ an activity or characteristic X such that ∀ vacations V that have X, V is a good vacation.

So what "actually makes people happy"? No one knows. We know things that can make you unhappy (faeces on the nose, not having any relationships) and we know that there exists a baseline happiness we have (the Hedonic Treadmill, etc.). But really, not much more.