When experts study animal behavior, they identify many key “motives” that likely drive such behavior, even if those animals aren’t consciously aware of them. Such as getting food, avoiding predation, and making and raising babies. Most such motives also apply to humans, as do several new human-specific motives. Biologists and social scientists have had great success over centuries explaining animal and human behavior using these motives. And ordinary people also commonly and successfully use such motives to explain the behaviors of distant humans and animals.
We humans also use a standard related set of motives to explain and choose our future behaviors, and to persuade associates to choose behaviors. Such as when we are trying to decide between careers, schools, romantic partners, hobbies, etc. For example, one might suggest that an associate try a particular hobby based on its financial or time costs, health benefits, satisfaction from a sense of mastery, the variety and novelty it lets you experience, prestige conferred, connections to valued communities, or chances to see nature, meet people, or gain recognition. Most people are comfortable with roughly predicting who might adopt, or drop, which hobbies based on such considerations. E.g., an invalid is less likely to pick a physically demanding sport.
But for many big decisions, our tune tends to change once we have repeated such a choice for long enough for it to become a habit. At that point, we tend more to say that we do such things because they are “fun” or “enjoyable” or “for their own sake”. And we are reluctant to explain such enjoyment in terms of the other usual factors that we use to explain human behavior from a distance. Oh, we might admit that such factors would make us more likely to make the choose we did, all else equal. But we are reluctant to grant that enough such factors could add up to most of an explanation. We instead insist, “The main explanation for my choice is just that I like it.”
For example, consider someone who “likes to drive”. The explanation that they do this “for its own sake” will not help us much to predict how fast, how attentive, in which kinds of cars, on which roads, or at which times of day or climates. Or how often they choose to drive alone or be a passenger, or how much a driving video game might substitute. But these sorts of details can usually be explained via other factors such as their wanting distraction, liking control and mastery, liking wind in their hair, wanting to be alone, liking to see new things, or liking to feel the car’s vibrations. While a driver might admit that these factors do help to explain such details, they still may insist that these aren’t the main reasons they drive, they just drive “for its own sake”.
And yet surely humans didn’t evolve a special mental module that promotes driving cars. So if humans do like to drive on average, that must be via support from mental modules adapted to ancestral human environments. (Including modules that say to keep doing whatever you have been doing.) So a good explanation of our inclinations to drive would list typical supporting modules, and why they tend to be triggered to support driving in modern environments. Which seems pretty close to a list of factors that explain why we like driving, and quite different from “driving for its own sake”.
Now it does makes sense that when we look inside ourselves, our mind parts might tell us “we are pretty sure of this choice, so you don’t need to reconsider it”. But we are pretty sure of many other choices where we are also able to reason abstractly about what drives those choices and what might make us change them. For example, we are usually pretty sure we don’t want to stay underwater long, but we admit we’ll reconsider if scuba gear is offered. So something different is going on with “for its own sake”.
Note that in related areas, we often criticize people who are too aware of certain influences on their choices. For example, people who pursue some kinds of art because it will make them popular or respected are often called “inauthentic posers”.
Note also that while we often try to explain our relationship choices in this way, e.g., “I just like you”, our partners often push us to identify factors to explain our choice, e.g., “you are smart” or “you are pretty”. Except that our partners usualy do not want us to embrace the implication that we’d swap them for someone who ranked higher on such considerations. Here it seems there is no way to win except to just squirm, and maybe this is mainly just a test of how much you are willing to squirm for them.
Your mind lies to you, and lies to you about whether it lies. Which makes it hard for you to see such lies. So I offer this clear example. See those habits of yours where you feel like you just do them “for their own sake”? That is just where your mind doesn’t want you to think about the factors that cause you to adopt or not drop such habits. It makes you quickly look away, just as you do when you glance at the sun.
I think there's an important distinction to be made between not knowing one's motives and being motivated by something wholistic that cannot be reductionalistically described in terms of other motives, even if it is related to those other motives.
There’s a difference between someone's intelligence and looks influencing how much you like them and liking them only or primarily because they're smart and pretty. Sometimes people will like somone for the latter reason and just hide that from themselves, and I agree that this is distasteful.
But I think often liking something for its own sake is just that, even if the own-sake-ness is influenced by other factors. After all, given that intelligence and looks are part of who someone is, it's totally consistent to like someone "for who they are" and for that decision to be influenced by their being smart and pretty.
I think what people primarily object to is the way of thinking in which things are a means to an end, and in which the value of something can be separated into distinct factors. That sort of thinking is super valuable in some contexts, but never captures the whole picture.
(The Master and His Emissary by Iain McGilchrist is one good book that discusses these two ways of thinking.)
I can think of no habits that I like "for their own sake."
Do people really think this way?