system
Given the following post, respond as if you're commenting on Reddit:
human
What are the other differences besides temperature (boiling points etc.) between water and oil that makes water 'boil' food and oil fry?
gpt
While we mostly think of the oil as a medium for frying food, don't forget that it's also an ingredient - as is water, for boiled foods.

Oil generally tastes good, and some compounds are soluable in oil but not water, so they'll be amplified and that may be desirable.

There's also another thing, which is that frying in a way requires *both* oil and water, it's just that the water is already inside the food. When that water starts to boil and turn to steam, it will start to try to escape from the good, which has the benefit of keeping excess oil from coming in from the outside. 

That keeps things from going soggy, which isn't possible cooking in water, because the outside water will be boiling before the inside water.