This would be a good example, if it applied better to the game. It doesn’t. If we were talking about a reality-simulating game, we would be talking about GURPS. We’re not. And in this particular game, the examples made by SamWilby apply. Which means that Learning and Logic can accomplish same things, but with different time investment/roll requirements.
Also, your example conflates a mechanic’s skill with Logic, when in reality it’s also Learning. Both professor and mechanic are learned individuals, but they’ve studies different fields. One is also self-taught, when the other is shcool-taught. They both, however, are learned individuals.
I think combining Logic and Learning into one attribute would also be prudent from the game design perspective. Making redundant entities clutters up the system. Note how other attributes are not raising this kind of discussion. Agility is not being confused with Might, Perception is not being replaced by Will. And yet Logic and Learning are mutually replaceable and very much alike, confusingly so, despite the fact that they can, sometimes, be different. They are not different enough to justify having them both. It’s like having “Spot” and “Search” checks in 3,5 D&D. They are different, but not different enough, and thank god they have been combined into one in later editions.