[danbruc]

In case of the river puzzle there is a huge difference between repeating an answer that you read somewhere and figuring it out on your own, one requires reasoning the other does not. If you swap out the animals involved, then you need some reasoning to recognize the identical structure of the puzzles and map between the two sets of animals. But you are still very far from the amount of reasoning required to solve the puzzle without already knowing the answer.

You can do it brute force, that requires again more reasoning than mapping between structurally identical puzzles. And finally you can solve it systematically, that requires the largest amount of reasoning. And in all those cases there is a crucial difference between blindly repeating the steps of a solution that you have seen before and coming up with that solution on your own even if you can not tell the two cases apart by looking at the output which would be identical.