But are we expecting answers to a question towards which anyone can make up his own answer and no-one can 'prove' it as being wrong or right ?
Well, one can discover that certain systems are less unwise. For example, faith, while undoubtedly useful, is not the best tool for finding things out about the universe or exploring ideas and concepts - science and philosophy do a better job.
Isn't that because in order for induction/deduction to work, one must make a few basic assumptions like those?
For deduction, certainly. Maybe not for induction, because you're working from the other direction - from the results towards the underlying reason. Like, "things fall down, therefore gravity," not "gravity, therefore things fall down." Though in practice one would have to assume that the world is constant, in order for induction to have any use.