We've learned that not all questions we can ask have answers we can find. Any question which is in principle or in practice untestable, is not considered a valid scientific question. We like to think we don't waste time on those, but they seem to pop up in internet and classroom discussions quite often. Many people think unanswerable questions are the most profound and important ones. Scientists should set these aside for the philosophers to chew on, and get on with the business of answering more accessible questions.
Science progresses through trial and error, mostly error.
Every new theory or law must be skeptically and rigorously tested before acceptance. Most fail, and are swept under the rug, even before publication. Others, like the luminiferous ether, flourish for a while, then their inadequacies accumulate till they are intolerable, and they are quietly abandoned when something better comes along. Such mistakes will be found out. There's always someone who will delight in exposing them.