Richard Feynman defined science as "the belief in the ignorance of experts." Science begins by questioning established ideas. ...Even those ideas promoted by so-called experts.
The value of science that's obvious to everybody is the chance you might discover some valuable truth that nobody else has discovered before. That's the glamorous idea that might motivate you to begin the hard work that science sometimes requires. Science is also valuable to you when you learn that an established idea, no matter how much you may not like it, really is true after all. That second value of science is not as glamorous, but it's just as important. My little prayer with respect to that possibility is, "If an idea I believe is wrong, please let me find out before anybody else does."
Everyone can do science. Not just "scientists"; all of us. But you need to do science "right," or it's not science. Do it right, and you accumulate a little bit of truth. Do it wrong, and and you've wasted your time, or worse, you've doomed yourself to waste more of your time in the future, too.
The difference between "right" and "wrong" in science is not some snooty, bureaucratic concept. You don't need a license or a blessing to do science right. You just need to ensure that the cause-effect relationships you choose to believe are actually correct. One of the rules for doing science right is that you measure instead of just asserting your opinion.
Different people have different thresholds of skepticism. Some people believe new ideas, whether they're true or false, with very little persuasion. The people who are persuaded easily to believe false things cannot contribute much useful new knowledge to their communities (irrespective of how much they might publish).