The term expert has become synonymous with popularity. The truth is there are many experts whom you’ll never hear about.
The “experts” we should take seriously are the ones who are objective. The ones who think things through and don’t jump to conclusion based on what they want to be true. They accept truth as it is, whether they like it or not.
Even the experts don’t always know what they’re talking about. Don’t simply take the expert’s word for it, and don’t be guided by emotional appeals. Also pay attention to whether they’re telling the whole story, or being selective.
Treat it like a police investigation: weigh all the evidence and decide whether there’s enough to believe beyond a reasonable doubt that what that person has said is true. Re-open your case if new evidence comes to light.