Look to the sky. See any clouds? What do you think they’re made of? Air, condensation, dust, magic, and unicorns? Chances are you’ve never checked for yourself. You had to rely on the research of someone else. And you’re perfectly fine with that.
But what in the credibility arena did it for you? Was it the authority of the person that did the research? The number of degrees they held or letters behind their name? Or maybe since you didn’t have the time or resources to check, you decided to consider others’ work as the only realistic option?