Michael Huemer argues for the following principle:
Phenomenal Conservativism (PC): If it seems to S as if P, then S thereby has at least prima facie justification for believing that P.
So if it seems to me as if my coffee mug is on my desk in front of me, then I thereby am at least prima facie justified in believing that my mug is on my desk. (The phrase 'prima facie' means something like upon first sight or it initially appears as if.) In other words, I can typically trust my perceptions in rendering my beliefs about my environment justified.
So he thinks that it's legitimate to accept things as they appear. As he put it, "... appearances are presumed true, until proven false."
Do you think he's right about this? Should we be phenomenal conservatives and hold that PC is true?