My friend Jina shared this quote with me:

‎"When people ask me: 'Norm, how do you feel about stem cell research?' I say: 'Why don't I just go to the University of Science for 10 years and then come back to this very spot and tell you what those three words mean. Because I don't know.'" - Norm MacDonald

Norm points out a very common human weakness: that we tend to assume we know more than we actually do. Our brains are funny things; we're possess an awareness of our beliefs and the world around us, but we tend to lack a meta-awareness, or, put another way, an awareness of our awareness.

Take the ongoing and tedious debate about evolution versus creationism: the debate itself is a social construct. It could not possibly occur in a civilization of one or two people. There's no single piece of evidence that points to evolution; lots of scientists and small bits of evidence can be constructed to make an arrow that points in that direction. People who aren't evolutionary biologists (and probably some who are) ultimately have to decide they trust the efforts of these scientists enough to believe this conclusion. For a creationist, the problem is the same: none of us have any direct experience with the origins of the universe, but there's a very authoritative 2,000-year-old book that describes its conception, and we ultimately have to decide if they have enough faith in this book to believe this conclusion.

Our opinions on this topic (and lots of other complicated ones) are not based on our own experience, but on the collective observations, conjectures, speculation, and theories of other many other people. You probably know that atoms are constructed of clumps of protons and neutrons with electrons in orbit around them. But: ever see this for yourself?

Looking at it this way, the question shifts from "Who's right?" to "Who am I choosing to believe, and why?"