We know things based on a variety of circumstances. We know our
friends from our accumulated interactions with them. We know
language largely from listening to others speak. Much of what we
know is similarly built on our personal experience. Some of what
we know is gained by learning from those whose insight and
wisdom we trust – whether it be a minister, a political leader
or a teacher. We all rely on others for some of our knowledge
and our beliefs. In some cases, there is a widely agreed upon
reality, such as how an internal-combustion engine propels a car
down the road. Most of us don’t have direct experience with the
thousands of small explosions in the piston chambers, yet we
accept that it is from the energy released in these explosions
that moves the car. Similarly, we have vague understandings of
how computers, light bulbs and other mechanical items work. For
other things, such as why a thrown ball will return to the
ground, how the Earth rotates around the sun and the moon around
the Earth, most of