A young skeptic once called into Greg Koukl’s radio show, Stand to Reason, and asked why we should believe our senses are reliable.  Why shouldn’t we believe we are in some computer program like the Matrix, which has fooled us into believing we are experiencing reality when in fact we are not?

Greg’s answer was ingenious: because we’re alive!  Survival in the real world depends on our ability to accurately perceive the real world and maneuver safely within it.  If our perception was off even a little, the effects would be disastrous.  That’s why people who drive cars while intoxicated often end up in fatal accidents: their ability to accurately perceive the outside world is impaired.  The fact that we are still alive demonstrates that our senses allow us to perceive reality in a fairly accurate manner.

But couldn’t it be the case that the outside world we think our senses are accurately perceiving isn’t really the outside world at all (like the Matrix)?  Yes it’s possible, but why should I believe that to be the case?  Just because it’s possible that we could be mistaken in what we perceive about reality does not mean we are mistaken, or should think we might be mistaken.  Possibility and probability are not the same things.  We are prima facie justified in trusting our senses that what we perceive to be the real world is the real world, until evidence arises to the contrary that would falsify this properly basic belief.

See J.P. Moreland’s short article entitled “Answering the Skeptic” for further reading.