Plato may have been a genius, but he was also pretentious. Take his Allegory of the Cave for instance. If you're not familiar with it, check it out - Book VII from Plato's Republic. This text has become a model for the way people understand knowledge and Truth. But there is a problem with the model.
Plato assumes that only select people are able to withstand turning to face the light head on. If most people in the cave saw the light of Truth, they would be blinded by it at best. I can't agree. I don't believe that only a few people can really know Truth.
However, that doesn't mean I believe everyone can look into it either. Quite the opposite- I believe no one can look on Truth without being blinded, consumed by the light. This is where a pair of sunglasses comes in handy.
Grace is like a pair of sunglasses. It allows us to see Truth we would never be able to bear witness to on our own. Looking on Truth, God ("I am the Way, the Truth, and the Life", John 14:6), would indeed blind any who turn to look. But with grace on, we can not only look on Truth, but come to know Him and enter His realm of consuming light where we become more whole than ever before.