I have heard the following story:
Three blind men are sitting around a table in a house where they were
guests. They are discussing whether the fruit the host offered to them was
grape, pear or peach. None of them has ever eaten or touched any of the three kinds of fruit. They have, however, read a lot about different fruit, and
from that they knew what experience other people had about them. Each of them
had a definite opinion about the issue. One of them said the fruit was grape,
the other insisted that it was pear, whereas the third one argued that it had
to be peach, and each of them believed that he and only he could be right. The fourth person present, the host who was not
blind, said that none of them was right; the fruit they tasted was apple.