Three men and a dragon

Three men were walking along a road when they ran into a dragon.

The first one said to the dragon, "You cannot be a dragon! Dragons are creatures of fairy tales; they do not exist in the real world."

The dragon ate the man.

The second one said, "A dragon you may be, but you still do not exist. You are nothing more than a thought-perception that has entered my mind, for all of life is an illusion."

The dragon ate the man.

The third one ran off at the first sight of the dragon and hid.

The dragon could not find him, and so he lived.

The first man was intelligent. The second man was wise.

But the third man was smart.