A Story: Thinking that you know what is good or bad

Taken from Tao Te Ching by Stephen Mitchell.

The Huai Nan Tzu tells a story about this:

A poor farmer's horse ran off into the country of the barbarians. All his neighbors offered their condolences, but his father said, "How do you know that this isn't good fortune?"

After a few months, the horse returned with a barbarian horse of excellent stock. All his neighbors offered their congratulations, but his father said, "How do you know that this isn't a disaster?"

The two horses bred, and the family became rich in fine horses. The farmer's son spend much of his time riding them; one day he fell off and broke his hipbone. All his neighbors offered their condolences, but his father said, "How do you know that this isn't good fortune?"

Another year passed, and the barbarians invade the frontier. All the able-bodied young men were conscripted, and nine-tenths of them died in the war. 

Thus good fortune can be disaster and vice versa. Who can tell how events will be transformed?

=)