The father sent his four sons each to look at a pear tree in a different season to teach them not to judge things too quickly. The first son saw it in winter and said it was ugly, while the second in spring said it was promising. The third in summer said it was beautiful, and the fourth in fall said it was full of life. The father explained they were all right because each saw only one season, and the true essence of something can only be known after all seasons.