合同本质上是不完全的，因为不可能预见所有未来的偶然事件。

The capacity of the human mind for formulating and solving complex problems is very small compared with the size of the problems whose solution is required for objectively rational behavior in the real world.

孔子说：“《诗经》三百首，用一句话可以概括，即：‘思想纯洁’。”