主题：【原创】今天的数学（系列） -- qiaozi

不知道真的是学理科的人逻辑严谨，还是这些年被数学害的（数学家在为新事物起名字方面的水平是臭名昭著的），和别人讨论的时候常常要停下来问一句：“Excuse me, but what do you mean by...?”因为关于同一个名词、同一个问题不同的人可能在说不同的东西。

其实，这种情况在社会科学里更常见。例如，大家在讨论“民主”的时候，有时候我会忍不住想问“Excuse me, but what do you mean by 民主?”美国的、还是欧洲的、还是某一本书里面讲的？几乎没有人会说民主不好，但是讨论在中国某些措施该不该实行、什么时候实行的时候，这里的民主恐怕还是精确一点好。同样的问题可以放到“人权”、“平等”等很多讨论中。大原则总是简单的，但是我们讨论的往往是那些模糊地带。没有一个清楚而统一的定义－－至少是在自己心里，这样空对空的讨论能走多远？

看过那本《The Hitchhiker's Guide to Galaxy》的朋友可能都记得４２这个数字。没看过的朋友可以看看下面的这一段节选，也许会和我一样有所触动。

``Alright,'' said Deep Thought. ``The Answer to the Great Question ...''

``Yes ...!''

``Of Life, the Universe and Everything ...'' said Deep Thought.

``Yes ...!''

``Is ...'' said Deep Thought, and paused.

``Yes ...!''

``Is ...''

``Yes ...!!!...?''

``Forty-two,'' said Deep Thought, with infinite majesty and calm.

``Forty-two!'' yelled Loonquawl. ``Is that all you've got to show for seven and a half million years' work?''

``I checked it very thoroughly,'' said the computer, ``and that quite definitely is the answer. I think the problem, to be quite honest with you, is that you've never actually known what the question is.''

``But it was the Great Question! The Ultimate Question of Life, the Universe and Everything!'' howled Loonquawl.

``Yes,'' said Deep Thought with the air of one, who suffers fools gladly, ``but what actually is it?''

A slow stupefied silence crept over the men as they stared at the computer and then at each other.

``Well, you know, it's just Everything ... Everything...'' offered Phouchg weakly.

``Exactly!'' said Deep Thought. ``So once you do know what the question actually is, you'll know what the answer means.''