提前思考

Terence Tao 2007-05-06

提前思考

比失明更糟糕的是,能看见却没有远见。 — 海伦·凯勒

人们很容易陷入某项工作的细节中,而忘记自己实际在做的事情的目的;因此,时不时停下来回想一下追求某个特定目标的原因是很有好处的。

例如,如果你出于某种原因试图证明一个引理,花点时间问自己一些问题,比如:

  • 如果引理被证明了,它将如何被使用?
  • 引理的哪些特征对你来说最重要?
  • 一个较弱的引理是否足够?
  • 是否有更简单的引理表述方式?
  • 如果某个假设在实践中似乎难以获得,是否值得尝试省略该引理的假设?

通常,在真正证明引理之前,其确切表述尚不明确,但即使细节尚未完成,你也应该能够从了解引理的形式中获得这些问题的一些部分答案。

这些问题可以帮助你在投入过多时间尝试证明之前,将引理重新表述为最优形式,从而使你能够更有效地利用研究时间。

同样的原则也适用于比引理更小的规模(例如,当试图证明一个小论断或执行冗长的计算时)和比引理更大的规模(例如,当试图证明一个定理、解决一个研究问题或追求一个研究目标时)。

另请参阅”问自己愚蠢的问题”。

Think ahead

Worse than being blind, is to see and have no vision. — Helen Keller

It is really easy to get bogged down in the details of some work and not recall the purpose of what one is actually doing; thus it is good to pause every now and then and recall why one is pursuing a particular goal.

For instance, if one is trying to prove a lemma for one reason or another, take a few moments to ask yourself questions such as:

  • If the lemma were proven, how would it be used?
  • What features of the lemma are most important for you?
  • Would a weaker lemma suffice?
  • Is there a simpler formulation of the lemma?
  • Is it worth trying to omit a hypothesis of the lemma, if that hypothesis seems hard to obtain in practice?

Often, the exact statement of the lemma is not yet clear before one actually proves it, but you should still be able to get some partial answers to these questions just from knowing the form of the lemma even if the details are not yet complete.

These questions can help you reformulate your lemma to its optimal form before sinking too much time into trying to prove it, thus enabling you to use your research time more efficiently.

The same type of principle applies at scales smaller than lemmas (e.g. when trying to prove a small claim, or to perform a lengthy computation) and at scales larger than lemmas (e.g. when trying to prove a theorem, solve a research problem, or pursue a research goal).

See also “ask yourself dumb questions”.