否定证据 negative evidence

指能够证明某一事实不存在或没有发生的证据，如证人所作的关于自己没有看到某事发生或没有听到某种情况的证言。通常否定证据比肯定证据〔positive evidence〕的证明效力要弱，但有时证人所作的否定性陈述也可以具有与肯定证据同样的证明效力，这要根据证人能够看到事件发生的机会的大小来确定，如证人观看了整场比赛且没有看到看台上发生骚乱的证言就比仅说明没有看到骚乱的证言要更有证明效力。

In language acquisition, negative evidence is information concerning what is not possible in a language. Importantly, negative evidence does not show what is grammatical; that is positive evidence. In theory, negative evidence would help eliminate ungrammatical constructions by revealing what is not grammatical. Direct negative evidence refers to comments made by an adult language-user in response to a learner's ungrammatical utterance. Indirect negative evidence refers to the absence of ungrammatical sentences in the language that the child is exposed to. There is debate among linguists and psychologists about whether negative evidence can help children determine the grammar of their language. Negative evidence, if it is used, could help children rule out ungrammatical constructions in their language. 具体例句如下，可供参考：

例句1

Negative evidence is a concept that deserves greater currency in the intellectual trades and popular culture. Negative evidence helps prove that something did not occur. University registrars routinely use negative evidence when they run a transcript check to prove that someone never got a degree at their university.

否定证据是一个值得在智力交易和流行文化中更广泛传播的概念。否定证据有助于证明某事没有发生。大学注册官在进行成绩单检查时，通常会使用否定证据来证明某人从未在他们的大学获得学位。

例句2

Negative evidence is the epistemic dual to positive evidence. It is just that evidence that tends to prove a negative. So it collides headfirst with the popular claim that you cannot prove a negative. A more sophisticated version of the same claim is that absence of evidence is not evidence of absence.

否定证据是积极证据的认知对偶。只是那个证据倾向于证明是否定的。因此，它与流行的说法相冲突，即你不能证明一个否定。同一个说法的一个更复杂的版本是，缺乏证据不是说不存在的证据。

例句3

Courts often allow negative evidence if the proponent lays a proper foundation for it. The opponent must also not have shown that the lack of evidence involved something improper or untrustworthy. A convenience store’s videotapes of a robbery can give compelling negative evidence that a suspect did not take an active part in the robbery. But the video recordings would have to cover a sufficient portion of the store and its parking lot. The cameras must also have run continuously throughout the robbery.

如果支持者为否定证据奠定了适当的基础，法院通常会允许否定证据。对手肯定也没有证明证据的缺乏涉及到不正当或不可信的事情。便利店的抢劫录像带可以提供令人信服的否定证据，证明嫌疑人没有积极参与抢劫。但是录像必须覆盖商店和停车场的足够大的部分。在整个抢劫过程中，摄像机也一定是连续运行的。

例句4

The strength of negative evidence tends to fall off quickly with the size of the search area. That is why we cannot yet technically rule out the existence in the deep seas of kraken-like creatures that can drag ships down to their doom. The ocean contains more than three hundred million cubic miles of water. High-resolution sonar has mapped only a fraction of it. That mapping itself has only been a snapshot and not an ongoing movie. It is far from diligent search of the whole volume.

否定证据的强度往往会随着搜索区域的大小而迅速下降。这就是为什么我们还不能从技术上排除在深海中存在类似克拉肯的生物，这些生物可以将船只拖向毁灭。海洋包含超过三亿立方英里的水。高分辨率声纳只绘制了其中的一小部分。这种映射本身只是一个快照，而不是一部正在进行的电影。这远远不是对整个海洋的精密搜索。