这些东西是人的肉眼看不见或观察不到的。

These things do not fall under human sight or observation.

youdao

不过，如果观察不到任何现象或预测不可靠。

If, however, observations cannot be made or the predictions are unreliable.

youdao

因此我们现在可以看出，在每次测量结果中有些模态是观察不到的。

So now we can see that the modes cannot be seen in every measurement.

youdao

Why is it that we're never observing this, for example, why is it the table doesn't diffract as we bring it through the door?

那么为什么我们,从来观察不到它呢，举个例子，搬动一个桌子穿过门,它为什么不衍射呢？

麻省理工公开课 - 化学原理课程节选

Let's call someting invisible not only it can't be seen, not only it can't be observed, but it can't be detected at all.

让我们把一些不仅是看不见的,不仅是观察不到的，而且是完全检测不到的，东西称为无形的。

耶鲁公开课 - 死亡课程节选

Two, different possibility, can't be observed.

第二个不同的解释，观察不到的。

耶鲁公开课 - 死亡课程节选