They are speculating on the imponderables of the future.

他们猜测着未来难以估算的事情。

We can't predict the outcome. There are too many imponderables.

我们无法预测结果。难以逆料的情况太多了。

We breathe the same air breathed by earlier generations, who pondered the same imponderables and sometimes made great art about those imponderables.

我们呼吸着上一代人呼吸过的空气，他们与我们一样揣摩过那些永远揣摩不出什么的东西，并且常常为了它们创造出不朽的艺术作品。

It is certainly hard to spot bubbles; but central Banks already grapple with other imponderables, such as the size of the output gap or the level of structural unemployment.

识别经济泡沫开始形成当然有难度，但央行已经有过处理其他不可预知事件的经验，像衡量产出缺口的大小或结构性失业率的水平。