Language Point 53

Descartes had unsuccessfully searched for certainty, first in the world of books, and then in the world of men. (Para. 6)
Meaning: Descartes had been not successful in searching for life with no doubt to it; he first searched for it in piles of books and then from crowds of people.
search for: try to find; look for
They searched for the missing boy everywhere, but they could not find him.

他們到處尋找那個走失了的小孩，但仍沒能找到。
Scientists searched for the cause of the disease.

科學家們千方百計尋找這種疾病的病因。
We often waste our time searching for keys, glasses and other small objects that are in continuous use.

我們常常浪費時間去找那些常用的東西，如鑰匙、眼鏡和其他小東西。
certainty: n. the fact, quality, or state of being certain
I have told them with absolute certainty there'll be no change.

我明白無誤地告訴他們不會有什么變化。
There is little certainty about the present state of the US economy.

目前美國的經濟狀況有許多不定的因素。