Full Idea
There is no greater impediment to the advancement of knowledge than the ambiguity of words.
Gist of Idea
The ambiguity of words impedes the advancement of knowledge
Source
Thomas Reid (Essays on Intellectual Powers 1: Preliminary [1785], 1)
Book Reference
Reid,Thomas: 'Inquiry and Essays', ed/tr. Beanblossom /K.Lehrer [Hackett 1983], p.129
A Reaction
He means that ambiguity leads to long pointless disagreements.