Full Idea
Words like 'this', 'that', 'I', 'you', enable us to convey meanings which words alone are incompetent to express; they stimulate the hearer to look about him.
Gist of Idea
Indexicals are unusual words, because they stimulate the hearer to look around
Source
Charles Sanders Peirce (Reasoning and the Logic of Things [1898], II)
Book Reference
Peirce,Charles Sanders: 'Reasoning and the Logic of Things', ed/tr. Ketner,K.L. [Harvard 1992], p.128
A Reaction
Peirce was once of the first to notice the interest of indexicals, and this is a very nice comment on them. A word like 'Look!' isn't like the normal flow of verbiage, and may be the key to indexicals.