A sign is also intended to determine, in a mind or elsewhere, a sign of the same object; and this interpretant of the sign may be the very sign itself; but as a general rule it will be different. It is a perfection in a sign separately to signify its intended interpretant. If it does this, it becomes and argumention or argument. (Some pedants insist on the former word; but the very best usage supports theĀ latter.)
http://www.commens.org/dictionary/entry/quote-foundations-mathematics-r-3