Symbols are of three classes: terms, which call attention to things or quasi-things; propositions, which declare facts; and arguments, which profess to enlighten us as to the rational connections of facts or possible facts.
From an early/discarded draft
An Argument is a sign whose interpretant represents its object as being an ulterior sign through a law, namely, the law that the passage from all such premisses to such conclusions tends to the truth. Manifestly, then, its object must be general; that is, the Argument must be a Symbol. As a Symbol it must, further, be a Legisign. Its Replica is a Dicent Sinsign.
A representamen is either a rhema, a proposition, or an argument. An argument is a representamen which separately shows what interpretant it is intended to determine. A proposition is a representamen which is not an argument, but which separately indicates what object it is intended to represent. A rhema is a simple representation without such separate parts.
I […] define an argument as a sign which is represented in its signified interpretant not as a Sign of the interpretant (the conclusion) [for that would be to urge or submit it] but as if it were a Sign of the Interpretant or perhaps as if it were a Sign of the state of the universe to which it refers, in which the premisses are taken for granted.
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 the latter.)
I have already defined an argument as a sign which separately monstrates what its intended interpretant is, and a proposition as a sign which separately indicates [what] its object is; and we have seen that the icon alone cannot be a proposition while the symbol alone can be an argument. [—] It will be observed that an argument is a symbol which separately monstrates (in any way) its purposed interpretant.
In their relations to their Triadic, i.e. intended or adaptational Interpretants, Signs may, 1st, determine those interpretants, merely in the sense that, if the Interpretants represent the Objects as the Signs themselves do they are such Interpretants as are intended. Such is an ideal statuette, and exclamation of surprise, a noun, whether common or proper. 2nd, Signs may be adapted to compelling or tending to compel the determination of their intended interpretants, such is a portrait with the name of the person represented under it, such is a weather-cock in a good breeze. 3rd, Signs may be adapted to determining a particular interpretant logically. Names: Rheme, Dicisign, Argument.
A familiar logical triplet is Term, Proposition, Argument. In order to make this a division of all signs, the first two members have to be much widened. [—] As the third member of the triplet, I sometimes use the word Delome […], though Argument would answer well enough. It is a Sign which has the Form of tending to act upon the Interpreter through his own self-control, representing a process of change in thoughts or signs, as if to induce this change in the Interpreter.
An argument […] is nearly equivalent to “premiss” or “copulate premiss,” i.e. a body of premisses having a single intention, and is a known or pretended fact which is intended to serve as a Sign of the reality of another fact, its Conclusion.