An explanation is simply that which allows for the object's intelligibility, which could in turn be claimed to be necessary in any justified argument about such an object(s). For example, the premise 'all swans are birds' and the conclusion 'all swans grow feathers', seems to require more primary understandings, namely the understanding of the terms (like 'swans', 'birds', and 'feathers') in the argument. Not being mere brute facts (so to say, not merely being understood in the fact of their being), such terms are able to be rationally discussed (as in having something more which can be said of them besides the fact that they are, so as to say that they are in a certain way, as possessing an explanation, or nature, or essence), which is evidenced in the purpose and conclusion of the argument. If swans being birds was mere brute fact, than it means that 'swans having feathers', which is the conclusion of the argument, is also a mere brute fact. As such, there is nothing more to be said about such facts, such as any relation they hold to anything else, including the relation between 'all swans being a bird' and 'all swans growing feathers'. But this relation is precisely what allows for the argument.
The same would seem to go with non-inferential arguments as well, and indeed with any argument that has terms that are supposed to follow from other terms (so an attack upon induction won't do). This seems to imply that any argument presupposes its subjects to have some explanation as to their being that is likely distinct in some manner from the fact of their being, as is evidenced in the necessity of understanding a term's intelligibility (or essence) for an argument, while not necessarily requiring to know if it is at all (unless the argument is about such a thing's existence). It is the explanation that allows for the substance of the argument's very relation between the premise and the conclusion; for example, since swans are birds, that means that swans are creatures that do naturally grow feathers, precisely because feathers are things that are grown by birds. Understanding the terms requires understanding the relation between them, which is allowed only in reference to such terms' explanations. However, is this analysis valid, and if not, what are its problems and/or limitations? Does it apply to all arguments?