* * * * NOTE FROM THE MODERATOR TO OLI AND SCIFES * * * *
Please stop feuding. I'm not even quite sure what the problem is, but it's certainly not serious enough to merit tossing around words like "stupid" in a place of scholarship.
"Inability," like "ability," can take a definite or indefinite article, but it can also be used as a commodity noun like "love" or "water" with no article.
The sentence, "The latter [statement] is inability to accept the concept," does indeed have a flaw or two, but there's nothing wrong with it grammatically. The problem is that the sentence itself is an expression of inability (or the inability), but it is not itself inability (or the inability.) That's a pretty subtle error by today's standards, and it is definitely one of form, not comprehensibility. I might not bother to correct it, depending on the formality of the document I'm editing.