The weak point he's highlighting isn't in processing the ADT itself. The problem is that there's a loss of semantic meaning about the information stored in the

The weak point he's highlighting isn't in processing the ADT itself. The problem is that there's a loss of semantic meaning about the information stored in the ADT. i.e. The ADT itself cannot dictate that the semantic structure of the information it stores is correct even though it may represent a well formed "Document"