MacWhinney argues that the logical problem of language acquisition is no longer. It was a problem back in the 1970s when the guiding premises of the field were that language structure is highly abstract, that the child's input is a poor source of information about grammar, and that the child's learning mechanisms are inadequate to bridge the gap between the input the child receives and the grammar the child acquires. Now, however, we have new linguistic theories which show that language structure is not abstract but arises from cognition, and we have evidence that input is a rich source of information, and we have reason to believe that the child has a powerful array of learning procedures at his or her disposal. The gap between input and acquisition thought to exist in the 1970s has been closed, and thus, MacWhinney argues, there is no need to attribute innate linguistic knowledge to the child.