Computer grading will destroy our schools (says a humanist whose appeal to the humanities will be ignored by technologists)

True enough. Writing was never of any application towards the simple pass or fail techniques of grading. You simply cannot condense grammatical and conceptual information into numbers.

Writing is the art of seducing one's imaginative faculties to inform, teach and encourage the reader to think critically and make connections. Likewise, as the length of a piece grows, the stringency to grammar matters less, instead favouring the world you create in their minds. Even long technical documents must follow a conceptual succesion from one thought to the next. The greatest of writing tends to have the greatest command over this flow of concepts.

Creative writing evokes a dream world with the concepts. Informative writing evokes a clear image of the topic. Essentially, a computer, until shown to have subjective, independent opinions of a similar nature to the human flow of thought, can never be trusted to grade writing or provide feedback. This is especially obvious when it is taken into account that these grading systems use arbitrary information, such as amount of words and references to keywords.

Human thought is what writing embodies, and thus, only a computer capable of human thought may appreciate and judge the effectiveness of a piece of writing. I have yet to see computers operate on the same principles as human thought; we have only created complex analytical devices. We operate through arbitrary electrical signals that begin to encode the world around us with a unique pattern. Computers however, are not yet able to 'grow'. Human thought arises from the complex pattern of interactions between brain cells and the majority of those cells do not act as direct input/output. An algorithm, by definition, explicitly correlates an output with an input. Sentience in AI can presumably only derive from neural networks.