There is disclosed in an example a computing apparatus for assigning an entropy score to a document to be added to a corpus in a first temporal state having a first corpus entropy, having one or more logic elements, including at least one hardware logic element, providing a classification engine to: receive the document to be added to the corpus; add the document to the corpus, creating a second temporal state of the corpus; compute a second corpus entropy for the second temporal state, based at least in part on a morphism; and assign the document a gentropy score based at least in part on a difference between the first corpus entropy and the second corpus entropy.