Chunking makes writing hardScholars lose their moorings in the land of the concrete because of two effects of expertise that have been documented by cognitive psychology. One is called chunking. To work around the limitations of short-term memory, the mind can package ideas into bigger and bigger units, which the psychologist George Miller dubbed "chunks." As we read and learn, we master a vast number of abstractions, and each becomes a mental unit that we can bring to mind in an instant and share with others by uttering its name. An adult mind that is brimming with chunks is a powerful engine of reason, but it comes at a cost: a failure to communicate with other minds that have not mastered the same chunks. The amount of abstraction a writer can get away with depends on the expertise of his readership. But divining the chunks that have been mastered by a typical reader requires a gift of clairvoyance with which few of us are blessed. When we are apprentices in our chosen specialty, we join a clique in which, it seems to us, everyone else seems to know so much! And they talk among themselves as if their knowledge were conventional wisdom to every educated person. As we settle into the clique, it becomes our universe. We fail to appreciate that it is a tiny bubble in a multiverse of cliques. When we make first contact with the aliens in other universes and jabber at them in our local code, they cannot understand us without a sci-fi universal translator.