Johnson-Laird (1983) explained that cognitive psychologists have discovered that verbatim memory of a sentence typically persists only for a few seconds, in what is called short-term or working memory. Once its meaning has been apprehended the sentence is discarded like a booster rocket. Something similar seems to be true of individual sentence meanings. When a hearer is asked about the contents of a talk some time afterwards, the hearer’s sentences rarely stand in a one-one correspondence to those of the speaker. Instead, the hearer relies on his or her internalized representation of the content. This representation is constructed incrementally as the speech unfolds. Often, as Johnson-Laird (1983) has emphasized, it is a kind of model of the subject matter rather than a set of propositions. That is, unlike a purely discursive representation, it bears a structural resemblance to its subject matter, which may amount to isomorphism.