  The Posterior Analytics was little known in the twelfth century, despite James of Venice's translation, then. Though earlier discussions are to be noted, such as that of Richard Rufus (see Rega Wood (1996)), the work first enters into the Western tradition in a serious way in the commentary of Robert Grosseteste (1175-1253), written around 1230. Grosseteste applies the theory in the Posterior Analytics to itself, presenting it as a demonstrative science of demonstration. Thus he suggests that Aristotle first gives a definition of demonstration, a syllogism producing scientific knowledge, and a definition of scientific knowledge, and then, in a series of syllogisms, deduces the properties that a demonstration must have, first considered in itself as a free-standing syllogism, then considered in relation to other demonstrations, and finally considered as it is part of a science. The second book of the work, he claims, discusses the art of definition as the way to discover demonstrations, and how it is that definition occurs as the middle term and the cause of the truth of the conclusion, in a demonstration. He finds thirty-two scientific conclusions in each of the two books, and his list of conclusions forms the standard summary of the work for many later writers. This analysis is most plausible in the beginning of Book I, and the initially structured presentation degenerates to a mere list of points made, often with little evident deductive structure, in the discussion of the latter part of Book I and in Book II. Many portions of the book are treated, plausibly enough, as ancillary to the deductive science, concerned, for instance, with disproving common errors.