In these two segments of The World, the most distinctive aspects of Descartes' views are less the central focus than they are at the beginning of the Treatise on Light and the end of the Treatise on Man. As you read them, you should, of course, watch for interesting details of his system; and they will be what we will spend most time discussing. But you should also think about a couple more general questions:

• How closely tied are his explanations of particular phenomena to such fundamental principles as his catalogue of elements and his laws of motion? In his Discourse on Method, he said, "the power of nature is so ample and vast, and these principles so simple and general, that I have hardly observed a single particular effect which I cannot at once recognize as capable of being deduced in many different modes from the principles, and that my greatest difficulty usually is to discover in which of these modes the effect is dependent upon them" (part VI, Veitch tr.). Do you think it would be the case not only that many different explanations of observed phenomena would be possible but also that Descartes would equally well be able to explain phenomena contrary to those observed (i.e., that observation might not be sufficient to falsify his basic principles)?
• Is the sort of explanation Descartes is offering here really scientific? After ch. 7, he does not claim to deduce his explanations from fundamental principles. And, while the problem of choosing among possible explanations that was described in the Discourse on Method was supposed to be solved by conducting experiments. He says about this, "I am now in a position to discern, as I think, with sufficient clearness what course must be taken to make the majority those experiments which may conduce to this end: but I perceive likewise that they are such and so numerous, that neither my hands nor my income, though it were a thousand times larger than it is, would be sufficient for them all; so that according as henceforward I shall have the means of making more or fewer experiments, I shall in the same proportion make greater or less progress in the knowledge of nature" (part VI, Veitch tr.). Such experiments apparently didn't provide grounds for the account we are reading since the Discourse on Method was written after he abandoned work on The World.