Essentially the law of tort is designed to prevent people from deviating from those particular rules which allow systems to work well, namely the rules that protect the autonomy of the person, namely the rules that protect the property you've acquired, either through original possession or through voluntary transaction. The question is, "What are the kind of threats to these things, and how does the legal system deal with them?” You can divide the threats into two very broad categories. The first category is theft and the second category is destruction. The difference between them is very clear. In a case of theft, what happens is something which you owned now is in the hands of somebody else, and it's a live asset that can be transferred to other individuals, or consumed in one form or another. If you are talking about destruction of property, the thing ceases to exist, and the question of subsequent transfers and manipulations, in effect, is put to one side. If you're thinking about theft, for the most part, if somebody deliberately steals something from you, there's very little by way of an affirmative defense that you can do to excuse, or to justify, the theft in question. If it turns out your property is destroyed, these questions of excuse or justification become much larger: Did you put yourself in harm's way? And did you trespass on somebody else's land? Did you consent to the particular risk in question? Are all very live issues. And so, when you go through Gaius, he starts in effect and goes through the contractual obligations, and then what he does immediately is he switches over to the delict side, or the tort side. Delict is kind of a funny word, which means it's part criminal, for which mens rea, a guilty mind, tends to be relevant, and part tort, which means we look at the consequences of the defendant's act, and less at the motivation that put it into place. The question is how do we put all of these things together?