orientation and Lord Diplock’s comment might be said to be one starting point. Senior judges are now talking less and less in terms of a twofold division of contract and tort, and more in terms of a law of obligations, and doctrine is adopting the same attitude. This reorientation is partly the result of the increasing acceptance of restitution as an independent third category and, possibly, partly the result of a growing influence of Europe on the English legal mind. Nevertheless, the transplanting of a law of obligations category does not come without considerable conceptual problems. 2 Real and personal rights. In civilian legal thought, the law of obligations is part of a highly systematic structure of legal rights which rigidly distinguishes rights in rem from rights in personam (see the Roman jurist Paul, above). The law of obligations acts as the basis for all personal rights and thus, as a category, stands in contrast to the law of property; or, put another way, owing is kept quite distinct from owning. Such rigid systematics are inapplicable to the common law, since not only is much of the law of property to be found in contract and tort (see, for example, Torts (Interference with Goods) Act 1977), but the law of restitution is a mixture of personal and proprietary claims (see, for example, pp 794–819). A law of obligations, for the foreseeable future, can never have the same meaning for a common lawyer as it does for a continental jurist. 3 General principles of liability. Another characteristic of the continental codes is that liability in the law of obligations is expressed through general principles (and see, now, PECL and UNIDROIT). Of course, an important distinction is made between contractual and non-contractual liability. However, the notion of liability itself, that is to say, non-performance of an obligation, tends to be viewed as an abstract notion founded not only upon specific contract or delict rules but also upon general ideas, as we shall see, such as fault and impossibility of performance (see, for example, PECL, Art 8:101). In the common law, it is often much harder to isolate such general principles, since the basis of civil liability has grown up around different types of forms of action and different species of remedy. Certainly, there are generalities, as we have seen in Chapter 3, with respect to the remedy of damages (for example, mitigation) and fault itself is now more or less a general principle of liability (Donoghue v Stevenson, p 65; Supply of Goods and Services Act 1982, s 13). But the forms (causes) of action can still exert an influence, with the result that it remains difficult to talk about liability in terms of general obligations. Thus, Act of God, breach of contract, breach of duty of care, frustration, self-induced frustration, contributory negligence, mitigation, novus actus interveniens, remoteness and so on tend to be approached as discrete rule areas. Put another way, there is little symmetry in English civil liability (cf PECL, Art 8:108).