Arrangement of the List in Gaius’s and Justinian’s Institutes

There is a grouping of the contracts into four classes. The differenti­ation is based upon the way in which the contract is made. That is, upon the nature of the event which brings it into being.

Etprius videamus de his quae ex contractu nascuntur. Harum autem quattuorgenera sunt: aut enim re contrahitur obligatio aut verbis aut litteris aut consensu.

First let us consider those that arise from contract. Of such there are four genera: for an obligation by contract arises either re [by delivery of a res: real contract], by words [verbal contract], by writing [literal contract] or by consent [consensual contract].

You will see from Zulueta’s translation that the class of contracts �re’ does not slip easily into English. That will be considered in more detail later. The others are clear enough. By Justinian’s time, the membership of the category �re’ had slightly changed and the literal contract had barely any existence. Of the eight contracts mentioned as dominating the entire picture, sale, hire, partnership and commission (mandate) are grouped as consensual, requiring only agreement in order to become binding; and loan for consumption, loan for use, deposit and pledge are Justinian’s contracts �re, requiring the delivery of a thing to become binding. Stipulatio on its own accounts for all but the whole of the category verbis, requiring oral words. The contract by writing has not found a place in this introduction. It was never important. That is not the same as saying that writing itself was never important, as we shall see.

This fourfold division of contracts makes no mention of some praetorian additions to the list which were stable enough to have names or of the doctrine of innominate contracts which has already been mentioned.

The common law has nothing to do with this fourfold list—re, verbis, litteris, consensu—and at first sight seems to reject entirely the approach through specific contracts identified by content. It certainly starts on the other foot. If you ask it, Which promises are binding at law?, the answer comes in two parts, both of which are content-free: either you put your promise in writing and, having sealed it, deliver the sealed writing as your deed; or you promise in exchange for some consider­ation. What is a �consideration’? Something—anything—asked for and given as the price of the promise, a counter-promise, a giving or some other doing or not doing. This two-part answer is beginning to look shaky. Perhaps it is time to add a third part: or you promise in such a way as to induce detrimental reliance, in which case you will be bound, on the ground of estoppel, after there has been some such reliance. But even this third addendum still speaks in general terms, of a mode of becoming bound rather than of a promise binding by reason of its specific content. The picture remains all of one piece: promises, gen­erally, become binding when made by deed, supported by consider­ation or followed by detrimental reliance.

If one wanted to challenge the smoothness of this, the way would be to say that the doctrine of consideration is not really a general test at all but merely a rather wide �specific contract’ test. For what it says is that �bargains’ are binding. The nit-picking answer is that, even so, that has no reference to the content of the undertakings, which remain infin­itely various. The more liberal answer is that the line between general tests and specific tests is admittedly not clearly marked, and that there is something to be said for the view that a �bargain’ could be described as belonging to the specific contract approach, though it certainly includes far too much matter to be useful in working out the incidents of particular transactions.

Common lawyers are educated to believe in the generality of this law of contract. And that is not wrong. So far as concerns parol contracts it has all been worked out, at least since the early seven­teenth century, in one action, the action of assumpsit, in which, boiled down to essentials, the plaintiff's allegations were that in con­sideration of such and such the defendant promised such and such (assumpsit) but wickedly broke his promise. The text of the one action structured the whole development. The deed was a survival from an earlier time, useful for making gratuitous promises binding but peripheral to the main business. And promissory estoppel is a new­comer, still peripheral and indeed hardly at cross-purposes with the established core.

But this picture of one central and two peripheral tests all of the same �general' kind is partly misleading. The common law has also had to generate packages of rules for specific contracts. The obvious case is sale of goods, which has a little code to itself. But Volume II of Chitty on Contracts reveals that sale is only the most prominent example. The chapter headings there closely resemble the Roman list. Agency and bailment need special mention. The contract of employment has become a specialism. Hire-purchase has its own rules. Statutory control has accelerated what the common law was already doing. The result is that the general law which is still learned under the heading of contract is hardly more than an introduction, an indispensable foundation of principle but nothing like the whole story.

For all this it remains true that the basic orientation of the two systems is different. The Roman way was to throw up an archipelago of contractual islands in the sea and then to wonder what to do about people left in the water. The common law of contract rose out of the sea in one piece, or one large and two small, but was then too flat and had laboriously to build its high places.

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