Pacts of this sort are always enforced under the advanced Roman jurisprudence. The principle is merely the principle of the Consensual. Contract carried to its proper consequence; and, in fact, if the technical language of the Romans had been as plastic as their legal theories, these Pacts enforced by the Praetor would have been styled new Contracts, new Consensual Contracts.
Legal phraseology is, however, the part of the law which is the last to alter, and the Pacts equitably enforced continued to be designated simply Praetorian Pacts. It will be remarked that unless there were consideration for the Pact, it would continue nude so far as the new jurisprudence was concerned; in order to give it effect, it would be necessary to convert it by a stipulation into a Verbal Contract.
The extreme importance of this history of Contract, as a safeguard against almost innumerable delusions, must be my justification for discussing it at so considerable a length. It gives a complete account of the march of ideas from one great landmark of jurisprudence to another. We begin with Nexum, in which a Contract and a Conveyance are blended, and in which the formalities which accompany the agreement are even more important than the agreement itself. From the Nexum we pass to the Stipulation, which is a simplified form of the older ceremonial.
The Literal Contract comes next, and here all formalities are waived, if proof of the agreement can be supplied from the rigid observances of a Roman household. In the Real Contract a moral duty is for the first time recognised, and persons who have joined or acquiesced in the partial performance of an engagement are forbidden to repudiate it on account of defects in form.
Lastly, the Consensual Contracts emerge, in which the mental attitude of the contractors is solely regarded, and external circumstances have no title to notice except as evidence of the inward undertaking. It is of course uncertain how far this progress of Roman ideas from a gross to a refined conception exemplifies the necessary progress of human thought on the subject of Contract. The Contract-law of all other ancient societies but the Roman is either too scanty to furnish information, or else is entirely lost; and modern jurisprudence is so thoroughly leavened with the Roman notions that it furnishes us with no contrasts or parallels from which instruction can be gleaned. From the absence, however,. the of everything violent, marvellous, or unintelligible in changes Ihave described, it may be reasonably believed that the history of ancient Roman Contracts is, up to a certain point, typical of the history of this class of legal conceptions in other ancient societies. But it is only up to a certain point that the progress of Roman law can be taken to represent the progress of other systems of jurisprudence. The theory of Natural law is exclusively Roman. The notion of the vinculum juris, so far as my knowledge extends, is exclusively Roman. The many peculiarities of the mature Roman law of Contract and Delict which are traceable to these two ideas, whether singly or in combination, are therefore among the exclusive products of one particular society. These later legal conceptions are important, not because they typify the necessary results of advancing thought under all conditions, but because they have exercised perfectly enormous influence on the intellectual diathesis of the modern world.
I know nothing more wonderful than the variety of sciences to which Roman law, Roman Contract-law more particularly, has contributed modes of thought, courses of reasoning, and a technical language. Of the subjects which have whetted the intellectual appetite of the moderns, there is scarcely one, except Physic, which has not been Altered through Roman jurisprudence. The science of pure Metaphysics had, indeed, rather a Greek than a Roman parentage, but Politics, Moral Philosophy, and even Theology found in Roman law not only a vehicle of expression, but a nidus in which some of their profoundest inquiries were nourished into maturity. For the purpose of accounting for this phenomenon, it is not absolutely necessary to discuss the mysterious relation between words and ideas, or to explain how it is that the human mind has never grappled with any subject of thought, unless it has been provided beforehand with a proper store of language and with an apparatus of appropriate logical methods. It is enough to remark, that, when the philosophical interests of the Eastern and Western worlds were separated, the founders of Western thought belonged to a society which spoke Latin and reflected in Latin. But in the Western provinces the only language which retained sufficient precision for philosophical purposes was the language of Roman law, which by a singular fortune had preserved nearly all the purity of the Augustan age, while vernacular Latin was degenerating into a dialect of portentous barbarism. And if Roman jurisprudence supplied the only means of exactness in speech, still more emphatically did it furnish the only means of exactness, subtlety, or depth in thought. For at least three centuries, philosophy and science were without a home in the West; and though metaphysic and metaphysical theology were engrossing the mental energies of multitudes of Roman subjects, the phraseology employed in these ardent inquiries was exclusively Greek, and their theatre was the Eastern half of the Empire. Sometimes, indeed, the conclusions of the Eastern disputants became so important that every man's assent to them, or dissent from them, had to be recorded, and then the West was introduced to the results of Eastern controversy, which it generally acquiesced in without interest and without resistance.