in the civil law, an obligation, whereby the effects of a debtor are made over to his creditor, to secure his debt. The word comes from the Greek ὑποθέσις, a thing subject to some obligation; of the verb ὑποθέσαι, ἐπιπονοῶ, "I am subjected;" of ὑπό under, and ἐπιπονοῶ, "I put."

As the hypotheca is an engagement procured on purpose for the security of the creditor, various means have been made use of to secure to him the benefit of the convention. The use of the pawn or pledge is the most ancient, which is almost the same thing with the hypotheca; all the difference consisting in this, that the pledge is put into the creditor's hands; whereas, in a simple hypotheca, the thing remained in the possession of the debtor. It was found more easy and commodious to engage an estate by a civil covenant than by an actual delivery: accordingly the expedient was first practised among the Greeks; and from them the Romans borrowed both the name and the thing: only the Greeks, the better to prevent frauds, used to fix something visible. The Cartesians take upon them to suppose what affections in the primary particles of matter they please; just what figures, what magnitudes, what motions, and what situations, they find for their purpose. They also feign certain unseen, unknown fluids, and endue them with the most arbitrary properties; give them a subtilty which enables them to pervade the pores of all bodies, and make them agitated with the most unaccountable motions. But is not this to set aside the real constitution of things, and to substitute dreams in their place? Truth is scarce attainable even by the surest observations; and will fanciful conjectures ever come at it? They who found their speculations on hypotheses, even though they argue from them regularly, according to the strictest laws of mechanics, may be said to compose an elegant and artful fable; but it is still only a fable.