Initial impossibility of stipulations

All the examples mentioned so far refer either to stipulation or to consensual sale. Impossibilium nulla obligatio est does not seem to have been discussed with regard to other contracts; as far as contractus re were concerned, such a discussion would, of course, have been a logical impossibility in any event, since they came into existence only with the handing over of the object.

The stipulation was invalid. No explanation is given for the result, and thus one is left to speculate. The stipulation was a contract stricti iuris, and the appropriate action was the condictio (certae rei). "Si paret N^m N^m A° A" hominem Stichum dare oportere, quanti ea rest est, tantam pecuniam iudex N^m N^m A° A° condemnato, si non paret, absolvito" was its formula. Condemnation, therefore, presupposed "that it appears that the plaintiff has to give the slave Stichus to the defendant". But how could this "appear" to be the case if the slave had ceased to exist at the time when the contract was concluded? To postulate a "dare oportere" under these circumstances was obviously not considered to be possible.^{[3470] [3471] [3472] Apart from that, a second prerequisite for condemnation was that the defendant's (object of) performance was capable of being evaluated in monetary terms ("quanti ea res est, tantam pecuniam"). In most, if not in all, cases of initial objective impossibility, an object of which the value could sensibly be estimated, was, however, lacking; for what is the value of a hippocentaurus, of a res extra commercium or of the corpse of a slave whom the parties had intended to transfer alive?91}

4.