This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Original impossibility of fact is ordinarily divided into two classes, one of which includes contracts in which the impossibility is apparent on the face of the contract, at least to one who has the knowledge with which the law assumes all reasonable human beings to be possessed, irrespective of the knowledge which the specific individual actually possesses in the specific case.1 The other examples which are usually given by way of illustration, such as a contract to secure a unicorn, or to touch the sky, or to go from London to Rome in three hours, are usually taken from Roman law or from early English illustrations, which were possibly borrowed in part through Bracton from Roman law.2 Some of the illustrations found in the earlier books with reference to the period within which a journey is to be accomplished would be regarded as perfectly possible under modern conditions.
1 See Sec. 2660 et seq.
2 See Sec. 2673 et seq. 3 See Sec. 2669 et seq.
4 See Sec. 2673 et seq. and 2711 et seq.
5 See Sec. 2714 et seq.
6 See Sec. 2669 et seq. and 2681 et seq. 7 See Sec. 2672 and Sec. 2697 et seq.
8 See Sec. 2669 et seq. and 2681 et seq.
9 See Sec. 2697 et seq. 10 See Sec. 2672.
11 See Sec. 2669 et seq.
12 See Sec. 2672.
13 See Sec. 637 et seq.
From the nature of the case, it is far easier to suggest hypothetical illustrations than actual adjudications. A covenant to perform an act before the covenant itself is made,3 or to perform conjurations,4 are actual illustrations of the application of this doctrine.
It is not necessary, however, to invoke the theory of responsibility to explain cases of this sort. If the covenant is impossible of performance on its face, it can not operate as a consideration for the covenant of the adversary party, which is made in consideration of such impossible covenant. Cases of this sort are therefore really cases in which the promise of one party is gratuitous in legal effect, because the promise of the other party is unenforceable; but it is unenforceable, however, because it is impossible on its face.