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Keeping promises: the moral and legal obligation

Published online by Cambridge University Press:  02 January 2018

Samuel Stoljar*
Australian National University


It is often assumed that a promise is not legally enforceable unless, as a necessary though not sufficient condition, the promise is morally ‘obligatory’ or ‘binding’. If this assumption is correct, or can be shown to be tenable, highly interesting and important things follow for both legal and contract theory. Promise-keeping emerges as a moral obligation before it is a legal one, the legal duty becoming but a sanctionable extension of the moral obligation, its continuation so to speak by other means. There is thus no fundamental break separating moral from legal promises; for even a legal promise, particularly or most visibly one not covered by existing authority, cannot be fully justified as to why it ought to be kept without support from moral grounds. In the first three sections we therefore consider the moral reasons we may advance in support of an obligation to keep promises. In the last two sections we try to relate these moral considerations more specifically to contract law.

Research Article
Copyright © Society of Legal Scholars 1988

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1. On intuitionism, see generally Ross, W D, The Right and the Good (Oxford 1930)Google Scholar; pp 16ff, 43ff; A I Melden, On Promising (1956) 65 Mind 49, 65; D W Hamlyn, The Obligation to Keep a Promise (1962) 62 Proc Arist Soc 179, 189.

2. J L Austin, How to Do Things with Words, pp 51–2, suggests that to say ‘I promise’ but not to perform is parallel to saying ‘it is’ and ‘it is not’.

3. D Hume, A Treatise of Human Nature (Selby-Bigge, ed, Oxford) pp 516–17, 525. Yet compare a more recent defence of the ‘will obligating itself by M H Robins, The Primacy of Promising (1976); 85 Mind 321, 331.

4. H A Prichard, Moral Obligation (Oxford 1949); pp 169, 171.

5. J R Searle, Speech Acts (Cambridge 1969); p 175ff; ‘What is a Speech Act?’ in The Philosophy of Language, pp 39, 50; J Rawls, Two Concepts of Rules (1955) 64 Phil Rev 1; A Theory of Justice (Oxford, 1972) pp 344–5. The latter author's two accounts differ in significant ways, but the differences are not relevant here.

6. For these and other criticisms, see T Beardsmore, ‘Ought’ and Rules (1970); 45 Philosophy 240; D H Jones, Making and Keeping Promises (1966) 76 Ethics 287; R M Hare, ‘The Promising Game’ in P Foot, ed, Theories of Ethics (Oxford) p 115; L C Holborow, Promising, Prescribing and Playing-Along (1969) 44 Philosophy 149; J L Mackie, Ethics (Harmondsworth, 1977) pp 67ff; O Hanfling, Promises, Games and Institutions (1974) 75 Proc Aris Soc 13, 22.

7. O Hanfling, loc cit, pp 13 – 31.

8. A N Prior, Logic and the Basis of Ethics (Oxford 1949); p 52.

9. D Hume, Treatise of Human Nature, pp 522 – 3.

10. D N MacCormick, Voluntaty Obligation and Normative Powers (1972); 46 Arist Soc Suppl 59, 71–3.

11. F S McNeilly, Promises De-Moralized (1972); 81 Phil Rev 63, 71ff, 76–8.

12. ‘Ought’ and ‘obligation’ are here used interchangeably, though there are occasional differences between them. See, eg, D Locke, The Object of Morality, and the Obligation to Keep a Promise (1972); 2 Can Journ of Phil 135, 141 and passim..

13. See B H Slater, A Grammatical Point about Obligation (1978); 28 Phil Quart 229, 231, to whom I am indebted for some of these points.

14. C K Grant, Promising (1949); 58 Mind 359, 360.

15. See generally A M Quinton, Utilitarian Ethics (London 1973);. Two other ‘schools’, recently much discussed, sponsor aggregative standards of a somewhat similar kind. The ‘law and economics’ school argues for a test of (free) market efficiency for all legal results, including those relating to promises. The ‘critical legal studies’ movement calls for a sort of unflinching populism all legal rules should serve. Both schools, however, ultimately raise the same theoretical difficulties that utilitarianism projects.

16. Ross, op cit, pp 38 – 9.

17. John Austin, Lectures on Jurisprudence (4th edn, London 1879); pp i, 117 – 18.

18. G C Kerner, The Immorality of Utilitarianism (1971) 21 Phil Rev 36, 40-1; see also C Landesman, Promises und Practices (1966); 75 Mind 239, 242.

19. D Lyons, Forms and Limits of Utilitarianism (Oxford 1965); pp 119ff.

20. J Rawls, Two Concepts of Rules (1955); 64 Phil Rev 1, reprinted in P Foot, ed, Thories of Ethics, pp 144, 155ff.

21. For similar criticisms, see Lyons, op cit, pp 185ff; Kerner, op cit, p 41.

22. A type of promise causing special problems for utilitarians is the so-called deathbed or desert-island promise. If A promises B, who is dying on a remote island, that he (A) will give B's money to a jockey club after his death, but which A, after he himself is rescued, decides to give to a deserving hospital, Professor Smart, to whom we owe this example (cf J J C Smart, ‘Extreme and Restricted Utilitarianism’, in P Foot, ed, Theories of Ethics (Oxford 1967); pp 171, 178ff) thought that utilitarian theory might still direct A to transfer the money as B wished, provided we take into account the ill effects on A, due to his felt faithlessness to B. Still, it is difficult to see why A should have a bad conscience if, as a good utilitarian, he acts to optimum social advantage. How, in any case, are the respective utilities to be measured: how does one weigh the ill effects on a promisor against the needs of a hospital? For the lawyer the solution here should be obvious. Once the story comes out, A would be held to be a secret trustee holding the money for the club. In no case would A be allowed to apply B's money as if it were his own.

23. J Rawls, A Theory of Justice, pp 342K. It is sometimes said (cf Lyons, op cit, pp 188–9, 196–7) that while justice might fill some gaps, we should not try to force justice and fairness to do all the jobs for the whole of morality. Yet, whatever be the case for all of morality, we do need something of a general theory for so unified a field like promises. Lyons mentions another possible doctrine, that of fidelity, but does not define it further. But as Rawls shows (op cit, pp 346–8) fidelity is, in any event, not a separate option but a corollary of the fairness principle. Even more importantly, perhaps, fidelity is not an alternative to promise-keeping but closely akin to it, except that the person in a fiduciary position comes under an obligation by virtue of the office he assumes, whereas a promisor ought to perform according to the terms of his promise to the promisee. The fiduciary (trustee, agent, etc) has a duty to act faithfully in his principal's interests, while the promisor's good faith rather lies in the promise-keeping itself; for as a promisor he is not managing another's estate or transaction, though of course he may do that too.

24. For possibly some such suggestion see H LA Hart, Are There Any Natural Rights ? (1955); 64 Philos Rev 175.

25. This example combines Bainbridge v Firmstone (1838); 8 A & E 743 and Moss v Sweet (1851) 16 QB 493.

26. Recent developments in English law, whereby tort (in particular professional negligence) actions are employed to achieve ‘contractual’ (at any rate expanded contractual) results, again affirm their affinity: see, eg, Batty v Metropolitan Realizations (1978) QB 554; Midland Bank Trust Co v Hett, Stubbs & Kemp (1979) Ch 384; Junior Books Ltd v Veitchi Co Ltd (1982) 3 WLR 447; Rimmer v Liverpool Cig Council (1984); 1 All ER 930.

27. See Re Moore and Landauer Co (1921); 2 KB 519; also Behn v Burness (1863) 1 B & S 751; Arcos Ltd v Rowen (1933) AC 470. But these decisions, too, now seem under a cloud: Reardon Smith Line Ltd v Hansen Tangen (1976) 3 All ER 570.

28. Restatement, Contracts 2d, s 261, Comment d. Cases arising from the closure of the Suez Canal illustrate admirably what distinguishes merely impractical from fully impracticable contingencies: see, eg, The Eugenia (1964); 2 QB 226. Similar problems arise with regard to construction contracts delayed by a strike, as to which compare Davis Contractors Ltd v Fareham UDC (1956) AC 696 and Codelfa Construction Pty Ltd v State Rail Authority, NSW (1982) 149 CLR 337.

29. For an example of this in sale, see, eg, Re Fawcett and Holmes' Contract (1889) 42 Ch D 150. For an example in a charterparty, see Hong Kong Fir shipping Co Ltd v Kawasaki Kisen Kaisha Ltd (1962); 2 QB 26. The latter decision has been partly dissented from (cf Bunge Corpn v Tradax Export SA (1981) I WLR 711); but mainly as regards its phraseology or technique, not so much as regards its substantive result.

30. On implied terms, see generally J F Burrows, Contractual Co-operation and Implied Term (1968); 31 Mod LR 390; Liverpool CC v Irwin (1977) AC 239; Codelfa Construction, supra, n 28.

31. Gillespie Bros v Roy Bowles Ltd (1973); 1 QB 400 at 421; and see also Wickham Tube v Schuler (1974) AC 235 at 251; Levison v Patent Steam Cleaning Co (1978) QB 69 at 79; Alex Lobb Ltd v Total Oil GB Ltd (1985) 1 All ER 303 at 312. The reasonableness test has been taken over by the Unfair Contract Terms Act 1977, s 3(2)(b)(ii). The corresponding American notion of ‘unconscionability’ (Uniform Commercial Code, s 2–302), though it seems wider, yet does not purport to disturb the allocation of risks such as the parties agreed to between themselves, not even if there is superior bargaining power on one side: superior bargaining power must in any case be distinguished from unequal bargaining position which latter, but not the former, may give rise to voidability. For a criticism of unconscionability, see A A Leff, Unconscionability and the Code (1967) 115 Univ Of Penn LR 485, and for a wider attack C Fried, Contract As Promise (Harvard, 1981) pp 20–1, 92, 103, according to whom judicial compassion can lead to a paternalism that fails to take the promisor sufficiently seriously as a person, rather infantilising him.

32. For what now seems a clear recognition of this, see Davis Contractors v Fareham UDC, supra, n 28, at 728; and The Eugenia, ibid, at 238.