The standard philosophical view of promises, and it applies also to contracts and treaties, is most easily understood if it is approached via the theory of property. We can think of property as anything from houses to umbrellas and it is now extended to include intellectual property. It is possible to imagine a society without property – perhaps a commune or a kibbutz might approximate to one such – but even there its inhabitants might want their own toothbrushes.
Overwhelmingly, property is a useful and desirable institution. But for property to work smoothly as an institution there must be rules for ownership, buying, selling and exchanging. Many of these will form part of both the civil and the criminal law, and they will be governed by conceptions of what is fair or just.
We can think of promises along the same lines, as a practice or institution which has developed over millennia because it has utility – it makes life more convenient and co-operative. If someone says 'I hope to do X', we expect that they might but wouldn't be surprised if they didn't. If they say 'I intend to do X', our expectations are greater because they are putting the consistency of their words and deeds on the line. But if they say 'I promise to do X', they have invoked the practice or institution of promises and given us a guarantee that they will deliver as promised. The same holds true of commercial contracts or international treaties.
We have all made promises which we wish we hadn't. Nevertheless, 'a promise is a promise', may be a tautology but it has a convincing moral ring to it. Defaulting on promises or contract or treaties gives the promisee a legitimate grievance. Occasionally, there may be the sanction of the law but more often the sanction will be a breakdown of trust for future agreed commitments and the cooling of personal, commercial or international relationships.
It might be said that the promise is binding only if it freely given and not made under duress. This is certainly correct if we think of a promise along the lines of legal contract. A promise or contract could not be legally enforced if it is established that it was made as a result of a serious threat. But failure to understand what you have agreed to or to read the small print does not count as duress.
From the moral point of view, there is a further interesting issue. Adam Smith takes the case of the highwayman who by fear of death obliges a traveller to promise him a sum of money. The question is whether such a promise, extorted by force, ought to be regarded as obligatory. Legally, it certainly is not obligatory, but Smith argues that from a moral point of view a lot depends on the details of the case.
He writes: 'Whenever such promises are violated, though for the most necessary reasons, it is always with some degree of dishonour to the person who made them… Our imagination therefore attaches the idea of shame to all violations of faith in every circumstance... Fidelity is so necessary a virtue, that we apprehend it in general to be due even to those to whom nothing else is due...' (Theory of Moral Sentiments pt VII
, para IV).
So far, I have been arguing that promising or contracting is a kind of practice which, like property, has grown up over the millennia and has utility because it makes co-operation in social life easier than it would have been without the practice. Since the 18th century, the practice has been extended through the development of international law. But if it is going to work for society as a whole, people must keep their promises, contracts or treaties and individuals or countries which don't will find that in future they are less trusted.
Many philosophers would be content to leave it at that, but, following Adam Smith, I have suggested that there may be a deeper significance to promises. When we make a promise we are, as it were, pinning our self on the future as described in the pledged actions. We are making keeping the promise central to our personal integrity. The promise breaker will be diminished as a person, and a degree of dishonour or shame will be attached to the promise breaker.
If we turn to international treaties, it is plausible to suggest that they are closely analogous to promises. We assume the contracting parties have understood the agreement and entered into it for their mutual benefit, whether commercial or military. Contracts have civil or criminal courts to scrutinise and enforce valid contracts, but it is not so straightforward for international treaties. True, there are international courts which have prosecuted crimes against humanity carried out by cruel leaders and generals. But sanctions against defaulting countries are less effective – trade embargoes can cut both ways. So we are left with the sanctions which can be used on promise-breakers – damage to reputation and lack of trust for future treaties
What of the shame which individuals can feel if they break a promise? Politicians have clearly developed a vaccine against shame. More likely, tribal loyalty gives them herd immunity. Unfortunately, there is the vicarious shame the rest of us can feel on behalf of our leaders. If the time ever comes when we can go abroad again, it will be advisable to be Scottish rather than British.
A final point applies alike to promises, contracts and treaties. They should not be entered into unless it is clearly possible that they can be carried out. Politicians are much given to making 'promises' they are not in a position to carry out.
Politician: 'We promise you a new bridge for your river.'
Civic leader: 'But we don't have a river!'
Politician: 'You haven't got a river? We promise you a river. And it will be world-beating.'
In fact, politicians don't use the word 'promise' very much; they prefer the stronger or more solemn form of promise – they offer us a 'vow'. Perhaps they believe that 'vow' sounds more convincing than 'promise'. More likely, it is because 'vow' is shorter and punchier than 'promise' and therefore more likely to get a tabloid headline. Not much shame there.